Report of the ICES Advisory Committee 2013

Transcription

1 ICES ADVICE 2013 AVIS DU CIEM Books 1 10 Report of the ICES Advisory Committee 2013 Book 9 Widely Distributed and Migratory Stocks International Council for the Exploration of the Sea Conseil International pour l Exploration de la Mer

2 H.C. Andersens Boulevard 4446 DK1553 Copenhagen V Denmark Telephone (+45) Telefax (+45) info@ices.dk Report of the ICES Advisory Committee on Fishery Management Books 1 10 December 2013 Recommended format for purposes of citation: ICES Report of the ICES Advisory Committee ICES Advice, Book pp. For permission to reproduce material from this publication, please apply to the General Secretary. ISBN

3 BOOK 9 Section Page 9 WIDELY DISTRIBUTED AND MIGRATORY STOCKS Ecosystem overview The status of fish stocks and fisheries Assessments and advice Assessments and advice regarding protection of biota and habitats Assessments and advice regarding fisheries Special requests NEAFC request to ICES to evaluate the Harvest Control Rule element of the longterm management plan for blue whiting NEAFC request to ICES to evaluate possible modifications of the longterm management arrangement for the Norwegian SpringSpawning herring stock EU request on Technical Evaluation of Eel Management Plan Progress EC request to ICES to evaluate possible modifications of the longterm management arrangement for the Western horse mackerel stock NEAFC request on effects on assessments of historical unaccounted landings for mackerel and the utility of new and existing surveys EC request to ICES to evaluate the proposed longterm management plan for boarfish and possible inyear revision of the TAC for NEAFC request to ICES to evaluate the extra harvest control rule options for the longterm management plan for blue whiting Fish stock advice Alfonsinos/Golden eye perch (Beryx spp.) in the Northeast Atlantic Angel shark (Squatina squatina) in the North East Atlantic Basking shark (Cetorhinus maximus) in the Northeast Atlantic Black scabbard fish (Aphanopus carbo) in the Northeast Atlantic Blue whiting in Subareas IIX, XII and XIV (Combined stock) Boarfish in the Northeast Atlantic European Eel Greater forkbeard (Phycis blennoides) in the Northeast Atlantic Greater Silver Smelt (Argentina silus) in the Northeast Atlantic Hake in Division IIIa, Subareas IV, VI and VII and Divisions VIIIa,b,d (Northern stock) Herring in Subareas I, II, V and Divisions IVa and XIVa (Norwegian springspawning herring) Horse mackerel (Trachurus trachurus) in Divisions IIa, IVa, Vb, VIa, VIIac, ek, and Subarea... VIII (Western stock) Kitefin shark (Dalatias licha) in the Northeast Atlantic Leafscale gulper shark (Centrophorus squamosus) in the Northeast Atlantic Ling (Molva molva) in the Northeast Atlantic Blue ling (Molva dypterygia) in the Northeast Atlantic Mackerel in the Northeast Atlantic (combined Southern, Western and North Sea spawning components) Orange roughy (Hoplostethus atlanticus) in the Northeast Atlantic Porbeagle (Lamna nasus) in the Northeast Atlantic Portuguese dogfish (Centroscymnus coelolepis) and leafscale gulper shark (Centrophorus squamosus) in the Northeast Atlantic Rays and skates (mainly thornback ray) in the Azores and MidAtlantic Ridge (ICES Divisions X, XII, XIV) Red (=blackspot) seabream (Pagellus bogaraveo) in the Northeast Atlandic Roundnose grenadier (Coryphaenoides rupenstris) in the Northeast Atlantic Smoothhounds (Mustelus spp.) in the Northeast Atlantic Red gurnard in the Northeast Atlantic Spurdog (Squalus acanthias) in the Northeast Atlantic Striped red mullet in the Northeast Atlantic Tope,(Galeorhinus galeus) in the Northeast Atlantic Tusk (Brosme brosme) in the Northeast Atlantic

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5 9 WIDELY DISTRIBUTED AND MIGRATORY STOCKS 9.1 Ecosystem overview This Section has not been updated in The most recent ecosystem overview is available in ICES Advisory Report 2008, Section 9.1. This overview can also be found on the ICES website: State of stocks and fisheries in 2013 ICES provides advice regarding the following stocks in this ecoregion Stock Angel shark (Squatina squatina) in the Northeast Atlantic Alfonsinos/Golden eye perch (Beryx spp.) in the Northeast Atlantic Greater silver smelt (Argentina silus) in Division Va Greater silver smelt (Argentina silus) in Subareas I, II, IV, VI, VII, VIII, IX, X, XII, and XIV, and Divisions IIIa and Vb (other areas) Blue ling (Molva dypterygia) in Division Va and Subarea XIV (Iceland and Reykjanes ridge) Blue ling (Molva dypterygia) in Division Vb and Subareas VI and VII Blue ling (Molva dypterygia) in Divisions IIIa and IVa, and Subareas I, II, VIII, IX, and XII Boarfish in the Northeast Atlantic Black scabbardfish (Aphanopus carbo) in Subareas VIII and IX Black scabbardfish (Aphanopus carbo) in Subareas VI, VII, and Divisions Vb and XIIb Black scabbardfish (Aphanopus carbo) in other areas (Subareas I, II, IV, X, XIV, and Divisions IIIa and Va) Basking shark (Cetorhinus maximus) in the Northeast Atlantic Portuguese dogfish (Centroscymnus coelolepis) in the Northeast Atlantic Red gurnard in the Northeast Atlantic Spurdog (Squalus acanthias) in the Northeast Atlantic European eel Tope (Galeorhinus galeus) in the Northeast Atlantic Greater forkbeard (Phycis blennoides) in the Northeast Atlantic Leafscale gulper shark (Centrophorus squamosus) in the Northeast Atlantic Herring in the Northeast Atlantic (Norwegian springspawning herring) Hake in Division IIIa, Subareas IV, VI, and VII, and Divisions VIIIa,b,d (Northern stock) Horse mackerel (Trachurus trachurus) in Divisions IIa, IVa, Vb, VIa, VIIa c,e k, and VIIIa e (Western stock) Ling (Molva molva) in Subareas I and II Ling (Molva molva) in Division Vb Ling (Molva molva) in Division Va Ling (Molva molva) in Divisions IIIa and IVa, and in Subareas VI, VII, VIII, IX, XII, and XIV (other areas) Mackerel in the Northeast Atlantic (combined Southern, Western, and North Sea spawning components) Striped red mullet in Subarea VI, VIII and Divisions VIIac, ek and IXa (Western area) Orange roughy (Hoplostethus atlanticus) in the Northeast Atlantic Porbeagle (Lamna nasus) in the Northeast Atlantic Rays and skates (mainly thornback ray) in ICES Subareas X, XII, and XIV (Azores and MidAtlantic Ridge) Roundnose grenadier (Coryphaenoides rupestris) on the MidAtlantic Ridge (Divisions Xb and XIIc, and Subdivisions Va 1, XIIa 1, and XIVb 1) Roundnose grenadier (Coryphaenoides rupestris) in Subareas VI and VII, and Divisions Vb and XIIb Basis for stock status and advice Data limited Data limited Data limited Data limited Data limited Data limited Data limited Analytical Data limited Data limited Data limited Data limited Data limited Data limited Data limited Data limited Data limited Data limited Data limited Analytical Analytical Analytical Data limited Data limited Data limited Data limited Analytical Data limited Data limited Data limited Data limited Data limited Analytical ICES Advice 2013, Book 9 1

6 Roundnose grenadier (Coryphaenoides rupestris) in Division IIIa Roundnose grenadier (Coryphaenoides rupestris) in all other areas (Subareas I, II, IV, VIII, and IX, Division XIVa, and Subdivisions Va 2 and XIVb 2) Red (=blackspot) seabream (Pagellus bogaraveo) in Subareas VI, VII, and VIII Red (=blackspot) seabream (Pagellus bogaraveo) in Subarea IX Red (=blackspot) seabream (Pagellus bogaraveo) in Subarea X (Azores region) Kitefin shark (Dalatias licha) in the Northeast Atlantic Smoothhounds (Mustelus spp.) in the Northeast Atlantic Tusk (Brosme brosme) in Subareas I and II (Arctic) Tusk (Brosme brosme) in Division Va and Subarea XIV Tusk (Brosme brosme) in Subarea XII, excluding Division XIIb (MidAtlantic Ridge) Tusk (Brosme brosme) in Divisions IIIa, Vb, VIa, and XIIb, and Subareas IV, VII, VIII, and IX (other areas) Tusk (Brosme brosme) in Division VIb (Rockall) Blue whiting in Subareas I IX, XII, and XIV Striped red mullet in Subareas and Divisions VI, VIIa c, e k, VIII, and IXa (Western area) Data limited Data limited Data limited Data limited Data limited Data limited Data limited Data limited Analytical Data limited Data limited Data limited Analytical Data limited The state and advice of the individual stocks are presented in the stock sections. An overview of the status of the stocks for which information on fishing mortality and spawning stock biomass is available, as assessed for 2012 in 2013, is presented in table Table Status of data rich stocks (n=7) for the widely distributed stocks relative to MSY and PA reference points for Fishing Mortality (F) and Spawning Stock Biomass (SSB). Table shows percentage of stocks per stock status. Values in brackets denote the number of data rich stocks per stock status. Northeast Atlantic mackerel is not included in this table. MSY Approach Fishing Mortality is at or above MSY B trigger SSB 2013 > MSY B trigger Spawning Stock Biomass is below MSY B trigger SSB 2013 < MSY is not defined B trigger is at or below MSY (F 2012 < F MSY) 43%(3) 29%(2) is above MSY (F 2012 > F MSY) 14%(1) is not defined 14%(1) is at or above PA SSB 2013 > B pa is at increased risk B pa > SSB 2013 > B lim is below limit SSB 2013 < B lim is not defined Precautionary Approach Fishing Mortality is at or below P (F 2012 < F pa) is at increased risk (F lim > F > F pa) is above PA (F 2012 > F pa) 29%(2) is not defined 71% (5) 2 ICES Advice 2013, Book 9

7 Although there is considerable variation between stocks and large yeartoyear variation for most stocks, the overall fishing mortality has been decreasing over the last couple of decades. The biomasses have overall increased in the same period and have in the last few years been increasing (figure 9.2.1). Figure Trend in fishing mortality and spawning stock biomass relative to the average for each stock over the time for which data are available. The graphs include data for the stocks for which such estimates are available. The thick (red) line represents the average for all the stocks. ICES Advice 2013, Book 9 3

8 Of the stocks for which information exists, 4 out of 5 is at or below Fmsy while 1 is above Fmsy. All the stocks for which information exist are above MSY Btrigger (figure 9.2.2). Figue The status of fish stocks relative to reference points (Fmsy, MSY Btrigger) for those stocks for which this is available. The dotted (red) line represents the ratio 1. 4 ICES Advice 2013, Book 9

9 9.3 Ecosystem Assessments and Advice Assessment and advice regarding protection of biota and habitats In 2012, ICES has not provided advice regarding protection of biota and habitats for this area Assessments and Advice regarding fisheries ICES Advice 2013, Book 9 5

10 9.3.3 Special requests Special request, Advice May 2013 ECOREGION Widely distributed and migratory stocks SUBJECT NEAFC request to ICES to evaluate the harvest control rule element of the longterm management plan for blue whiting Advice summary ICES has evaluated the reference points and concluded that B lim and B pa should remain unchanged. New values of F pa = 0.32 and F lim = 0.48 have been provided that are consistent with these biomass reference points. The corresponding MSY reference points are F MSY = 0.30 and MSY B trigger = 2.25 million t. The current management plan is considered precautionary. A number of alternative F targets in the range of were evaluated for the current harvest control rule (HCR) form and found to be precautionary up to an F target of 0.32 (corresponding to F pa), with only a minimal increase in mean TAC for F targets above 0.3. Inclusion of catch stabilization mechanisms have been tested in the current HCR and are considered precautionary as they do not increase the probability of SSB< B lim above Over the entire time period examined there are no significant differences in catch either with or without the stabilizers. The rule may lead to considerably reduced interannual variation (IAV), but can generate high Fs during periods of stock decline and lower catches during periods of stock increase. Initial evaluations indicate that a number of options for the newly proposed HCR form (with increasing F at high biomass) have been found to be precautionary. However, these preliminary evaluations are not considered sufficiently robust. Based on the results presented, ICES suggests that a small subset of such rules should be selected and tested further with greater rigour before they are judged suitable for precautionary management. Testing of banking and borrowing scenarios showed very little impact of either extreme banking or borrowing. Allowing a maximum of 10% to be banked or borrowed any year is considered precautionary when used with the existing HCR. Request 1. In accordance with point 7 of the Agreed Record of Fisheries Consultations between Iceland, the European Union, the Faroe Islands and Norway on the management of blue whiting in the NorthEast Atlantic, signed on 11 October 2011, it was agreed to conduct a review of the longterm management plan. 2. In order to facilitate discussions between Coastal States on possible modifications to the longterm management plan for blue whiting, ICES is requested by NEAFC, by 1 June 2013, to reevaluate the reference points B lim, B pa and F msy for the stock and to conduct an evaluation of the harvest control rule under the existing management plan. 3. ICES is further requested to evaluate the harvest control rule with the following stability mechanisms when the SSB is above B lim: a. Setting a TAC in the TAC year based on the average of the projected TACs at target F over three years starting with the TAC year. b. Setting the TAC to be the average of the current TAC and the TAC that would result from the application of the harvest control rule for the TAC year. 4. ICES is also requested to evaluate the following approach shown in Fig 1. 6 ICES Advice 2013, Book 9

11 The harvest rule fixes a TAC, harvest rate or fishing mortality, the level of which depend on the estimated biomass, as follows: A lower bound below Trigger B1; A linear sliding scale with slope a1 below Trigger B1; A standard level applied between Trigger B1 and Trigger B2; A linear sliding scale with slope a2 above Trigger B2; and An upper bound at higher stock sizes. ICES is asked to evaluate appropriate values for each of the parameters identified above in relation to stability, and maximum sustainable yield on a longterm basis. 5. With regard to the above requests, ICES is further requested to undertake an evaluation with respect to application of interannual quota flexibility of +/ 10% for the blue whiting stock. In the text below, current HCR form refers to harvest control rules that exclude Trigger B2, Slope a2, and the upper bound (i.e. includes everything to the left of Trigger B2 in Figure 1 of the request). Proposed HCR form refers to HCRs that include all the elements contained in Figure 1. Elaboration on the advice Reevaluation of reference points ICES has evaluated the reference points and concluded that B lim and B pa should remain unchanged. F pa and F lim were undefined. Equilibrium stochastic simulations have been used to give a new value for F lim = On the basis of this and the uncertainty in the assessment, a corresponding value for F pa = 0.32 was derived. Currently MSY advice is based on a management strategy evaluation which used F 0.1 as a proxy for F MSY and an MSY B trigger = B pa. The new simulations provide estimates of F MSY = There are no scientific reasons to reduce MSY B trigger below B pa, and no estimates of MSY B trigger are above B pa. Under these circumstances it is proposed that B pa be retained as MSY B trigger for the MSY framework. Evaluation of options for HCRs The current management plan has been evaluated and is considered precautionary. Evaluations indicate that the probabilities of SSB< B lim are low. A number of alternative F targets in the range of for the current HCR form (Figure 1 of the request, leaving out Trigger B2 and everything above that) have been evaluated and found to be precautionary up to an F target of The inclusion of catch stabilization clauses in the current HCR form have been tested and are considered precautionary. The whole time period was examined and showed no significant differences in catch with or without the stabilizers. ICES Advice 2013, Book 9 7

12 Neither of the stability mechanisms significantly increase the probability of SSB< B lim. Both rules (See below) can greatly reduce the IAV but result in delayed management reactions in response to changes in the level of recruitment. This can generate rather high Fs during periods of stock decline and result in lower catches during periods of stock increase. The transition from high to low recruitment in the 3year rule (see below) may have higher probabilities of SSB< B lim in reality than is concluded from the current simulations. The tests carried out assume that the normal and high recruitment regimes are known and that shortterm forecasts are adjusted correctly. This knowledge would not be available in the real world, i.e. the current tests imply better knowledge of the recruitment process than is currently available. A number of new HCRs that follow the proposed form (Figure 1 of the request), with increasing F/HR/TAC (targets based on Fishing mortality/harvest Rate (TAC/SSB)/or TAC directly) at high biomass, have been evaluated and some have been found to be precautionary. However, the evaluation that was possible to be conducted during the time available is not considered sufficiently robust. A number of important additional areas have been identified to give more realistic exploration: The simulated assessment uncertainty may not reflect the measurement uncertainty that has actually been experienced in recent years (e.g. the revision of the assessment in 2011 (exclusion of the 2010 survey point) which lead to a significant change in the perception of the stock). Underestimating this error may give overly optimistic performance results. The more complex HCRs need to be more comprehensively tested for robustness to greater uncertainty. It is unclear if the major reduction in fishing opportunities that occurs when recruitment regimes change from high to normal state would be implemented with the same compliance as normal changes in TAC under the new HCRs. Current tests assume compliance will be good with only minor random errors. The tests carried out assume that the normal and high recruitment regimes are known and the shortterm forecasts are adjusted correctly. This knowledge would not be available in the real world i.e. the current tests imply better knowledge of the recruitment process than is currently available. This is particularly important when testing HCRs with several biomass related triggers. Simulations have been based on stock and recruitment models without uncertainty in the mean level of recruitment. So the robustness of the biomass trigger points has not been fully evaluated. Suggestions ICES considers that testing the full range of HCRs and the complexities currently under consideration would require a large amount of time and resources which are currently not available. This particularly relates to testing HCRs that include higher Fs at high biomass. ICES suggests that managers should use the results presented here and in the expert working group report (ICES, 2012a) to identify a small subset of such rules to be tested with greater rigour against precautionary and MSY criteria. Two extreme cases of banking and borrowing were evaluated (either continually banking or borrowing the full allowable amount). These were found to have a limited impact on the performance of the current HCR. However, it is very uncertain how this process would be implemented in reality. Basis of the advice Background A management plan was agreed by Norway, the EU, the Faroe Islands, and Iceland in 2008 (ICES, 2012b). The plan uses: i) a target fishing mortality (F = 0.18) if SSB is above SSB MP (= B pa), ii) a linear reduction to F = 0.05 if SSB is between B pa and B lim, and iii) F = 0.05 if SSB is below B lim. In order to facilitate discussions between Coastal States on possible modifications to the longterm management plan for blue whiting in the Northeast Atlantic, ICES was requested by NEAFC to conduct an evaluation of the harvest control rule elements under the existing longterm management plan as outlined in the full request description above. Results and conclusions Reference points 8 ICES Advice 2013, Book 9

13 Longterm equilibrium stochastic simulations (Figure ) were carried out to determine reference points for the stock. The yield and SSBperrecruit with recent averages for weights, maturities, natural mortalities, and selectionatage (threeyear averages, as per the ICES shortterm forecast) and using the normal recruitment scenario are shown in Figure F 0.1 from this analysis is 0.22 which compares with 0.18 from an evaluation at the time of the previous management plan evaluation, which was eventually adopted as the HCR F target. F lim and F pa are evaluated from the same analysis. At F = 0.48 there is a 50% probability of SSB< B lim. Hence F = 0.48 is proposed as a value for F lim. Following standard ICES procedures and taking the precision of the SAM assessment for this stock into account leads to an associated F pa value of F = 0.32 also corresponds to a roughly 5% probability of SSB< B lim. The precautionary biomass reference points remain unchanged. F MSY is obtained from the longterm stochastic yield curve which peaks at F = 0.35 (Figure ), though there is only a small difference in equilibrium yield between Fs of 0.30 and Fishing at the peak F = 0.35 leads to a greater than 5% probability of SSB< B lim, hence F MSY must be reduced so that it is precautionary and the recommended value is therefore F MSY = Current management plan The current HCR was reevaluated in three different recruitment scenarios: NHN (normal recruitment, followed by a 9year period of high recruitment, followed by normal recruitment again), normal (excluding a period of high recruitment), and low (excluding high recruitment and peaks in recruitment). The low scenario can be considered a worst case scenario, while the NHN scenario is used primarily to see how HCRs behave under conditions of changing productivity and stock size. Figure shows the mean recruitment for each scenario and the annual probability of SSB< B lim. Under all scenarios of recruitment the probability of SSB< B lim is very low (< 1%). Figures and show more details of the performance of the current HCR with normal recruitment. Following the new proposal of reference points for the stock, runs considering alternative F target values (with the same B trigger) were conducted. Figure shows the mean performance over time of a subset of these runs with normal recruitment. Figure shows the relationship between F target and mean TAC and TAC IAV as well as SSB and the probability of SSB being below B lim and B trigger over the last ten years simulated. Mean performance over the last ten years is also presented in Table For F targets above 0.25 there is little additional gain in TAC in the long term, but IAV in TAC increases with increasing F target. This is partly due to SSB stabilizing in the region of B trigger for F targets >0.25, which results in the F used to calculate TAC often being less than the F target value. Hence changes in TAC arise due to both changes in F from the HCR and changes in stock biomass. F targets above 0.32 are not considered to be precautionary. Stability mechanisms Three potential stability mechanisms applied to the current HCR were evaluated in the NHN recruitment scenario. 1. The 3year rule where the TAC is set as the average of the projected TAC for three years (part 3a in the request). 2. The rule where the TAC is set as the average of the previous TAC and the HCR TAC for the next year (part 3b in the request). 3. The HCR50 50 rule where the TAC is set as the average of the previous HCR TAC and the current HCR TAC for the next year (part 3b in the request). The NHN recruitment scenario was used specifically to see how these stability mechanisms work under scenarios of changing recruitment regime. Figure shows the mean performance of the current HCR compared to the performance of the current HCR with stability mechanisms applied. Table shows the mean performance statistics over three distinct recruitment and stock status periods and over the whole time period. Resulting values are merely indicative of relative performance and should not be interpreted as absolute values. The 3year rule reacts quickest to changes in the level of recruitment, leading to higher TACs during the period of high recruitment and an increasing stock. The TAC IAV also has a peak over this period, and on average over the whole time period this stability mechanism actually increases the IAV. The rule has the lowest IAV, but is also the slowest to react to changes in the level of recruitment. This leads to lower TACs when stock size is increasing and higher TACs when stock size is decreasing. This in turn leads to large fluctuations in the level of F exerted on the stock. By altering this rule to use the average of the TAC given by the HCR in the previous year (rather than the agreed TAC), ICES Advice 2013, Book 9 9

14 HCR50 50 rule this effect is dampened. All the stability rules tested are precautionary with a target F = 0.18, but it is unsure if this would still hold for F target values higher than 0.18 (at an F target of 0.18 the rule still has a maximum annual probability of SSB< B lim of 0.033). Proposed HCR The proposed HCR contains a large number of parameters and options for decision basis (total [TSB] vs spawning stock biomass [SSB]) and advice mechanisms (HR vs TAC vs F). TSB vs SSB A test was run to examine the performance when TSB is used rather than SSB. The general impression is that the performance is largely the same in terms of probability of SSB< B lim and average catch. Using TSB allows for slightly quicker reactions to changes in stock size at the cost of incorporating more poorly estimated age classes (1 and 2). All options presented below use SSB as the decision basis. Harvest rate rule option The mean catch always increases with decreasing Trigger B2, i.e. the lower the biomass when the rate exploitation increases again, the higher the average catch. Trigger B2 should be above what can be expected under the normal recruitment scenario, which has a 95% probability when it is in the region of 4000 kt. Accordingly, Trigger B2 was fixed at 4000 kt when exploring HR options. Although the probability of SSB< B lim is still mostly tolerable within the range examined, a more drastic response to an assumed regime shift is probably not advisable, since the actual conditions in such a case may deviate from what is assumed here. Selections of low, medium, and high standard targets for the HR, TACs, and Fs rules were made and then examined further by scanning over a range of Slope a2 and Upper bound HR options (assuming a Trigger B2 of 4000 kt). The mean performance statistics for these exploratory runs are shown in Tables To explore the proposed HCR further, runs were done for the current HCR with added Trigger B2 and Slope a2 parameters. Examples are plotted in Figure for an option with low Trigger B2 and high Slope a2 (early and large changes to exploitation rate at high biomass) and an option with high Trigger B2 and low Slope a2 (later and more gradual changes to exploitation rate at high biomass). Results of more options for Trigger B2 and Slope a2 are presented in Table For all options examined, average TAC, IAV, mean F, and probability of SSB<B lim were all higher than for the current HCR with target F = The current HCR allows SSB to become higher during and following periods of high recruitment. Similar benefits in average TAC could be obtained by increasing the target standard F without including the option to increase exploitation rate at high biomass; the additional yield at high biomass by fishing harder is very small, but the yield is taken sooner and with greater IAV. Selecting appropriate values for Trigger B2 and Slope a2 will require trading off the level of standard F and the rate of increasing exploitation. The higher the standard F, the less frequent F should change to the top exploitation regime (i.e. Trigger B2 should be set higher) and there should be more gradual increases in exploitation to be prudent (lower Slope a2). With a lower standard F, more frequent changes to the top exploitation rate (i.e. lower Trigger B2) and rapid increases in exploitation rate at high biomass (higher Slope a2) may still be precautionary. Banking and borrowing Two extreme banking and borrowing scenarios were examined, one in which the maximum allowable amount is banked every year (BBminus), and another where the maximum allowable amount is borrowed every year (BBplus). These scenarios were applied to the current HCR and compared to a scenario with no banking or borrowing. The results show very minor differences in longterm performance, with all cases being precautionary. Methods For the evaluation of the HCRs a stochastic simulation model was used. Parameterization of the model was based on the latest information of the stock from WGWIDE 2012 (ICES, 2012a). The model was run from 2012 to 2042 or 2052, depending on the recruitment scenario applied, for 1000 stochastic iterations (replicate runs). Stochasticity was implemented in weightatage in the stock, catch, initial stock numbers, recruitment, and implementation and observation parts of the model. Natural mortality, maturation, and fisheries selectivity were deterministic. 10 ICES Advice 2013, Book 9

15 Recruitment was simulated to reproduce patterns and levels observed in the past. Blue whiting has historically had recruitments at a baseline level with occasional strong year classes at about 6 to 7year intervals. In the period , recruitments were far better, and this is regarded as a different regime. Accordingly, three different recruitment regimes were used, with parameters derived from the historical data: 1. Normal recruitment: corresponding to all year classes except , including occasional spikes (every 6 7 years). 2. Normal high normal (NHN) recruitment: a period of normal recruitment, then high recruitment for 9 years, then normal recruitment again. 3. Low recruitment: as for normal recruitment, without the occasional spikes. The 'true' stock numbers were modified by an observation model to provide stock numbers for the decision process. This observation model mimics the uncertainty expected from the SAM assessment for this stock. In the decision process, recruitment predictions in the shortterm forecast were according to the deterministic stock recruitment function, with parameters representing the regime at the beginning of the projection period, which here is the year before the TAC year (i.e. the current recruitment regime was known when setting TACs based on the HCR). It was noted that some elements of the rules that were tested relied heavily on the assumptions in the modelling that biomass reference points were accurately defined relative to modelled recruitment and that the current recruitment regime was known when carrying out shortterm forecasts. Simulations are required that include more realistic uncertainty in mean recruitment and where the transition between recruitment regimes is not known but must be detected. Sources ICES. 2012a. Report of the Working Group on Widely Distributed Stocks (WGWIDE), August 2012, Lowestoft, UK. ICES CM 2012/ACOM: pp. ICES. 2012b. Section Blue whiting in Subareas I IX, XII, and XIV (Combined stock). In ICES Advice 2012, Book 9: Figure Stochastic and deterministic equilibrium yield and SSB under the normal recruitment scenario. ICES Advice 2013, Book 9 11

16 Figure Mean annual recruitment (left) and maximum annual probability of SSB< B lim (right) for the current management plan harvest control rule in three recruitment scenarios: NHN (blue, high recruitment period included), normal (red, excluding high recruitment period), and low (yellow, excluding high period with no occasional peaks). Figure Performance of the current management plan harvest control rule in the normal recruitment scenario ( ). Means, medians, and confidence bounds of TAC, TAC IAV (interannual variation), mean F, and SSB are plotted. 12 ICES Advice 2013, Book 9

17 TAC Absolute IAV Year Year Mean F (37) SSB Year Year Figure Five random trajectories (individual runs) of the current management plan harvest control rule in the normal recruitment scenario ( ): TAC, TAC IAV (interannual variation), mean F, and SSB. ICES Advice 2013, Book 9 13

18 TAC F target Absolute IAV Year Year Mean F (37) SSB Year Year Figure Mean performance for the current management plan HCR using alternative target F values in the normal recruitment scenario. Figure Left: Mean TAC and mean interannual variation in TAC. Right: SSB (blue) and the maximum annual probability of SSB being below B lim (1500 kt) and B trigger (2250 kt) for the current management plan HCR, using alternative target F values. Values are for the last ten years ( ) in the normal recruitment scenario. The dashed line () indicates 5% probability of SSB being below B lim or B trigger. 14 ICES Advice 2013, Book 9

19 Figure Mean performance of the current management plan HCR with and without alternative TAC stability mechanisms in the NHN recruitment scenario. The vertical dashed lines in the SSB plot indicate the period with high recruitment. ICES Advice 2013, Book 9 15

20 Figure Performance of example runs adding alternative Trigger B2 and Slope a2 values to the current HCR in the NHN recruitment scenario. Table Mean performance in the last ten years ( ) for the current management plan HCR using alternative target F values in the normal recruitment scenario. The TAC and SSB values are in thousand tonnes. F targe t TA C Mean F SSB Low F Current target New F Propose d FMSY 1 Propose d FPA 8 High F TAC IAV % Max. annual prob. SSB< Blim Max. annual prob. SSB< Btrigger ICES Advice 2013, Book 9

21 Table Mean performance of the current management plan HCR with and without alternative TAC stability mechanisms in the NHN recruitment scenario. Results are presented for (normal recruitment, stable stock), (high recruitment, increasing stock), (normal recruitment, decreasing stock), and for the whole time period. The TAC and SSB values are in thousand tonnes Normal stable stock HCR TAC F SSB TAC IAV Max. annual prob. Max. annual prob. % SSB< Blim SSB< Btrigger Current year rule (3a) (3b) HCR50 50 (3b) High Recruitment Regime increasing stock HCR TAC F SSB TAC IAV Max. annual prob. Max. annual prob. % SSB< Blim SSB< Btrigger Current year rule (3a) (3b) HCR50 50 (3b) Normal decreasing stock HCR TAC F SSB TAC IAV Max. annual prob. Max. annual prob. % SSB< Blim SSB< Btrigger Current year rule (3a) (3b) HCR50 50 (3b) ALL Whole time period HCR TAC F SSB TAC IAV Max. annual prob. Max. annual prob. % SSB< Blim SSB< Btrigger Current year rule (3a) (3b) HCR50 50 (3b) Table HR rule (TAC/SSB) in the NHN recruitment scenario. Means over years , which includes a period of high recruitment followed by 10 years of normal recruitment. Trigger B2 = 4000 kt in all cases. The mean catches are in thousand tonnes. Low Std HR Medium Std HR High Std HR Std HR Slope a2 Upper bound HR Mean catch: percentiles Prob. SSB< Blim ICES Advice 2013, Book 9 17

22 Table TAC rules in the normal recruitment scenario examples of candidate rule parameters. Trigger B1 and B2, TAC, mean catch, and mean SSB values are in thousand tonnes. Low Std TAC Medium Std TAC High Std TAC Trigger B1 Std TAC Slope a1 Trigger B2 Slope a2 Upper bound TAC Mean catch: percentiles Mean SSB: percentiles Prob. SSB< Blim All options show a high probability of SSB< Blim. Table F rules in the normal recruitment scenario examples of candidate rule parameters. Trigger B2, mean catch, and mean SSB values are in thousand tonnes. Low Std F Medium Std F High Std F Trigger B2 Std F Slope a2 Upper bound F Mean catch: percentiles Mean SSB: percentiles Prob. SSB< Blim Table Mean performance (all years) of example runs adding alternative Trigger B2 and Slope a2 values to the current HCR in the NHN recruitment scenario. Trigger B2, SSB, and TAC values are in thousand tonnes. Current HCR Low Trigger B2 High Trigger B2 Trigger B2 Slope a2 Mean F SSB TAC Abs. IAV in TAC Prob. SSB< Blim Prob. SSB < Trigger B Table Mean performance (all years) of the current HCR with and without banking and borrowing scenarios in the NHN recruitment scenario. The catch and SSB values are in thousand tonnes All years HCR Catch F SSB TAC IAV % Current BBminus BBplus Max. annual prob. SSB< Blim Max. annual prob. SSB< Btrigger ICES Advice 2013, Book 9

23 Special request, Advice May 2013 ECOREGION Widely distributed and migratory stocks SUBJECT NEAFC request to ICES to evaluate possible modifications of the longterm management arrangement for the Norwegian springspawning herring stock Advice summary ICES advises that B lim, B pa, and F MSY remain unchanged (A in the request). Given the current status of the stock the current management plan (A in the request) has a probability >0.06 of SSB< B lim in In the short term, ICES advises against increasing target F (0.125) in the management plan (B and C in the request) as stock size is currently relatively low and decreasing. Given the current status of the stock, all of the evaluated HCRsin the request have a probability >0.05 of SSB< B lim in The stock assessment has shown bias over the last 15 years such that the stock has been overestimated on average by 26%. This overestimation means that the stock has been fished at higher Fs than intended under the plan. With the current management plan, the shortterm probability of SSB< B lim increases from 0.061, if no bias is assumed, to 0.77 if the historical bias is incorporated. Under the assumptions for normal recruitment used in the HCRs, the simulations show that the population is expected to increase. Currently ICES is unable to determine the source of the recent bias or predict whether it will continue or not. Request In accordance with the Agreed Record of Fisheries Consultations of 14 October 2011 on the Management of the Norwegian Spring Spawning (Atlanto Scandian) Herring Stock in the Northeast Atlantic for 2012, the Coastal States shall submit a request to ICES, which will evaluate the consistency of possible modifications of the longterm management arrangement, including notably the maximum sustainable yield for the stock. The results of this analysis shall be presented at the next consultations of the Coastal States on the management of the herring stock for The existing management plan consists of the following elements; 1. Every effort shall be made to maintain a level of Spawning Stock Biomass (SSB) greater than the critical level (B lim) of t. 2. For the year 2001 and subsequent years, the Parties agreed to restrict their fishing on the basis of a TAC consistent with a fishing mortality rate of less than for appropriate age groups as defined by ICES, unless future scientific advice requires modification of this fishing mortality rate. 3. Should the SSB fall below a reference point of t (B pa), the fishing mortality rate referred to under paragraph 2, shall be adapted in the light of scientific estimates of the conditions to ensure a safe and rapid recovery of the SSB to a level in excess of t. The basis for such an adaptation should be at least a linear reduction the fishing mortality from at B pa ( t) to 0.05 at B lim ( t). 4. The Parties shall as appropriate review and revise these management measures and strategies on the basis of any new advice provided by ICES. ICES has already assessed the fishing mortality that generates Maximum Sustainable Yield (F msy) to F=0.15. ICES has also established the reference point B trigger to t, and we understand that these two reference points are connected as follows; When the SSB of Norwegian spring spawning herring is assessed to be above t, fishing should be on the basis of a fishing mortality at F msy (0.15), whereas this fishing mortality should be reduced if the SSB is assessed to be below this trigger point. To assess whether the existing long term management plan for Norwegian Spring Spawning Herring should be amended the Parties would request ICES to assess: A. The existing long term management plan, including the reference points. ICES Advice 2013, Book 9 19

24 B. The existing long term management plan modified by substituting the fishing mortality of referred to in paragraph 2 and 3 of the existing plan with a fishing mortality corresponding to F msy (0.15), and B pa with B trigger. C. The existing long term management plan modified by substituting the fishing mortality of referred to in paragraphs 2 and 3 of the existing plan with a fishing mortality corresponding to F msy (0.15) when the average recruitment for a recent period with an appropriate time lag is equal to or above the long term mean. If the average recruitment in that period is below the long term mean, the currently applied fishing mortality of shall be used. ICES is requested to evaluate different options of recent periods, time lags, and long term mean. When simulating the consequences of the existing and the amended management plans (B and C), fishing mortality should be kept equal to 0.05 when SSB is below B lim. Concerning the amended management plans, ICES is also requested to simulate the consequences of this with a specification stating that fishing mortality is reduced linearly from F msy at B trigger to zero when SSB is assessed to be zero. Each alternative should be assessed in relation to how they perform to produce maximum long term yield as well as in relation to the precautionary approach. To assess their performance in relation to these two aspects, the Parties would ask ICES to produce figures according to the following indicators; Medium term yield, represented as average yield during the next 10 years Long term yield, represented as average yield during the next 50 years Probability that SSB falls below B trigger, in a 5 and 10 year period and in a 50 year period Probability that SSB falls below B lim, in a 5 and 10 year period and in a 50 year period ICES is also requested to assess what, if any, other measures in addition to those contained in the present Management Plan might contribute to attaining the objectives of the plan, and provide estimates of their efficiency. Finally, ICES is requested to give advice on TAC for 2013 according to the existing management plan, but should also identify a TAC for 2013 according to an amended long term management plan recognized by ICES to be in accordance with the precautionary approach. Elaboration on the advice Reference points ICES has reevaluated the B lim and concluded that it should remain unchanged at 2.5 million tonnes. B pa is not to be revised as it is defined based on B lim. ICES has evaluated F MSY and considers it should remain unchanged at F MSY = Evaluation of harvest control rules ICES advises that an increase in target F (0.125) in the management plan (i.e. HCRs 2 and 5) should not be considered in the short term. The stock size is currently relatively low and decreasing. Given the current status of the stock, all of the evaluated HCRs have a probability >0.05 of SSB< B lim in SSB is expected to decline until 2017, mostly due to the lack of strong year classes in the period 2005 to Modifying the current plan by allowing for a higher F (F = 0.15) when recent recruitment (the mean over a fiveyear period) has been observed to be above the longterm mean recruitment (125 billions; see HCRs 3 and 6) results in marginal increases in the average catches (a maximum 3.5% increase in yield in the intermediate term compared with the current management plan). The probability of SSB falling below B lim would increase only slightly. Modifying the current plan with a higher target F (F = 0.15) results in relatively small increases in catch (see HCRs 2 and 5), and these are associated with higher probability of SSB< B lim. Given the anticipated decline, an increase in F should only be considered when SSB is estimated to be above B pa. Suggestions Applying the present HCR does not reduce the F enough if SSB drops below B trigger of 5 million tonnes and gives a probability of >0.05 that SSB< B lim. In the short term a probability of 0.05 that SSB< B lim is achievable by increasing B trigger to 6 million tonnes. This is equivalent to a reduction of the average F in the short term to (HCRs 1, 3, 4, 20 ICES Advice 2013, Book 9

25 and 6; see Table ). A similar reduction in the probability of SSB< B lim could also be achieved by using a constant F (Figure ) until Before increases in F are advised the bias in the assessment should be taken into account, as overestimation might lead to increased probability of SSB< B lim. In the last 15 years the tendency has been to overestimate the stock by 26% on average. The catches have thus been taken at a higher F than advised, which may have contributed to the decline in SSB. Given the current situation of declining stock size, TAC stabilizers (constraint on the interannual change in TAC) should not be used. During a downward trend in the stock size a stabilizer will keep the TACs higher than advisable. There are no obvious advantages to applying TAC stabilizers in the intermediate term, either. Basis of the advice Background The current harvest control rule for Norwegian springspawning herring (NSSH) has been used in providing advice since The previous target F (F = F pa = 0.15) used from 1998 to 2000 was considered to be too high and lead to too high a risk of SSB falling below B lim. Additionally, the plan had a linear reduction of F, from at B pa to 0.05 at B lim, to avoid closing the fishery completely. Taking into account ICES development of an MSY framework which suggested F MSY = 0.15, the Coastal States management organization of the Norwegian springspawning herring stock in the Northeast Atlantic submitted a request to ICES to reevaluate the longterm management plan. In addition, as NSSH is characterized by occasional strong year classes, a harvest control rule that could better react to abundant year classes entering the fishery has been suggested and an evaluation has been requested. Results and conclusions In the NSSH stock assessment, F is calculated based on numberweighted Fs. Because of software limitations the evaluation presented is based on unweighted mean Fs throughout (see discussion in the Methods section below). Reevaluation of precautionary and MSY reference points The estimates of B lim are highly dependent on the data used (assessment year and time period), and the point estimates have a wide range ( million tonnes). Though most of the estimates are greater the current B lim of 2.5 million tonnes lies within the confidence interval of all the estimates (lowest 2.5% confidence interval 0.3 million tonnes, highest 97.5% confidence interval 10.8 million tonnes), which may suggest that the B lim could be higher. The stock recruitment data over the timeseries is a combination of spawningstock biomass and recruitment values from individual stock assessments over the different periods of the series. The resulting estimates of B lim are sensitive not only to the length of the timeseries used, but also to the particular historical assessments, making it difficult to select a single preferred value. ICES therefore recommends keeping the B lim at 2.5 million tonnes. Given that B lim is unchanged, ICES does not recommend a change to B pa. A longterm stochastic equilibrium evaluation, assuming normal recruitment, was used to estimate unweighted F MSY. This was found to be negligibly different from the current value of F MSY = 0.15, which is equal to F pa and gave a probability of < 0.05 of SSB< B lim. ICES does not recommend any changes in F MSY. Harvest control rule Seven indicators were selected to evaluate the performance of HCRs implied by the request. Average annual catch Average F Average SSB Average of the interannual variability in TAC (TAC IAV) calculated as a mean (over all years in the time frame and all bootstrap replicas) of the absolute interannual variation expressed as a percentage: abs{[tac(y) TAC(y 1)]/[(TAC(y 1)+TAC(y)) /2]*100}. The maximum annual probability that the true SSB falls below B lim where this is calculated over the requested time periods (WKGMSE; ICES, 2013). According to ICES standards a HCR is considered precautionary if this probability ICES Advice 2013, Book 9 21

26 The perceived probability of the SSB falling below B trigger. This measure indicates how often the F in the advice is reduced below the target value when the perceived SSB is below B trigger. High values are indicative of higher variability in F and consequent catches. As a base case in the HCRs B trigger = B pa = 5 million tonnes was used. Simulations were run over 98 years ( ). All the indicators were estimated at five different time scales: short term (the first 5 years, ) medium term (the first 10 years, ) intermediate term (years 6 to 15, ) long term (first 50 years, ) equilibrium state (last 50 years, ). In the equilibrium state all tested HCRs (Table , Figure ) are precautionary (Table ). In the short term, all the HCRs have a probability of SSB falling below B lim >0.05. However, all HCRs except HCR 2 and HCR 5 (where target F = F MSY = 0.15) have a probability of SSB falling below B lim >0.05 only in one year (2017, see Table ). In the medium term, all HCRs except HCR 5 are precautionary. The medium and longterm periods include the highest probabilities of falling below B lim at and around year 2017, and hence also have a probability of SSB falling below B lim >0.05. Under normal recruitment all of the stock trajectories increase after the decline to In the absence of strong year classes entering the stock in the next decade SSB fluctuates between B lim and B pa but does not decline further (Figure ). This was simulated by excluding the spasmodic good year classes from the recruitment and applying the current management plan (HCR 1). In addition, the probability of SSB< B lim is >0.05 only in one year (2017; Table ). All the HCRs tested perform similarly in terms of the requested performance indicators (Tables and ). Excluding HCRs that apply F MSY (HCRs 2 and 5), the highest intermediate term yields and lowest TAC IAV appear in the strategy where F is dependent on recent recruitment and F = 0 at SSB = 0 (HCR 6, Table ). This highest average yield given by HCR 6 is 3.5% higher than the lowest average yield as seen in the current management plan (HCR 1). Probabilities of SSB< B lim do not differ significantly between the HCRs (Table ). HCRs 1, 3, 4, and 6 have an average intermediate term SSB >B pa. In the equilibrium state the highest average yield (again excluding HCRs 2 and 5), which is produced by HCR 6, is only 2% higher than the lowest average yield, produced by the current management plan (HCR 1) and the rule of F = 0 at SSB = 0 with target F = (HCR 4). The shortterm probabilities of SSB< B lim are estimated to be higher than 0.05, even though the current management plan (HCR 1), which was considered to be precautionary, has been applied. There are a number of aspects that contribute to this. The stock size in January 2013 is estimated to be 5.1 million tonnes, well below the simulation equilibrium state median of 7.1 million tonnes. Because of the recent poor recruitment SSB is likely to continue decreasing until around The stock assessment has shown bias over the last 15 years, overestimating the stock by on average 26%. This overestimation means that the stock has been fished with higher F than intended under the plan. With the current management plan (HCR 1), the shortterm probability of SSB< B lim increases from with no bias to 0.77 when 26% bias is included (Figure ). Though there is a high probability of SSB< B lim the simulations show that the populations increase again after the shortterm increase in risk (not shown in the figure). Such an increase in the probability of SSB< B lim with this bias illustrates the sensitivity of the plan to bias in measurement or implementation. Currently ICES is unable to determine the source of the recent bias or predict whether it will continue or not. Methods A stochastic simulation model was used to evaluate the HCRs. Parameterization of the model was based on the latest information of the stock from WGWIDE (ICES, 2012). The model was run for the years with 1000 stochastic iterations (replicate runs), and for five different time periods. Stochasticity was implemented in weight at age in the stock and catch, initial stock numbers, recruitment, and implementation and observation parts of the model. Natural mortality, maturation and fisheries selectivity were deterministic. Recruitment is simulated with a lognormally distributed stochastic Beverton Holt recruitment function and additional intermittent strong year classes appearing with an average interval of 8 years (with a range interval of ±2 years). It is possible to switch off the intermittent strong year classes to study the consequences of potential lack of strong year classes in the coming decade. 22 ICES Advice 2013, Book 9

27 In the NSSH stock assessment, F is calculated based on numberweighted Fs. Because of software limitations the evaluation presented is based on unweighted Fs. When comparing Fs with the assessment results, the longterm weighted Fs are lower than unweighted Fs by about 18%. However, at times of stock decline weighted F is more precautionary than unweighted F, reducing the exploitation relative to exploitation under unweighted F. Without implementing weighted F it has not been possible to estimate the difference in probability of SSB< B lim due to the use of unweighted F, but it will be less than the difference between a target F = and F = Sources ICES Report of the Working Group on Widely Distributed Stocks (WGWIDE), August 2012, Lowestoft, UK. ICES CM 2012/ACOM: pp. ICES Report of the Workshop on Guidelines for Management Strategy Evaluations (WKGMSE), January 2013, ICES HQ, Copenhagen, Denmark. ICES CM 2013/ACOM: pp. ICES Advice 2013, Book 9 23

28 TAC (1000 tonnes) F HCR HCR HCR HCR HCR HCR Year SSB (1000 tonnes) Btrigger Blim Year TAC IAV (%) Year TAC SSB Year F Year Year TAC IAV (%) Year Figure Comparison of the median time trajectories ( ) of TAC, SSB, F, and TAC IAV of the different harvest control rules (upper set of 4 plots). Lower set of plots shows five random trajectories of the same performance indicators using the current management plan (HCR 1). Year 24 ICES Advice 2013, Book 9

29 Probability of SSB < Blim 0.05 probability level Probability True F Figure The effect of constant F on the probability of SSB falling below B lim within the next 5 years. The same F has been applied through the fiveyear period. In order to achieve a probability level < 0.05, F should be Figure Mediumterm probability of SSB< B lim in the absence of strong year classes, applying the current longterm management plan (HCR 1). ICES Advice 2013, Book 9 25

30 Catch F underestimation Bias overestimation underestimation Bias overestimation SSB TAC IAV underestimation Bias overestimation underestimation Bias overestimation Probability of true SSB being below Blim Probability of perceived SSB being below Btrigger underestimation overestimation underestimation overestimation Bias Bias Figure The effect of bias. Negative bias means underestimating the stock and positive bias means overestimating the stock. The plots show the shortterm average (over the first 5 years) applying the current longterm management plan (HCR 1; black lines), and the current management plan amended with F MSY = 0.15 (HCR 2; grey lines). 26 ICES Advice 2013, Book 9

31 Table Harvest control rules evaluated. Harvest Control Rule Ref. to request SSB > Btrigger Btrigger > SSB > Blim SSB < Blim 1 Current management Option A F = Linear decrease F = 0.05 plan 2 Current management plan modified with using FMSY Option B F = 0.15 (FMSY) Linear decrease (FMSY) F = F depends on recent recruitment, modified current management plan Option C If recent recruitment longterm average, F = 0.15 (FMSY) If recent recruitment < longterm average, F = SSB >Btrigger If recent recruitment longterm average, linear decrease 0.15(FMSY) If recent recruitment < longterm average, linear decrease F = 0.05 SSB< Btrigger 4 ZeroFatzeroSSB Modified A F = Linear decrease from F = at Btrigger to F = 0 at SSB = 0 5 FMSY plan with zerofatzerossb Modified B F = 0.15 Linear decrease from F = 0.15 at Btrigger to F = 0 at SSB = 0 6 ZeroFatzeroSSB, F depends on recent recruitment 7 Increasing F at high stock size Modified C If recent recruitment longterm average, F = 0.15 (FMSY) If recent recruitment < longterm average, F = If recent recruitment long term average, linear decrease from F = 0.15 (FMSY) at Btrigger to F = 0 at SSB = 0 If recent recruitment < long term average, linear decrease from F = at Btrigger to F = 0 at SSB = 0 Current management plan amended with Btrigger2 at high SSB where F starts linearly increasing again ICES Advice 2013, Book 9 27

32 Table The performance of harvest control rules 1 6 on different time scales (B lim = 2.5 million tonnes and B trigger = 5 million tonnes). Weights in thousand tonnes. first 5 yrs HCR Catch F SSB TAC IAV % Prob. SSB< Blim Prob. SSB< Btrigger first 10 yrs HCR Catch F SSB TAC IAV % Prob. SSB< Blim Prob. SSB< Btrigger yrs 6 to 15 HCR Catch F SSB TAC IAV % Prob. SSB< Blim Prob. SSB< Btrigger first 50 yrs HCR Catch F SSB TAC IAV % Prob. SSB< Blim Prob. SSB< Btrigger last 50 yrs HCR Catch F SSB TAC IAV % Prob. SSB< Blim Prob. SSB< Btrigger ICES Advice 2013, Book 9

33 Table The probability that the true SSB falls below B lim (2.5 million tonnes) in any given year ( ). Years when the probability of SSB<B lim is >0.05 are shown in red. Year HCR 1 HCR 2 HCR 3 HCR 4 HCR 5 HCR Table Annual probability of SSB falling below B lim when no strong year classes are recruiting to the stock. The current management plan (HCR 1) is implemented (see also Figure ). Year Maximum probability of SSB< Blim ICES Advice 2013, Book 9 29

34 Table in thousand tonnes. Median, 5, and 95 percentiles of catch, F, and SSB on HCRs 1 6, for all the time periods. Weights Catch F SSB 5% Median 95% 5% Median 95% 5% Median 95% short term HCR HCR HCR HCR HCR HCR medium term HCR HCR HCR HCR HCR HCR intermediate term HCR HCR HCR HCR HCR HCR long term HCR HCR HCR HCR HCR HCR equilibrium state HCR HCR HCR HCR HCR HCR ICES Advice 2013, Book 9

35 Table Precautionary HCRs in the short term when B trigger is increased to 6.0 million tonnes (B lim = 2.5 million tonnes). For HCRs 2 and 5 B trigger needs to be increased to a level higher than 8 million tonnes and has not been evaluated. Weights in thousand tonnes. Short term (first 5 years) HCR Btrigger Catch F SSB TAC IAV % Blim max prob Blim once prob Prob Btrigger ICES Advice 2013, Book 9 31

36 Special request, Advice June 2013 ECOREGION SUBJECT progress Widely distributed and migratory stocks EU request to ICES to technically evaluate the Eel Management Plan Advice summary In most Eel Management Units (EMUs), depending on EMU conditions, progress has been made in implementing eelspecific management measures for commercial and recreational fisheries, hydropower, pumping stations and obstacles, restocking, management measures on habitat, and in a few cases predator control. According to the information provided in the EMP progress reports, management measures related to fisheries have most often been fully implemented while other management measures have often been postponed or only partially implemented. Most increases in silver eel escapement since the implementation of management plans have been achieved by management measures addressing the commercial and recreational fisheries on silver eel. Where management measures have not been fully implemented or where stock indicators show that management targets have not been reached, additional protection could be achieved by i) completing the implementation of the actions already planned, ii) implementing immediately the actions that were postponed or delayed, and iii) taking additional actions directed at the main anthropogenic mortalities. Extending actions that have proven successful, rather than pursuing untried actions or those difficult to implement, will reduce the risk of continued underachievement. Request Technical evaluation of the progress reports submitted by the EU Member States to the European Commission in line with Article 9 of the Eel Regulation (1100/2007). The reports describe the progress achieved since the implementation of the Member States' eel management plans. ICES is asked to carry out an assessment of the progress achieved via the measures implemented. In view of this, the regulation may be amended and further/additional measures may be taken in order to ensure the recovery of the eel stock. Elaboration on the advice Comparing local stock indicators provided in the 81 EMP progress reports examined and/or those provided in response to the ICES Data Call for EMU targets, 17 EMUs are reported as achieving their biomass targets, 42 as not achieving biomass targets, and 22 did not report. Of the 42 EMUs not at the target, 20 are in an upward trend towards achieving the target in the future; of the 17 currently at the target, 11 are in a downward trend and will be below the target in the future. ICES did not evaluate the reliability of the methods used to derive the stock indicators and assumed they were reliable. The biomass targets correspond to total anthropogenic mortality targets, of which 24 EMUs have reached their targets, 19 have not, and 38 have not reported all the stock indicators necessary to make this evaluation. Of the 19 not at the target, 11 are in a downward trend towards achieving their target in the future; of the 24 currently at the target, 7 show an increasing trend, which means they will no longer meet their targets in the future. ICES will try to evaluate the effect of the EMPs on the overall stock when it assesses the overall stock in the autumn, but this will be complicated because the overall stock includes waters outside of the EMUs (e.g. north Africa, Mediterranean basin, part of the Baltic basin, Norway, and Iceland). Implementation of management actions A total of 756 management actions proposed in the EMPs have been implemented fully, 259 partially, and 107 were declared not implemented at all. For 18 actions no information was available and it was not possible to determine whether these actions had been implemented or not. Effectiveness of management measures However, few EMP progress reports included data that directly demonstrate the effects of the individual management measures that have been implemented so far in increasing silver eel escapement towards EMU targets. 32 ICES Advice 2013, Book 9

37 ICES used its expertise to determine whether implemented management measures can be reasonably expected to have increased silver eel escapement, and compared these management measures to other data provided in the EMP progress reports (indirect data). For example, in comparing a measure reducing fishing effort against a reported reduction in silver eel catch, it is reasonable (but not definitive) to judge that the measure has worked. Caution must be applied however, because few EMP progress reports provide a description of the implementation of the management measures sufficient to determine this association. Using the same example, if a fishery is reduced by three months without comparing with catches during the same three months in previous years, it is impossible to evaluate the effectiveness of the measure. Management measures targeting eel stages prior to the silver eel stage are not expected to show an immediate increase in silver eel escapement. It will take one generation (between three and twenty years, depending on the EMU) before management measures on glass eel will affect silver eel escapement. Management measures targeting yellow eel will take less time. Some management measures are not expected to contribute directly to increasing silver eel escapement, e.g. those intended to gather or increase knowledge. However, applying this new knowledge should improve the quality and confidence of the calculation of stock indicators, the design and implementation of management measures that directly affect silver eel escapement, and the collection, analysis, and reporting of data to demonstrate these improvements. Most management actions were directed at commercial and recreational fisheries; the remaining management measures concerned hydropower, pumping stations, and obstacles, and finally habitat, restocking, and predator control. Other actions expected to have indirect effects, such as implementing monitoring programmes and scientific studies, were almost as common as controls on fisheries. Although substantive data were lacking from most EMP progress reports, ICES expert judgement is that restrictions on commercial and recreational fisheries for silver eel is the management measure that has contributed most to increases in silver eel escapement in the short time since the implementation of management plans. With the exception of trap and transport, where the amount of eel transported can be quantified, the effectiveness of management measures related to hydropower, pumping stations, and obstacles is difficult to demonstrate or evaluate because of the sitespecific nature of potential impacts and lack of postevaluation data. Management measures to improve habitats may reduce densitydependent mortality rates, but their effectiveness is driven by local conditions. Restocking is not expected to have contributed to increased silver eel escapement yet because of the generational lag time. The efficacy of restocking for recovering the stock remains uncertain while evidence of net benefit is lacking. Control of predators was proposed in 14 actions, but only five were fully implemented. Several predators of eel are themselves protected by European legislations and therefore control can be difficult even where these predators are considered an anthropogenicinduced mortality factor. New management actions ICES did not identify any novel management measures that were not already implemented or committed to across some EMUs. Suggestions ICES was not able to fully understand the basis for the stock indicators in some EMP progress reports as they were written in languages not understood by ICES experts at the meeting. Some EMUs did not report all required stock indicators. This made it impossible to evaluate their contribution to stock protection and recovery. All the required data should be reported for each EMU individually, to allow a full assessment of their individual contribution to stock protection and recovery. In the absence of information to determine the relative importance of EMUs to the protection and recovery of the stock, all indicators should be reported from all EMUs. This postevaluation of the 2012 EMP progress reports was hampered by the extensive variety of methods used to determine indicators, some of which were not comparable, and the confusing ways in which some data were reported. The data collection, analysis, and reporting should be standardized and coordinated. This would facilitate unequivocal postevaluation of the EMUs, and will provide for more costeffective data collection and analysis. It will facilitate the production of the wholestock indicators required to assess the status of the stock and to evaluate the EU Eel Regulation. ICES (2012a) proposed a standard form of data collection for eel assessment, but a standard analysis is lacking. The standard data collection should be implemented, and the methods developed and implemented in advance of the next postevaluation. Future evaluation of EMP progress reports would be greatly facilitated if the information was gathered electronically, submitted via a webbased service in a standardized format, and transferred to a database. ICES Advice 2013, Book 9 33

38 Basis of the advice The postevaluation is based on stock indicators of biomass and mortality, as reported by the Member States for their individual EMUs. These indicators have been derived using a broad variety of data and methods. Sources ICES. 2012a. Report of the Workshop on Eel and Salmon DCF Data (WKESDCF), 3 6 July 2012, ICES Headquarters, Copenhagen, Denmark. ICES CM/ACOM: pp. ICES. 2012b. Report of the 2012 Session of the Joint EIFAAC/ICES Working Group on Eels (WGEEL), 3 9 September 2012, Copenhagen, Denmark. ICES CM 2012/ACOM: pp. ICES Report of the Workshop on Evaluation of Progress of the Eel Management Plan 2013 (WKEPEMP), May 2013, ICES Headquarters, Copenhagen. ICES CM/ACOM: pp. 34 ICES Advice 2013, Book 9

39 Table Overview of the stock indicators provided for the EMUs, with colourcoded evaluations of whether each EMU achieves targets and trends. For the mortality, a green value for M trend, indicates that the mortality is decreasing. A green value for M target indicates that the mortality is below the target as proposed by WGEEL (ICES, 2012b). This target is the lifetime anthropogenic mortality A if the current biomass (B current) is larger than the target (i.e. 40 % of the pristine biomass (B0)), but will decrease linearly if B current is lower than the target. For the biomass, a green value for B target indicates that the EMU is larger than the biomass target (i.e. 40 % of the pristine biomass (B0)). A green value of B trend indicates that the biomass is increasing. For all values, an amber cell indicates that no data were provided to evaluate the indicator. The indicators presented here are those reported for the most recent data provided, but the trends are based on comparison between indicators before and after implementation of the EMP. %SPR is the ratio of silver eel produced per recruiting individuals under present conditions, against that estimated if no anthropogenic mortality was applied, expressed as a percentage. ICES Advice 2013, Book 9 35

40 Table (continued) 36 ICES Advice 2013, Book 9

41 Table (continued) ICES Advice 2013, Book 9 37

42 Table Stock indicators for EMU, as reported in the EMP progress report or ICES Data Call. B current is colourcoded according to whether it is greater than (green) or less than (red) the biomass target set by the EU Eel Regulation. The lifetime anthropogenic mortality A (the sum of fisheryrelated mortality ( F) and other mortality related to human activity ( H)) is colourcoded according to whether it is less than (green) or greater than (red) the mortality target equivalent to the biomass target (after WGEEL (ICES, 2012b) for A, same as Table ). The amount of restocked eel is presented in glass eel equivalents, to standardize for individuals grown to a later eel stage before restocking. Missing values are highlighted as grey cells. 38 ICES Advice 2013, Book 9

43 Table (continued) ICES Advice 2013, Book 9 39

44 Table (continued) 40 ICES Advice 2013, Book 9

45 Table (continued) ICES Advice 2013, Book 9 41

46 Table (continued) 42 ICES Advice 2013, Book 9

47 Table (continued) ICES Advice 2013, Book 9 43

48 Table (continued) 44 ICES Advice 2013, Book 9

49 Table (continued) ICES Advice 2013, Book 9 45

50 Table (continued) 46 ICES Advice 2013, Book 9

51 Table (continued) ICES Advice 2013, Book 9 47

52 Table (continued) 48 ICES Advice 2013, Book 9

53 Special request, Advice July 2013 ECOREGION SUBJECT Widely distributed and migratory stocks EC request to ICES to evaluate possible modifications of the longterm management arrangement for the Western horse mackerel stock Advice summary ICES considers that the current harvest control rule (HCR) in the Western horse mackerel management plan is not consistent with the precautionary approach (PA) because the plan is not robust to the two or more years of very low recruitment, which has been the observed for this stock since However, ICES is able to advise on alternative options for amending the current HCR based on appropriate stock and recruitment modelling. The state of the stock, the stock productivity, and the effect of the fishery on the stock have a significant impact on the value of these parameters, and these aspects need to be analysed in greater detail to fully illustrate how the HCR might be made consistent with the PA. Until these issues are addressed, ICES is neither able to advise on a suitable replacement plan nor a revision of the 2013 TAC. Request The EC has requested ICES advice on the following issue: In 2007, a management plan based on the triennial egg survey was proposed by the Pelagic RAC. The management plan was evaluated by ICES in 2007 and was found to be precautionary only in the short term because some relevant scenarios were not evaluated. ICES reviewed the plan again in 2012 and could not unequivocally conclude that the original or modified HCR is consistent with the precautionary approach in the long term. ICES further advised in 2012 that the plan should be subjected to a complete review. ICES did not advice on the basis of the management plan due to the fact it has not been established that it is precautionary in the long term. Request 1. ICES is requested to fully evaluate the plan, and ascertain whether it is precautionary in the long term as well as in the short term. 2. Should the plan be found not to be precautionary in the long term, ICES is requested to identify reinforcements in the harvesting rules that would resolve the plan's shortcomings in that respect. 3. ICES is furthermore requested to identify what TAC should apply in 2013 in accordance with a revised harvesting rule under point 2 above. Elaboration on ICES advice ICES evaluated the HCR in the management plan for western horse mackerel (ICES, 2013a). The simulations on which the original HCR was based were carried out in 2007, and since then the standards for these simulations have been amended and improved. Applying the most recent ICES standard (ICES, 2013b) to these simulations highlights shortcomings in the HCR and the basis for the calculations. As a consequence of these shortcomings ICES considers that the HCR in its original form is not consistent with the PA. In the primary findings the stock and recruitment modelling was considered inadequately conditioned (by contemporary standards and in the light of more years of data since 2007), and the HCR not robust to two or more years of very low recruitment. Since 2004 the frequency of low recruitment has increased, resulting in a potentially wider range of SSB to be taken into account in the management plan. ICES further evaluated measures to address these shortcomings (ICES, 2013a). These evaluations, with appropriate model (stock and recruitment) conditioning, show that the risks could be managed through the introduction of a protection rule in the HCR. This protection rule could take the form of an egg count threshold, below which the TAC arising from the HCR would be modified by a scalar parameter between zero and one. Results show that improved risk management comes at the cost of increased yield variability and reductions in average yield. In order to parameterize the HCR appropriately (and evaluate risks in the short and long term) the simulations need to be updated to the most recent perception of the stock, the stock productivity, and the effect of the future fishery on the stock. The combination of all of these aspects (from the 2011 assessment) has changed considerably from the values on which the original simulations were based. In general terms the 2011 assessment implies that the stock is less productive (at least recently) and that the reduced productivity is being harvested earlier by the fishery. Taken together ICES Advice 2013, Book 9 49

54 this would imply lower sustainable harvest rates compared to the perception in The consequences of this change in perception is a stock that has a risk of about 10% of being unable to sustain itself above 1.24 Mt (the current proxy reference point for B lim), even with no fishing. These aspects (appropriateness of reference points and robustness of the selectivity in the assessment) need to be examined in more detail before parameterization of an alternative HCR can be carried out. Suggestions Future work could focus on: Benchmarking the stock assessment and the reference points; Simulations similar to the ones reported here, but with revised assessment and reference points; Stakeholder involvement in refining the tradeoff between various possibilities. Basis of the advice Building upon previous work, ICES carried out a review of some elements of the HCR at a workshop in June 2013 (ICES, 2013a). This workshop addressed the following concerns raised in relation to the conditioning of the simulation and the construction of the HCR: a) appropriate modelling of recruitment; b) the scenario of successive years of poor recruitment; and c) the implementation of an explicit protection rule. The original simulations modelled recruitment as a single fit to a hockeystick function and did not incorporate autocorrelation in recruitment. An analysis of the timeseries (excluding the very large 1982 year class) showed significant autocorrelation at a 1year time lag. In order to conform to current standards it was necessary to include this autocorrelation so that the probability of low biomass could be correctly investigated. The autocorrelation was parameterized and applied in new simulation runs. The implementation of autocorrelation had little effect on the yield and yield variability statistics. The frequency and magnitude of interannual TAC changes were also little altered. There was, however, a significant increase in risk to the reference SSB level, with a doubling of the risk in the initial period (first ten years). A scenario of successive poor recruitment was not explicitly tested in the original simulations, although successive low recruitment could have been drawn from the recruitment function, albeit with low probability. In order to investigate the effect of sustained periods of low recruitment and the response of the harvest rule, scenarios were tested which imposed the minimum observed recruitment from the historical timeseries for periods of one, two, and three consecutive years (ICES, 2013a). The conclusion was that the HCR is not sufficiently flexible to cope with more than one successive year with the minimum estimated recruitment to date. In addition, the risk increases significantly with two or three successive years of minimum recruitment (see Table ). Table Illustration of the effect of including increasing risk (autocorrelation) for poor recruitment. In the column AC (AutoCorrelation) Y means including and N excluding autocorrelation. In the column 10Yr Per 1 stands for the tenyear period , and 2 for Risk1 is the average risk within the tenyear period and Risk 2 is the risk of falling below SSB1982 at least once in the tenyear period. It can be seen that the risk approximately doubles when autocorrelation is taken into account. Yield Risk of SSB< SSB1982 AC TACref 10yr Per Mean (kt) CV (%) Risk1 (%) Risk2 (%) Y N Y N The inertia in the original HCR and the increased stresstesting requirement result in risk values (SSB< SSB 1982) above 5% for the parameters in the HCR as defined in the plan. A protection rule was examined which takes the form of an egg count threshold limit (normally called a trigger point) below which a factor (between 0 and 1) is applied. This modification decreases the yield, based on the ratio of the observed egg count to the threshold (ICES, 2013a). The results showed that the risk could be managed through the use of different values of the threshold limit whereby higher thresholds would lower the risk, but at the cost of increased yield variability and lesser reductions in average yield. 50 ICES Advice 2013, Book 9

55 Simulations were also conducted with further modification to the HCR: an additional multiplier for the TAC. The multiplier is based on an egg limit and a divisor. For example, if the egg limit is 500 with a divisor of 500 and the egg count is 400, then the multiplier applied to the TAC is 400/500 = 0.8. With the same settings but using a divisor of 1000 would result in a multiplier of 400/1000 = 0.4, i.e. more stringent action. So, the limit sets the point at which action is taken and the divisor sets the strength of the action. Table lists various combinations of egg limit and egg divisor and Table shows the results of the simulations. Table Egg limits and divisors for the protection rules investigated. HCR Egg limit Egg divisor 1 NA NA Table Results of simulations with the various protection rules from Table The simulation results are shown for the HCR and the two risk options in the future first (1 10), second (11 20), and third (31 40) tenyear periods. HCR Yield 1 10 Risk Risk Yield Risk Risk Yield Risk Risk % 70% % 58% % 39% % 69% % 54% % 28% % 71% % 52% 164 9% 24% % 68% % 48% 163 9% 23% % 66% % 43% 154 6% 16% % 59% 74 10% 30% 135 2% 6% % 49% 96 10% 30% 132 2% 7% % 32% 57 4% 12% 92 0% 1% % 41% 79 6% 20% 107 1% 3% % 28% 39 3% 10% 62 0% 0% Effect of the changes in the perception of the stock, the stock productivity, and the effect of the future fishery on the stock The analyses suggest that in its original form the HCR would not meet the minimum criteria to satisfy a precautionary approach. This is primarily because in the original tests, recruitment was not modelled adequately. The original HCR is not robust to scenarios of successive poor recruitment and requires strengthening in the form of a protection rule. In the evaluation so far the original model conditioning has been addressed through the inclusion of autocorrelation in recruitment. These elements were then tested with the introduction of a protection rule in the HCR. The Management Plan workshop report (ICES, 2013a) presents examples of parameters for these amendments to the HCR. However, the perception of risk associated with the HCR depends also on the productivity of the stock and the effect of the future fishery on the stock. These aspects have not yet been fully explored. The perception of both of these aspects (from the 2011 assessment) has changed considerably from the view on which the original simulations were based. The selection in the fishery was lower on young fish in 2006, but in 2011 the selection is estimated by the assessment to be very high on young fish (1.5 to 2 times that on older fish) and decreasing on older fish (Fig ). Also, a comparison of the stock and recruitment pairs shows that the current perception of productivity is more variable than it was in 2006 (Figure ). ICES Advice 2013, Book 9 51

56 Figure Comparison of the results of the assessments carried out in 2006 and 2011, in terms of exploitation pattern sa (i.e. relative fishing mortality) by age in the left panel, and in terms of recruitment against SSB in the right panel. Please note that the exceptional 1982 year class is not included. With no agestructured population index, there is no independent information in the assessment to rationalize increased numbers of young fish in the catches. Currently, these observations are described by the assessment model as increased selection on young fish, though an alternative possibility is that these data are the result of increased recruitment, with unchanged fishery selection. In general terms the view from the 2011 assessment implies that the stock is less productive (at least recently) and that the productivity is harvested earlier by the fishery, which in turn would imply sustainable harvest rates that are lower from the 2011 point of view than the perception in Figure illustrates the implication of the differences in conditioning based on the 2006 and 2011 assessments. For comparative purposes both simulations did not include the 1982 year class in the data and also did not include autocorrelation in recruitment (although autocorrelation was included in further analyses based on the 2011 assessment). Fig shows that with the 2011 conditioning (panel B), the risk (probability of SSB >SSB 1982 after 50 years) is above 10% even with zero fishing and increases most rapidly for Fs above 0.05; MSY (around 130 kt) is achieved at an F of about With the 2006 conditioning (panel A) the risks are low (< 10%) up to Fs in the region of MSY based on the 2006 conditioning (around 200 kt) is achieved at an F around It can also be seen that in both cases that maximum yield is achieved with risks in the region of 50%. A B Figure Longterm stochastic yield and risk plots for western horse mackerel. Plots of risk (called Risk 3 on the secondary yaxis in the plots) and yield against F for simulations conditioned on the 2006 (panel A) and 2011 (panel B) assessments. The yield is shown as mean, median, and with 10 th and 90 th percentiles. The risk is calculated after 50 years run time, based on 1000 iterations for each step of F (0.01). 52 ICES Advice 2013, Book 9

57 Sources ICES. 2014a. Report of the Workshop to evaluate the EU management plan for Western horse mackerel (WKWHMAC), June 2013, ICES Headquarters, Copenhagen. ICES CM 2013/ACOM:59. ICES. 2013b. Report of the Workshop on Guidelines for Management Strategy Evaluations (WKGMSE), January 2013, ICES Headquarters, Copenhagen, Denmark. ICES CM 2013/ACOM: pp. ICES Advice 2013, Book 9 53

58 Appendix Excerpt of harvest rules from the European Commission's Western horse mackerel management proposal Article 5 Procedure for setting the TAC 1. In order to achieve the objective laid down in Article 4, each year the Council, acting in accordance with the procedure laid down in Article 20 of Council Regulation (EC) No. 2371/2002 and after consultation of the STECF, shall decide on the TAC for western horse mackerel for the following year. 2. The TAC shall be set in accordance with this Chapter. Article 6 Calculation of the TAC 1. The TAC shall be calculated by deducting from the total removal calculated in accordance with Articles 7 and 8 a quantity of fish equivalent to the discards, including slipped fish, having occurred in the year preceding the year in which the latest scientific assessment has been made, as estimated by STECF. 2. Where the STECF is not able to estimate the level of discards including slipped fish for the year preceding the year in which the latest scientific assessment has been made, the deduction shall be equal to the highest relative amount of discards including slipped fish scientifically estimated as having occurred within the last 15 years, but not lower than 5%. 3. Where the TAC is calculated on the basis of the total removal calculated provisionally in accordance with Article 7(3), it shall be adapted during the year of its application to the final calculation of the removal. Article 7 Calculation of the total removal for a year following an egg survey 1. Where the TAC is to be set for a year that follows a year in which an egg survey has been carried out, the total removal shall be calculated on the basis of the following elements: a) a constant factor equal to 1.07, reflecting a final increase of the total removal as simulated in underlying mathematical models that aims at maximising the annual yield without compromising the objective of keeping the risk to stock size decline at a very low level; b) the TAC set for the year in which the egg survey was carried out, hereinafter referred to as "reference TAC"; c) a weighting factor set in accordance with the Annex, reflecting the trend in stock abundance on the basis of egg survey indices; d) a minimal total removal amount, including estimates of discards, of tonnes. 2. The total removal referred to in paragraph 1 shall be calculated in accordance with the following formula: 1.07 * ( tonnes + (reference TAC * weighting factor) / 2) 3. Where only a provisional calculation of the latest egg survey index is available, the total removal shall be calculated in accordance with paragraphs 1 and 2 based on the provisional index and adapted during the year of application of the relevant TAC to the final result of the egg survey. Article 8 Calculation of total removal for subsequent years 1. Where the TAC is to be set for a year that does not follow a year in which an egg survey has been carried out, the total removal shall be equal to the total removal calculated for the previous year. 2. However, if more than three years have expired since the last egg survey, calculated from the year for which the TAC is to be set, the total removal shall be reduced by 15%, unless STECF advises that such a reduction is not appropriate, in which case the total removal shall be equal to the previous one or calculated with a lower reduction, based on the advice of STECF. 54 ICES Advice 2013, Book 9

59 Calculation of the weighting factor The weighting factor is calculated as follows: a) If the slope of the last three egg survey indices is equal to or smaller than 1.5, the weighting factor is 0; b) If the slope of the last three egg survey indices is bigger than 1.5 and smaller than 0, the weighting factor is equal to 1 + ( 2/3 * the slope); c) If the slope of the last three egg survey indices is equal to or bigger than 0 and not bigger than 0.5, the weighting factor is equal to 1 + (0.8 * the slope); d) If the slope of the last three egg survey indices is bigger than 0.5, the weighting factor is 1.4. The slope is calculated from the three latest available egg survey indices. The egg survey index means the estimated number of horse mackerel eggs resulting from the triennial international egg survey for mackerel and horse mackerel in the Atlantic, divided by ICES Advice 2013, Book 9 55

60 Special request, Advice October 2013 ECOREGION SUBJECT Widely distributed and migratory stocks NEAFC request on effects on assessments of historical unaccounted landings for mackerel and the utility of new and existing surveys Request The Coastal States refer to the ICES advice on Northeast Atlantic mackerel for 2013 where it states that Unreported catches in the timeseries cause underestimation of stock size in the analytical assessment, which is the basis of the scientific advice. The level of misreporting may have changed over time. This will remain a problem for future years, as the model cannot compensate for an unknown level of historical unreported catches. (ICES Advice 2012, Book 9, pg. 9). Based on this: Advice 1. ICES is requested to explore and evaluate the sensitivity of the current assessment to past uncertainties in the estimates of removals. 2. In anticipation of the 2014 benchmark assessment, ICES is further requested to advise on the utility of existing surveys for other stocks to derive tuning indices for the mackerel assessment, or how existing mackerel surveys should be extended or improved. Furthermore, ICES is asked to advise on the need for other fisheriesindependent indices with the aim of improving the assessment. WGWIDE carried out a thorough analysis of the potential levels of underreporting over time and the sensitivity of the assessment to this uncertainty (Annex 3 in ICES, 2013c). The assessment showed sensitivity to such uncertainty, resulting in higher biomass with higher historical catch estimates. ICES decided to reject the assessment as a basis for advice. As a consequence, the advice is now based on the on recent landings, but this advice is seen as a temporary interim measure. ICES will attempt to incorporate more stock size information in an appropriate assessment model at the benchmark in Should this approach be unsuccessful a DLS approach will be developed based specifically on the triennial regime of survey data. The upcoming benchmark (WKPELA 2014) will explore alternative modelling approaches that can better deal with catch uncertainty. The work done by WGWIDE (ICES, 2013c) and knowledge gained should be considered during the benchmark process. In preparation for the 2014 benchmark assessment an issue list has been compiled, listing the types of tuning indices that could provide information from surveys that would be useful for consideration in the benchmark. The potential survey indices are: SSB index from existing egg survey timeseries Potential recruitment indices from: 1. IBTS Q1 surveys in the eastern Atlantic 2. IBTS Q4 surveys in the eastern Atlantic 3. The IESSNS Agestructured adult indices from: 1. IBTS Q1 surveys in the eastern Atlantic 2. IBTS Q4 surveys in the eastern Atlantic 3. The IESSNS 4. Acoustic survey indices from various surveys 5. Larvae index from CPR surveys 6. Tagging surveys (with recovery from the commercial fisheries) Of these existing survey series, only the egg survey is presently used in the assessment. Some of the other indices have been evaluated, and either been rejected because they do not perform adequately (within the scope of the current 56 ICES Advice 2013, Book 9

61 assessment model), or they are relatively new and the ICES process is to include new information only at the benchmarking process which has not occurred yet. In February 2013 the Workshop on Northeast Atlantic Mackerel monitoring and methodologies including science and industry involvement (WKNAMMM) was convened to assess potential contributions of fisheries to data collection for NEA to evaluate new survey methodologies for NEA mackerel. Table 2 in the WKNAMMM report (ICES, 2013b) provided an overview of some mackerelrelated surveys including methodology used, time, frequency, years, area, applicability to assessment, challenges, and potential use in the assessment for mackerel. An ICES survey methodology workshop (WGISDAA) has reviewed the IESSNS survey and provided recommendations which need to be addressed in order to create a potential stock index from this survey. ICES advises that there is a need for a reliable agestructured fisheriesindependent index for NEA mackerel stock assessment. Such an index should facilitate tracking of the relative abundance of year classes over time with acceptable accuracy and precision. ICES notes that a timeseries of at least five years would be required for this index to contribute meaningfully to an agebased assessment. Three such potential indices are currently available. The utility of all of the survey indices listed above to the mackerel assessment will be (re)evaluated at the 2014 benchmark workshop. It is not possible to say which of these surveys will be included in the benchmarked assessment in advance of that process. Sources ICES. 2013a. Report of the Ad hoc Group on the Distribution and Migration of Northeast Atlantic Mackerel (AGDMM). ICES CM 2013/ACOM: pp. ICES. 2013b. Report of the Workshop on Northeast Atlantic Mackerel monitoring and methodologies including science and industry involvement (WKNAMMM). ICES CM 2013/SSGESST:18. 37pp. ICES. 2013c. Report of the Working Group on Widely Distributed Stocks (WGWIDE), 27 August 02 September 2013, ICES Headquarters, Copenhagen. ICES CM 2013/ACOM:15. ICES. (In press). Improving the Use of Survey Data for Assessment and Advice (WGISDAA). ICES Advice 2013, Book 9 57

62 Special request, Advice October 2013 ECOREGION SUBJECT Widely distributed and migratory stocks EC request to ICES to evaluate the proposed longterm management plan for boarfish and possible inyear revision of the TAC for 2013 Advice summary ICES has not fully evaluated the proposed longterm management plan for boarfish. However, ICES identifies that Tier 1 of the proposed plan coincides with the ICES generic approach to giving advice for datarich situations. Given that a Category 1 assessment is now being used for advice, ICES recommends that Tier 1.1 of the plan be considered consistent with the PA and MSY approaches for as long as a Category 1 assessment is available. An inyear TAC revision is not possible at the moment because the 2013 assessment is the first that is of sufficient quality to be used for advice. An inyear revision would require an accepted 2012 assessment, and this was not available. Request The Pelagic RAC has proposed a management plan for the stock of boarfish. This plan includes a stability factor. The TAC for boarfish 2013 was set by the Council at 82,000 t, in line with the advice. Council and Commission committed to ask for a scientific evaluation of the plan and to revise the TAC according to the plan if the plan is evaluated as being precautionary. ICES is therefore requested to evaluate the proposed multiannual management plan for boarfish as proposed by the pelagic RAC. Elaboration on ICES advice ICES compliments the Pelagic RAC on developing this plan. The plan can deal with various levels of data availability, from a full Category 1 ICES assessment to completely data deficient. There is a decision rule to match every state of information availability, including when no information is available. Evaluation of the management plan After the end of the recent WGWIDE, there was insufficient time available to conduct the simulations required to evaluate the plan. However, ICES notes that the ICES advice for 2014 is consistent with Point 1.1 of the plan. ICES advises that as long as the boarfish assessment is classified as Category 1, then Tier 1 of the plan may be considered to be in conformity with the MSY approach. ICES notes that the plan includes provisions for a stability factor. In a new, developing fishery, management should be as reactive as possible to information from changing stock perceptions, especially negative perceptions. Therefore, ICES advises that the TAC constraint should either be set at zero, or be set at zero in cases of advised decrease in TAC. If the latter option is taken, then a small stability factor (e.g %) could be appropriate in the event of an advised TAC increase. This would enable management to react to the fullest extent to decreasing stock signals, yet be less reactive to possible TAC increases. The remaining harvest control rule terms of the proposed management plan cannot be evaluated at the moment. ICES policy is to use the datalimited stocks (DLS) approach in the absence of a Category 1 assessment. However, the subsequent terms of the proposed management plan might be followed, if they resulted in more precautionary management (lower TACs) than those provided for in the DLS approach, and if a Category 1 assessment ceased to be available in the future. There is also an area closure which is a useful way of protecting other species, as well as a seasonal closure that aims to minimize the bycatch of mackerel. Both of these clauses are considered to be welcome additions to the plan. It might be useful to include a proviso to iteratively adapt these measures as new information becomes available on bycatches of other species. Inyear revision An inyear revision of the TAC is not possible in The request requires that a full management strategy evaluation (MSE) be performed as a basis for considering such a revision, and such an MSE is not currently possible. An inyear 58 ICES Advice 2013, Book 9

63 revision would require a forecast based on the assessment that was available at the end of This assessment was not used as a basis for advice in 2013 because certain aspects of the model required development. As such the 2012 assessment cannot be a basis for an inyear TAC revision. In 2013, ICES conducted a new assessment that is an improvement on the 2012 assessment. The new assessment incorporates catches and a timeseries of trawl surveys up to the end of 2012, an acoustic survey in 2012, and an inyear acoustic survey in This system does not allow an inyear revision because in the assessment configuration, 2013 is an intermediate year. An inyear revision based on the current assessment configuration would thus involve a truncation of the 2year acoustic series, leaving only a single acoustic abundance estimate. This is insufficient for the current assessment to function. With the resources available to ICES, the priority was to achieve a Category 1 assessment and forecast. This assessment/forecast is consistent with the main provision of the proposed plan. ICES also notes that the proposed plan does not mention an inyear revision. ICES considers this appropriate because caution should be a paramount consideration in a developing fishery. Inyear TAC revisions lacking the best quality information and sufficient time for its evaluation would not be a prudent course of action in developing fisheries. ICES Advice 2013, Book 9 59

64 Special request, Advice October 2013 ECOREGION SUBJECT Widely distributed and migratory stocks NEAFC request to ICES to evaluate the extra harvest control rule options for the longterm management plan for blue whiting Advice summary ICES reaffirms the precautionary reference points given in its response of June 2013 to the special request from NEAFC on the longterm management plan for blue whiting, (Section ). ICES confirms that the value of F 0.1 is currently estimated to be ICES advises that the value of F MSY is considered to be 0.30 and this replaces the F 0.1 proxy for F MSY of 0.18 from the advice of September 2012 (Section 9.4.4). For the fixed target Fs of 0.22, 0.25, and 0.30 the HCRs are shown to meet the ICES precautionary requirements of less that 5% probability of SSB< B lim over a tenyear period. The proposed multistage HCRs are shown to meet the ICES precautionary requirement of less that 5% probability of SSB< B lim for the recruitment regimes simulated over a 40year period (12 years of normal recruitment followed by 8 years of high recruitment and, finally, followed by 20 years of low recruitment). The request proposes a new multistage HCR with two optional values for a slope parameter (a2). The results of the evaluations showed that the HCRs gave similar performance with both values and no differences could be seen in the plots of SSB and F. The increase in F at high biomass leads to greater catch variability and 4% higher yields over the 40year period simulated (particularly during periods of high recruitment). The multistage HCR leads to higher interannual variability (IAV) in TAC during the period of declining stock as recruitment changes from the high to the low regime. IAV for the multistage HCR is 33% compared to 25% for the F target of Two extreme cases of banking and borrowing were evaluated (either continually banking or borrowing the full allowable amount). Both showed negligible differences in terms of F, SSB, or probability of SSB< B lim. The advice for TAC levels (2014) according to the different target F options (0.22, 0.25, and 0.30) outlined in this request were also provided in the advice issued in October 2013 (Section 9.4.5). For the multistage HCR with either slope option the target F for 2014 is 0.30, which is also provided as a catch option in the October 2013 Advice. Request ICES delivered an advice to a special request from NEAFC on blue whiting management strategy in June 2013 (ICES, 2013a). This advice was presented by ICES at the NEAFC PECMAS meeting in June Following some discussion by PECMAS it was concluded that a few elements would be good to have further clarified and a few more scenarios would be useful to get tested. Therefore, NEAFC forwarded the following request to ICES: ICES is requested: 1) To advise on whether the precautionary and MSY reference points given in its response of June 2013 to the special request from NEAFC on the long term management plan for blue whiting, are considered to be valid, in particular a) That the value of F0.1 is considered to be 0.22 rather than 0.18, as stated in the advice of September 2012 b) That the value of Fmsy is considered to be 0.30 rather than 0.18, as stated in the advice of September ) To confirm whether the current harvest control rule with three different F targets, 0.22, 0.25 and 0.30, is precautionary. In addition ICES is requested to evaluate the F targets referred to in this point with an interannual quota flexibility of +/ 10 %. 3) To evaluate the proposed HCR form, as referred to in its response of June 2013, with the parameters shown below Figure 1, and with an interannual quota flexibility of +/ 10%. 60 ICES Advice 2013, Book 9

65 A lower bound of F= 0.05 below Blim = tonnes; A linear sliding scale with slope a1 starting at Blim and ending at Trigger B1 = tonnes; A standard level between Trigger B1 and Trigger B2 at ICES best estimate of F0.1; A linear sliding scale with slope a2 above Trigger B2, where Trigger B2 is tonnes; and An upper bound at higher stock sizes at ICES best estimate of Fmsy. The evaluations should be done using values for the slope a2 of 2.0 and 3.0 as defined in table of the ICES response of June ICES is also invited to suggest alternative values of the slope if these would be more precautionary or reduce interannual TAC variability. 4) To compare and tabulate the results in 2 and 3, as well as result of the current HCR, on the basis of effects on longterm development of stock size, interannual variability in the catch and probability of stock size falling below Btrigger (B1). ICES is requested to deliver its advice together with its October 2013 advice on widely distributed stocks. ICES is also requested to give advice for TAC levels (2014) according to the different options outlined in this request. In the text below, current HCR refers to harvest control rules that exclude Trigger B2, Slope a2, and the upper bound (i.e. includes everything to the left of Trigger B2 in Figure 1 of the request). Proposed multistage HCR refers to HCRs that include all the elements contained in Figure 1 in the request. Elaboration on the advice An improved version has been developed of the analysis tool HCS program for simulating harvest control rules (Version HCS13_4) using previous analyses (ICES, 2013a). Software description and instructions for users are available from the ICES Secretariat. The previous approach assumed knowledge of the current recruitment regime; however, this information would not be available in practice. Therefore, the simulations given here are based on shortterm forecasts being based on the geometric mean of perceived recruitments from year 5 to year 2, relative to the intermediate year. The new evaluations also include a higher observation error (CV increased from 0.24 to 0.30) to account more completely for uncertainty in the assessment. Previous analyses only included assessment model errors. The simulations evaluate the proposed HCR by assuming a normal high low recruitment scenario, i.e. a normal recruitment for a period of 12 years until the regime shifts to high recruitment for a duration of eight years, followed by a low recruitment period until the end of the time period in the analyses year 2052 (see Figure ). This specific regime was chosen as it was thought it would give a suitable test for the multistage HCR. Low recruitment has not previously been observed for a period of longer than five years, so the simulation of low recruitment for 20 years was considered a worstcase scenario and likely an extreme test. Thus, the risk of SSB being below B lim in the period , estimated to be greater than 5% in some of the simulations, is likely to be an overestimate. Therefore, the results for this period are not included in considerations of the ICES precautionary criteria. ICES Advice 2013, Book 9 61

66 Reevaluation of reference points The results of the new analysis are consistent with the precautionary and MSY reference points given by ICES in June and October 2013 (ICES, 2013a, 2013b). Evaluation of options for HCRs Following the overall approach used by ICES in June 2013 (ICES, 2013a) ICES has evaluated some additional HCR scenarios to answer the request above (ICES, 2013c). Summary performance statistics in terms of the development of stock size, interannual variability in the catch, and probability of stock size falling below Trigger B1 of all the HCRs evaluated for this request are provided in Table The results for runs that include banking or borrowing are not shown because there is little difference in the performance statistics. Basis of the advice Background A management plan was agreed by Norway, the EU, the Faroe Islands, and Iceland in 2008 (ICES, 2012b). The plan uses: i) a target fishing mortality (F = 0.18) if SSB is above SSB MP (= B pa), ii) a linear reduction to F = 0.05 if SSB is between B pa and B lim, and iii) F = 0.05 if SSB is below B lim. In order to facilitate discussions between Coastal States on possible modifications to the longterm management plan for blue whiting in the Northeast Atlantic, ICES was requested by NEAFC to conduct an evaluation of the harvest control rule elements under the existing longterm management plan (ICES, 2013b). ICES provided a response in June 2013 (ICES, 2013a) and following that advice, NEAFC requested a few further options to be evaluated, as outlined in the request description above. Results Reference points The new data were consistent with the data used by ICES in June 2013 in terms of weightatage, maturityatage, and exploitation pattern. The small revision of the software tool used did not result in different estimates of F 0.1 or F MSY compared to those presented by ICES in June Proposed HCR Harvest control rule with F targets (0.22, 0.25 and 0.30) The request required the evaluation of the current HCR with alternative F targets (0.22, 0.25, and 0.30). Figure shows the performance of these alternatively parameterized HCRs compared with the current HCR (F = 0.18). Realised F values differ from the target F values due to observation and model errors included in the setting of the TAC (i.e. imperfect information from the true population) and because the stock often falls below the Trigger B1 under normal and low recruitment regimes. At the beginning of the high recruitment period F values decrease sharply since recruitment has increased, but as this would be unknown at the start of the high recruitment period it is not yet accounted for in the TAC setting procedure This assumes recent threeyear average recruitment in the forecast. Conversely for similar reasons, F values increase when the recruitment regime changes from high to low. Under the low recruitment regime at the end of the time period, for all F target values the stock stabilizes at a level below the Trigger B1, leading to lower Fs. These lower Fs allow the stock to stabilize above B lim on average for all F targets. As the stock increases under the high recruitment regime, the higher target Fs result in higher TACs and restrict stock growth. Under lower target Fs, since the stock reaches a larger size this results in slightly higher TACs when the stock decreases after the change in regime from a high to a low recruitment. Under the normal and high recruitment periods the maximum annual probability of SSB< B lim is less than 5% (Figure ). However, after seven years of the low recruitment the probability of SSB< B lim exceeds 5% when an F target of 0.30 is used. This risk increases to 8 9% over the last ten years of the simulation. Likewise, an F target of 0.25 leads to a greater than 5% probability of SSB< B lim in 62 ICES Advice 2013, Book 9

67 the last ten years of the simulation. Low recruitment has not previously been observed for a period of longer than five years, so this worstcase scenario which simulates low recruitment for 20 years is likely to be an extreme test. However, considering the low likelihood of consistently low recruitment and that densitydependent growth and maturity as well as cannibalism are not accounted for in the present analysis, the actual risks are expected to be smaller. Thus, the risk of SSB being below B lim in , estimated to be greater than 5% in some of the simulations, is likely to be an overestimate. Therefore, this aspect is not included in considerations of ICES precautionary criteria. Banking and borrowing Banking and borrowing was found to have a very limited effect for all alternative F targets (Figures and 4). Figure shows the performance of the HCR with an F target of 0.30 compared to the same HCR under scenarios of constant banking and constant borrowing. The most notable difference comes following the change from a high recruitment period to a low recruitment period. A scenario of constant banking leads to a delay in the reduction of TACs, leading to slightly higher F values and slightly lower SSB values. A similar pattern is seen for all alternative F target values (results not shown here). For higher F targets, after a sustained period of low recruitment there is a slightly higher but negliglible probability of SSB< B lim under constant banking and a slightly lower probability of SSB< B lim under constant borrowing (Figure ). Proposed multistage HCR The request proposed specific parameters of the new HCR. The evaluations were done using these parameters, with values for the slope a2 of 2.0 and 3.0 (Figures and ). These two slope values perform almost identically (the lines overlap in Figure ). The proposed rule leads to higher Fs at all stock sizes compared to the current HCR. When SSB is greater than Trigger B2 (4000 kt) the proposed rule leads to higher Fs and TACs and lower SSB. Following the transition from a high recruitment regime to a low one, the current HCR provides higher TACs since the F values are reduced to similar levels for both HCRs while the stock size is allowed to be larger during the periods of high recruitment under the current HCR. After a period of sustained low recruitment, the probability of SSB< B lim is slightly higher under the proposed HCR than the current HCR (Figure ). However, even under this unlikely scenario of sustained poor recruitment, the maximum annual probability of SSB< B lim remains below 5% for both rules. The reason for the minor difference between the two different slope options is that they are both rather steep and that the F of the HCR switches very quickly from 0.22 to Methods The main differences from the approach used in June 2013 (ICES, 2013a) were the higher observation error and the decision process where recruitment predictions in the shortterm forecast were different. In June 2013 these were according to a deterministic stock recruitment function, with parameters representing the regime at the beginning of the projection period which was not realistic. To address this issue, the present simulations are based on the geometric mean of perceived recruitments from year 5 to year 2, relative to the intermediate year. Sources ICES. 2012a. Report of the Working Group on Widely Distributed Stocks (WGWIDE), August 2012, Lowestoft, UK. ICES CM 2012/ACOM: pp. ICES. 2012b. Blue whiting in Subareas I IX, XII, and XIV (Combined stock). In Report of the ICES Advisory Committee ICES Advice, 2012, Book 9: ICES. 2013a. NEAFC request to ICES to evaluate the Harvest Control Rule element of the longterm management plan for blue whiting. In Report of the ICES Advisory Committee ICES Advice, 2013, Book 9, Section ICES. 2013b. Blue whiting in Subareas I IX, XII, and XIV (Combined stock). In Report of the ICES Advisory Committee ICES Advice, 2013, Book 9, Section ICES. 2013c. ICES Ad Hoc Group on blue whiting management plan evaluations. Authors: David C. M. Miller and Dankert Skagen. ICES CM 2013/ACOM:76. ICES Advice 2013, Book 9 63

68 Figure Mean performance of the current management plan HCR with F target options of 0.18, 0.22, 0.25, and 0.3 under the changing recruitment scenario of normal (ten years), high (eight years), and low (20 years) recruitment. No banking or borrowing is included. Figure Annual probability of SSB< Blim for the current management plan HCR with alternative F target options of 0.18, 0.22, 0.25, and 0.3 under the changing recruitment scenario of normal (ten years), high (eight years), and low (20 years) recruitment. No banking or borrowing is included. 64 ICES Advice 2013, Book 9

69 Figure Mean performance of the current management plan HCR with an F target option of 0.3 under the changing recruitment scenario of normal (ten years), high (eight years), and low (20 years) recruitment. Figure Annual probability of SSB< Blim for the current management plan HCR with alternative F target options of 0.18, 0.22, 0.25, and 0.3 under the changing recruitment scenario of normal (ten years), high (eight years), and low (22 years) recruitment. No banking or borrowing is included. ICES Advice 2013, Book 9 65

70 Figure Performance of the proposed HCR compared to the current HCR under the high recruitment scenario. (Normal and low recruitment are not relevant here these scenarios are illustrated above (Figure ) because the stock seldom gets above Trigger B2.) The proposed HCR is: F = 0.05 below Blim (1500 kt), Trigger B1 = 2250 kt, standard F = 0.22 between Trigger B1 and Trigger B2, Trigger B2 = 4000 kt, and F increases to an upper bound of F = 0.30 along a slope a2 = 3 (red) or a2 = 2 (blue). Note that the blue line is overshadowed by the red line in each plot because the results are almost identical. Figure Performance of the proposed HCR compared to the current HCR under high recruitment scenario. The proposed HCR is: F = 0.05 below Blim (1500 kt), Trigger B1 = kt, standard F = 0.22 between Trigger B1 and Trigger B2, Trigger B2 = 4000 kt, and F increases to an upper bound of F = 0.30 along a slope a2 = 3 (red) or a2 = 2 (blue). Note that the blue line is overshadowed by the red line in each plot because the results are almost identical. 66 ICES Advice 2013, Book 9

71 Table Summary performance statistics of all the HCR evaluated for the second request. Results for runs including banking or borrowing are not shown since these performed very similarly to runs without banking or borrowing. During sustained low recruitment the stocks will on average stabilize at a level above Blim for all HCRs, though for target Fs of 0.25 and above the probability of SSB< Blim exceeds 5%. Low recruitment has not previously been observed for a period of longer than five years, so this worstcase scenario which simulates low recruitment for 20 years is likely to be an extreme test. Thus, the risk of SSB being below Blim in , estimated to be greater than 5% in some of the simulations, is likely to be an overestimate. Therefore, this aspect is not included in considerations of ICES precautionary criteria First 5 years (Short term) HCR* Catch F SSB TAC IAV % Max annual P(SSB< Blim) Max annual P(SSB< Btrigger) Current MP New MP_a2 = New MP_a2 = Last 10 years (Low recruitment equilibrium) HCR* Catch F SSB TAC IAV % Max annual P(SSB< Blim) Max annual P(SSB< Btrigger) Current MP New MP_a2 = New MP_a2 = All years (Including normal, high, and low recruitment periods) HCR* Catch F SSB TAC IAV % Max annual P(SSB< Blim) Max annual P(SSB< Btrigger) Current MP New MP_a2 = New MP_a2 = *No banking or borrowing. ICES Advice 2013, Book 9 67

72 9.4 Stock summaries Advice June 2013 ECOREGION STOCK Widely distributed and migratory stocks Alfonsinos/Golden eye perch (Beryx spp.) in the Northeast Atlantic Advice for 2014 The advice given in 2012 for alfonsinos/golden eye perch (Beryx spp.) assessment units is biennial and valid for 2013 and 2014 (see ICES, 2012). The advice is summarized in the table below. Sources ICES Alfonsinos/Golden eye perch (Beryx spp.) in the Northeast Atlantic. Report of the ICES Advisory Committee, ICES Advice, Book 9: Table Alfonsinos in the Northeast Atlantic. ICES advice, management, and landings. Year ICES Advice 2003 Fishery should not be allowed to expand, unless proven to be sustainable and accompanied by programmes to collect data on by(catch) Predicted catch corresp. to advice TAC EU 1 ICES landings 2004 Biennial Fisheries accompanied by programmes to collect data on by(catch) 2006 Biennial Fishery should not be allowed to expand, unless proven to be sustainable 2008 Biennial Fishery should not be allowed to expand, unless proven to be sustainable 2010 Biennial Fisheries should not be allowed to expand, and a reduction in catches should be considered 2012 No new advice, same as % Reduction in catches (last 3 years average) No new advice, same as Weights in thousand tonnes. 1 Subareas III, IV, V, VI, VII, VIII, IX, X, XII, and XIV ICES Advice 2013, Book 9

73 9.4.2 Advice October 2013 ECOREGION STOCK Widely distributed and migratory stocks Angel shark (Squatina squatina) in the Northeast Atlantic Advice for 2014 The advice given in 2012 for this stock is biennial and valid for 2013 and 2014 (see ICES, 2012a): ICES advises on the basis of the precautionary approach that there should be no catches of angel shark, and that it should remain a species prohibited from being fished. Measures should be taken to minimize bycatch. The advice is summarized in the table below. Sources ICES. 2012a. Angel shark (Squatina squatina) in the Northeast Atlantic. In Report of the ICES Advisory Committee 2012, Section ICES Advice, Book 9: ICES. 2012b. Report of the Working Group on Elasmobranch Fishes (WGEF), June 2012, Lisbon, Portugal. ICES CM 2012/ACOM: pp. Table Angel shark in the Northeast Atlantic. ICES advice, management, and landings (minimum estimate based on declared landings for Subareas VI, VII, and VIII). No landings are recorded for areas where angel shark was present in historical times. Year ICES advice TAC ICES landings No specific advice No specific advice No new advice, same as for TAC = No new advice, same as for TAC = No new advice, same as for TAC = No new advice, same as for Weights in tonnes. ICES Advice 2013, Book 9 69

74 9.4.3 Advice October 2013 ECOREGION STOCK Widely distributed and migratory stocks Basking shark (Cetorhinus maximus) in the Northeast Atlantic Advice for 2014 The advice given in 2012 for this stock is biennial and valid for 2013 and 2014 (see ICES, 2012a): ICES advises on the basis of the precautionary approach that there should be no catches of basking shark, and that it should remain a species prohibited from being fished. The advice is summarized in the table below. Sources ICES. 2012a. Basking shark (Cetorhinus maximus) in the Northeast Atlantic. In Report of the ICES Advisory Committee 2012, Section ICES Advice, Book 9: ICES. 2012b. Report of the Working Group on Elasmobranch Fishes (WGEF), June 2012, Lisbon, Portugal. ICES CM 2012/ACOM: pp. Table landings. Basking shark in the Northeast Atlantic (ICES Subareas I XIV). ICES advice, management, and Year ICES Advice Predicted catch corresp. to advice Agreed TAC ICES landings 2006 TAC = TAC = 0, No target fishery minimize bycatch No new advice, same as for TAC = 0, No target fishery minimize bycatch 0 0 < No new advice, same as for Catch = No new advice, same as for No target fishery, TAC = No new advice, same as for Weights in tonnes. 70 ICES Advice 2013, Book 9

75 9.4.4 Advice June 2013 ECOREGION STOCK Widely distributed and migratory stocks Black scabbardfish (Aphanopus carbo) in the Northeast Atlantic Advice for 2014 The advice given in 2012 for black scabbardfish (Aphanopus carbo) assessment units is biennial and valid for 2013 and 2014 (see ICES, 2012). The advice is summarized in the table below. Sources ICES Black scabbardfish (Aphanopus carbo) in the Northeast Atlantic. Report of the ICES Advisory Committee, ICES Advice, Book 9: Table Black scabbardfish in the Northeast Atlantic. Summary of advice for different assessment units and landings. Year ICES advice Subareas VI, VII, and Divisions Vb and XIIb 2003 Significant effort reduction ICES advice Subareas VIII and IX ICES advice Other areas 1 ICES landings All areas Status quo exploitation Status quo exploitation level 8.4 level 2004 Biennial Biennial Biennial Significant effort reduction Status quo exploitation level Fishery should not be allowed to expand, unless proven to be 7.3 sustainable 2006 Biennial Biennial Biennial Constrain catches to Status quo exploitation Fishery should not be allowed to tonnes level expand, unless proven to be sustainable 2008 Biennial Biennial Biennial Constrain catches to Constrain catches to Fishery should not be allowed to tonnes average expand, unless proven to be sustainable 2010 Biennial Biennial Biennial Same advice as Same advice as 6.0 previously previously 2012 No new advice, same as No more than 20% catch increase (4.7kt) Catches should not exceed 2900 tonnes 2014 No new advice, same as 2013 Weights in thousand tonnes. 1 Subareas I, II, IV, X, XIV, and Divisions IIIa and Va. Fishery should not be allowed to expand, and a reduction in catches should be considered Fisheries should not be allowed to expand until they can be shown to be sustainable ICES Advice 2013, Book 9 71

76 9.4.5 Advice October 2013 ECOREGION STOCK Widely distributed and migratory stocks Blue whiting in Subareas I IX, XII, and XIV Advice for 2014 ICES advises on the basis of the management plan agreed by Norway, the EU, the Faroe Islands, and Iceland that landings in 2014 should be no more than tonnes. All catches are assumed to be landed. Stock status MSY (FMSY) Precautionary approach (Fpa,Flim) Management plan (FMP) MSY (Btrigger) Precautionary approach (Bpa,Blim) F (Fishing Mortality) Appropriate Harvested sustainably Below target SSB (SpawningStock Biomass) Above trigger Full reproductive capacity Management plan (SSBMP) Above trigger Figure Blue whiting in Subareas I IX, XII, and XIV. Summary of stock assessment. SSB has almost doubled from 2010 (2.9 million tonnes) to 2013 (5.5 million tonnes) and is well above B pa (2.25 million tonnes). This increase is due to the lowest Fs in the timeseries in 2011 and 2012, in combination with increased recruitment since ICES Advice 2013, Book 9

77 Management plans A management plan (Section Annex) was agreed by Norway, the EU, the Faroe Islands, and Iceland in The plan uses i) a target fishing mortality (F = 0.18) if SSB is above SSB MP (= B pa), ii) a linear reduction to F = 0.05 if SSB is between B pa and B lim, and iii) F = 0.05 if SSB is below B lim. ICES evaluated the plan in 2008 and concluded that it is in accordance with the precautionary approach (PA; ICES, 2008). ICES evaluated a NEAFC request concerning an alternative management plan in May 2013 (ICES, 2013a) and further in October 2013 (ICES, 2013b). Biology Blue whiting is widely distributed in the eastern part of the North Atlantic from Norway to the south of Portugal, with the highest concentrations along the edge of the continental shelf between 300 and 600 m. Most spawning takes place along the shelf edge and on banks west of the British Isles. Juveniles are also widely distributed, including in the Bay of Biscay and Iberian waters, with the main nursery area believed to be in the Norwegian Sea. Environmental influence on the stock The position and strength of the North Atlantic subpolar gyre (SPG) appears to influence the spawning distribution of blue whiting (Hátún et al., 2009). The strong gyre constrains spawning distribution. This gyre may influence recruitment success through food availability and/or predation levels (Payne et al., 2012). However, these mechanisms are not fully understood and are being explored further. The fishery The main fisheries on blue whiting in 2012 were conducted west of Scotland, around the Porcupine Bank, and south of the Faroe Islands. Most blue whiting catches occurred in the first half of the year. Catches have become increasingly used for human consumption rather than industrial purposes. Catch distribution Total landings (2012) = 384 kt (mainly pelagic trawl). Discards are considered negligible. Effects of the fisheries on the ecosystem Blue whiting feed on zooplankton and small fish in the same areas as herring and mackerel, but at greater depth. Quality considerations The principal survey for the adult part of this stock conducted in 2013 had high quality coverage of the survey area in space and time and is considered to have provided good quality data. Incoming recruitment is poorly estimated due to a lack of juvenile indices suitable for inclusion in the assessment model. The new modelling framework used is likely to result in more stable assessments than in previous years. Figure Blue whiting in Subareas I IX, XII, and XIV. Historical assessment results. Horizontal lines represent reference points. ICES Advice 2013, Book 9 73

78 Scientific basis Assessment type Input data Discards and bycatch Indicators Other information Working group report Agebased analytical (SAM). Commercial catches from international landings, ages and length frequencies from catch sampling. One survey index (International blue whiting spawning stock survey (IBWSS) , excluding 2010). No commercial indices. Annual maturity data from fixed values, estimated in 1994 by combining maturity ogives from the southern and northern areas. Natural mortalities fixed at 0.2, derived in the 1980s from age compositions before the industrial fishery started. Discards are not included and assumed negligible. Not used. The stock was benchmarked in February 2012 (ICES, 2012b). WGWIDE (ICES, 2013c). 74 ICES Advice 2013, Book 9

79 9.4.5 Supporting information October 2013 ECOREGION STOCK Widely distributed and migratory stocks Blue whiting in Subareas I IX, XII, and XIV Reference points Management plan MSY approach Type Value Technical basis SSB MP 2.25 million t B pa F MP 0.18 Management strategy evaluation conducted in 2008 (Anon., 2008; ICES, 2008). MSY B trigger 2.25 million t B pa (ICES, 2013a). F Yield per recruit (ICES, 2013a, 2013c). F MSY 0.30 Simulations in 2013 (ICES, 2013a). Precautionary B lim 1.50 million t Approximately B loss (confirmed by ICES, 2013a). approach B pa 2.25 million t B lim exp(1.645 σ), with σ = F lim 0.48 Equilibrium stochastic simulations (ICES, 2013a). F pa 0.32 Based on F lim and assessment uncertainties (ICES, 2013a). (unchanged since: 2013) F MSY = 0.30 gives a high yield and a low risk of SSB< B lim. Outlook for 2014 Basis: F(2013) = 0.14 (catch constraint = 643 = TAC). SSB(2014) = R(2013), R(2014), and R(2015) = GM( ) = million at age 1. Rationale Catch F SSB % SSB % TAC Basis (2014) 2014 (2015) change 1) change 2) Management plan F = 0.18 for SSB(2014) > NEAFC request 1140 Management plan, F = NEAFC request 1279 Management plan, F = NEAFC request 1502 Management plan, F = MSY framework 1502 F MSY = F pa F pa F lim F lim Zero catch F(2012) F(2012) F(2013) F(2013) Status quo F F(2013) F(2013) F(2013) F(2013) F(2013) Weights in thousand tonnes. 1) SSB 2015 relative to SSB ) Catch 2014 relative to TAC 2013 (643). Management plan The management plan agreed by Norway, EU, the Faroe Islands, and Iceland in November 2008 (see Section Annex) implies a TAC of tonnes in 2014, compared to tonnes in This is expected to lead to an increase in SSB in 2015 to 6.96 million tonnes, which is above SSB MP. The stock projection for , with uncertainties included for this option, is shown in Figure ICES Advice 2013, Book 9 75

80 MSY approach Following the ICES MSY framework implies a TAC of t in 2014 based on a fishing mortality at F MSY = This is expected to lead to a decrease in SSB in 2015 to 6.42 million tonnes, which is above MSY B trigger (2.25 million tonnes). Precautionary approach Following the ICES precautionary approach implies a TAC of tonnes in 2014 based on a fishing mortality at F pa = This is expected to lead to a decrease in SSB in 2015 to 6.33 million tonnes, which is above B PA (2.25 million tonnes). Additional considerations Management considerations The assessment shows a moderate uncertainty of the absolute estimate of F and SSB, and a higher uncertainty on the recruiting year classes. Due to good planning and favorable weather conditions the implementation of the survey in 2013 resulted in high quality data, even though the Norwegian vessel did not participate in It is essential that this survey be maintained and it is important to maintain good geographical survey coverage within the agreed time window to avoid increases in assessment uncertainty. Recruitment (age 1) is estimated significantly higher in than in the years with the historically low recruitments. The forecast and catch options for 2014 use recruitment (age 1) in 2012 from the assessment and an assumed average recruitment in A TAC derived from the target F at 0.18 (or from higher F at 0.22) from the management plan is expected to lead to an SSB well above B pa in There are uncertainties about the stock structure even though ICES (2012b) evaluated available evidence on substock structure and came to the conclusion that there is no scientific evidence in support of multiple stocks with distinct spawning locations or timings. The emerging picture is one of a single stock whose largescale spatial spread varies as a function of hydrographical conditions and total abundance; this is commonly described as an abundance occupancy relationship. Further, there seem to be a number of core nursery and feeding areas with marginal areas being occupied at times of high stock abundance. As a result, ICES considers blue whiting in ICES Subareas I IX, XII, and XIV as a single stock for assessment purposes. Data and methods The assessment is based on catchatage data from commercial catches in and one international blue whiting spawning stock survey (IBWSS) The IBWSS survey is the only survey that covers almost the entire distributional area of the spawning stock. Recruitment in the forecast is based on a qualitative analysis of trawl surveys covering parts of the distribution area for juveniles. The five available indices indicate that the 2012 year class is near average. The new information regarding the 2011 year class suggests that this is at or above average. ICES therefore decided to use the geometric mean of the whole period ( ) for the 2012 and 2013 year classes, and the estimate from the assessment for the 2011 year class (above the geometric mean). Limited information was available on discarding and discards were therefore not included in the assessment. However, discarding is considered to be minor. Comparison with previous assessment In the 2013 assessment, SSB in 2012 was estimated at 9% higher than in the previous assessment. Estimated fishing mortality in 2011 was 7% lower than in the previous assessment. The basis for advice was the same as last year. 76 ICES Advice 2013, Book 9

81 Sources Anon Report of the Working Group established by the Blue Whiting Coastal States on Blue Whiting Management Strategies, May 2008, Charlottenlund Castle, Denmark. 65 pp. Hátún, H., Payne, M. R., and Jacobsen, J. A The North Atlantic subpolar gyre regulates the spawning distribution of blue whiting (Micromesistius poutassou). Canadian Journal of Fisheries and Aquatic Sciences, 66: ICES Report of the ICES Advisory Committee, ICES Advice Book pp. ICES. 2009a. Report of the Workshop on Blue Whiting Recruitment (WKBLUR), November 2009, ICES Headquarters, Copenhagen, Denmark. ICES CM 2009/RMC: pp. ICES. 2009b. Report of the Stock Identification Methods Working Group (SIMWG). ICES CM 2009/LRC:12. ICES. 2010a. Report of the Working Group on Northeast Atlantic Pelagic Ecosystem Surveys (WGNAPES), August 2010, Hamburg, Germany. ICES CM 2010/SSGESST:20. ICES. 2010b. Blue whiting in Subareas I IX, XII, and XIV (Combined stock). In Report of the ICES Advisory Committee, ICES Advice 2010, Book 9: ICES Report of the Working Group on Northeast Atlantic Pelagic Ecosystem Surveys (WGNAPES), August 2011, Kaliningrad, Russia. ICES CM 2011/SSGESST:16. ICES. 2012a. Report of the Working Group on Widely Distributed Stocks (WGWIDE), August 2012, Lowestoft, UK. ICES CM 2012/ACOM:15. ICES. 2012b. Report of the Benchmark Workshop on Pelagic Stocks (WKPELA 2012), February 2012, Copenhagen, Denmark. ICES CM 2012/ACOM:47. ICES. 2013a. NEAFC request to ICES to evaluate the harvest control rule element of the longterm management plan for blue whiting. Special request, Advice May In Report of the ICES Advisory Committee, ICES Advice 2013, Book 9, Section ICES. 2013b. NEAFC request on additional management plan evaluation for blue whiting. Special request, Advice October In Report of the ICES Advisory Committee, ICES Advice 2013, Book 9, Section ICES. 2013c. Report of the Working Group on Widely Distributed Stocks (WGWIDE), 27 August 02 September 2013, ICES Headquarters, Copenhagen, Denmark. ICES CM 2013/ACOM:15. Payne, M. R., Egan, A., Fässler, S. M. M., Hátún, H., Holst, J. C., Jacobsen, J. A., Slotte, A., et al The rise and fall of the NE Atlantic blue whiting (Micromesistus poutassou). Marine Biology Research, 8: ICES Advice 2013, Book 9 77

82 Figure Blue whiting in Subareas I IX, XII, and XIV. Stock recruitment relationship. Figure Blue whiting in Subareas I IX, XII, and XIV. Total stock biomass and 50% and 95% confidence limits from the IBWSS survey, The SSB index from the 2010 survey was excluded from the assessment. 78 ICES Advice 2013, Book 9

83 Figure Blue whiting in Subareas I IX, XII, and XIV. Total blue whiting catches (t) in 2012 by ICES rectangle. Catches below 10 t are not shown on the map. ICES Advice 2013, Book 9 79

84 Figure Blue whiting in Subareas I IX, XII, and XIV. Stock projection following the management plan. Mean value and 95% confidence intervals are shown. 80 ICES Advice 2013, Book 9

85 Table Blue whiting in Subareas I IX, XII, and XIV. ICES advice, management, and landings. Year ICES Advice Predicted catch corresp. to advice Agreed TAC ICES catch 1987 TAC for northern areas; no advice for southern areas TAC for northern areas; no advice for southern areas TAC for northern areas; no advice for southern areas TAC for northern areas; no advice for southern areas TAC for northern areas; no advice for southern areas No advice Catch at status quo F (northern areas); no assessment for southern areas Precautionary TAC (northern areas); no assessment for southern areas Precautionary TAC for combined stock Precautionary TAC for combined stock Precautionary TAC for combined stock Precautionary TAC for combined stock Catches above t may not be sustainable in the long run F should not exceed the proposed F pa F should not exceed the proposed F pa Rebuilding plan F should be less than the proposed F pa Achieve 50% probability that F will be less than F pa Achieve 50% probability that F will be less than F pa F old management plan F should be less than the proposed F pa F should be less than F pa Maintain stock above B pa Follow the agreed management plan See scenarios Follow the agreed management plan Follow the agreed management plan Follow the agreed management plan Weights in thousand tonnes. 1 NEAFC proposal for NEAFC regions 1 and 2. 2 Agreed TAC from four Coastal States of 2 million tonnes, and an additional allocation to Russia in the international zone of t. 3 Agreed TAC from four Coastal States of 1.7 million tonnes, and an additional allocation to Russia and Greenland of t. 4 Agreed TAC from four Coastal States of 1.1 million tonnes, and an additional allocation to Russia and Greenland. 5 Agreed TAC from four Coastal States of 0.59 million tonnes, and an additional allocation to Russia (0.016 million tonnes). ICES Advice 2013, Book 9 81

86 Table Blue whiting in Subareas I IX, XII, and XIV. Landings (tonnes) by country for the period , as estimated by the Working Group. Country Denmark Estonia * Faroes France Germany Iceland Ireland Japan Latvia Lithuania Netherlands Norway Poland Portugal Spain Sweden ** UK (England)*** 1590 UK (Scotland) Russia Uanllocated 3499 TOTAL * Reported to the EU but not to the ICES WGNPBW. (Landings of tonnes). ** Imprecise estimates for Sweden: reported catch of t in 1993 is replaced by the mean of 1992 and 1994, i.e t, which is used in the assessment. *** From 2012 only UK split into England and Scotland. 82 ICES Advice 2013, Book 9

87

88 Table Blue whiting in Subareas I IX, XII, and XIV. Landings (tonnes) by main areas. Area Norwegian Sea fishery (SAs 1+2; Divs. Va, XIVa b) Fishery in the spawning area (SA XII; Divs. Vb, VIa b, VIIa c) Directedand mixed fisheries in the North Sea (SA IV; Div. IIIa) Total northern areas Total southern areas (SAs VIII+IX; Divs. VIId k) Grand total ICES Advice 2013, Book 9

89 Table Blue whiting in Subareas I IX, XII, and XIV (Combined Stock). Summary of stock assessment. Year Recruitment SSB Landings Mean F Age 1 Ages 3 7 thousands tonnes Tonnes * *SSB in 2013 is based on survivors, age 1 numbers as in 2012 and mean weightatage as in ICES Advice 2013, Book 9 85

90 Annex 1. The management plan below was agreed by Norway, the EU, the Faroe Islands, and Iceland, and endorsed by NEAFC in November The Parties agree to implement a long term management plan for the fisheries on the Blue Whiting stock, which is consistent with the precautionary approach, aiming at ensuring harvest within safe biological limits and designed to provide for fisheries consistent with maximum sustainable yield, in accordance with advice from ICES. 2. For the purpose of this long term management plan, in the following text, TAC means the sum of the coastal State TAC and the NEAFC allowable catches. 3. As a priority, the long term plan shall ensure with high probability that the size of the stock is maintained above 1.5 million tonnes (B lim). 4. The Parties shall aim to exploit the stock with a fishing mortality of 0.18 on relevant age groups as defined by ICES. 5. While fishing mortality exceeds that specified in paragraph 4 and 6, the Parties agree to establish the TAC consistent with reductions in fishing mortality of 35% each year until the fishing mortality established in paragraph 4 and 6 has been reached. This paragraph shall apply only during 2009 and For the purposes of this calculation, the fishing percentage mortality reduction should be calculated with respect to the year before the year in which the TAC is to be established. For this year, it shall be assumed that the relevant TAC constrains catches. 7. When the fishing mortality in paragraph 4 has been reached, the Parties agree to establish the TAC in each year in accordance with the following rules: In the case that the spawning biomass is forecast to reach or exceed 2.25 million tonnes (SSB trigger level) on 1 January of the year for which the TAC is to be set, the TAC shall be fixed at the level consistent with the specified fishing mortality. In the case that the spawning biomass is forecast to be less than 2.25 million tonnes on 1 January of the year for which the TAC is to be set (B), the TAC shall be fixed that is consistent with a fishing mortality given by: 8. F = [(B 1.5)*( ) / ( )] 9. In the case that spawning biomass is forecast to be less than 1.5 million tonnes on 1 January of the year for which the TAC is to be set, the TAC will be fixed that is consistent with a fishing mortality given by F = When the fishing mortality rate on the stock is consistent with that established in paragraph 4 and the spawning stock size on 1 January of the year for which the TAC is to be set is forecast to exceed 2.25 million tonnes, the Parties agree to discuss the appropriateness of adopting constraints on TAC changes within the plan. 11. The Parties, on the basis of ICES advice, shall review this long term management plan at intervals not exceeding five years and when the condition specified in paragraph 4 is reached ICES Advice 2013, Book 9

91 9.4.6 Advice October 2013 ECOREGION stocks STOCK Advice for 2014 Widely distributed and migratory Boarfish in the Northeast Atlantic Version 2, ICES advises on the basis of the MSY approach that catches in 2014 should be no more than t. If discard rates do not change from the average of the last ten years this implies landings of no more than t. Stock status F (Fishing Mortality) MSY (F MSY) Appropriate TSB (Total Stock Biomass) Quality evaluation Above possible reference point Figure Boarfish in the Northeast Atlantic. Top left panel: Catches. Bottom left panel: fishing mortality 1. Bottom right panel: Total stock biomass. No recruitment index was available from the model. Dotted lines on the total stock biomass and fishing mortality plots indicate the 95% credible interval. 1 Plot updated 22 November 2013 because Fmsy wrongly was shown at 0.30 ICES Advice 2013, Book 9 87

92 Stock status F is below F MSY and biomass is likely to be above any candidate for MSY B trigger. Management plans No specific management objectives are known to ICES. A management plan has been proposed by the Pelagic RAC, but has not yet been evaluated by ICES (see Annex). Biology Boarfish (Capros aper) is a small, pelagic, planktivorous, shoaling species, found at depths of 0 to 600 m. The species is widely distributed from Norway to Senegal, including the Mediterranean and oceanic island waters. Boarfish recruit to the fishery at around three to four years of age, although the maximum age of boarfish is about 30 years (Hüssy et al., 2012a, 2012b). Spawning occurs on the Celtic Sea shelf edge during June and July. Boarfish are asynchronous batch spawners with indeterminate fecundity and thus, under optimal conditions, are capable of spawning over an extended period of time. Maturation occurs at 3.5 years, corresponding to a total length of approximately 10 cm (Farrell et al., 2012). The maximum size of this species is about 18 cm. Boarfish does not appear to be an important prey species in the Celtic Sea area. Environmental influence on the stock Boarfish feed primarily on Calanus helgolandicus which has increased in abundance in recent years. It is suggested that the increase in abundance of boarfish observed in the EVHOE survey during the 1990s and 2000s was a result of an increase in water temperature during the spawning season which may have enhanced recruitment (Blanchard and Vandermeirsch, 2005). The fishery The fishery for boarfish is conducted with pelagic trawls. The catches are currently used for reduction to fish meal and oil, but development of a human consumption market is underway. The majority of landings to date have come from ICES Divisions VIIj (75%) and VIIh (18%) (Figure ). The recent development and expansion of the fishery was enabled by developments in the pumping technology for boarfish catches. These changes made it easier to pump boarfish ashore. The number of vessels in the fishery has been increasing, although the recent introduction of a TAC is expected to limit further effort expansion. Catch by fleet Total catch (2012) = t, including discards (8% discards in nondirected fisheries, 92% Quality considerations landings). The 2012 and 2013 acoustic survey data were considered reliable, but there is high uncertainty in the estimates of total biomass due to the short timeseries. Bottomtrawl survey indices were considered indicative of trends in their respective areas. The commercial catch data are thought to be quite complete, including discards from other fisheries from 2003 onwards. It is thought that discarding due to bycatch fisheries prior to 2003 were likely to have been small in comparison with subsequent catches. ICES considers the current basis for the advice on this stock to be an interim measure prior to development of an agebased assessment. There was concern in the appropriateness of the use of a production model in this case because the exploitation history of this stock is very short. The application of a production model to derive reference points and advice are largely dependent on model assumptions that may not hold (ICES, 2012). Scientific basis Assessment type Input data Discards and bycatch Bayesian Schaefer surplus production model. Commercial catches (international landings and discards). Two combined acoustic surveys MSHAS & BFAS; Six bottomtrawl survey indices EVHOE, Q4; IGFS, Q4; WCSGFS, Q1 and Q4; SPPGFS, Q3; SPNGFS, Q3/Q4; ECSGFS, Q4. Annual maturity data (Farrell et al., 2012; Hüssy et al., 2012b). Natural mortality from King (1995). Discards have been included in the assessment since 2003 from nondirected fisheries. 88 ICES Advice 2013, Book 9

93 Indicators Commercial catchatage data, acoustic survey ( ), distribution, abundance from WIBTSQ4 surveys, and IBTS survey timeseries. Working group report WGWIDE (ICES, 2013). ICES Advice 2013, Book 9 89

94 9.4.6 Supporting information October 2013 ECOREGION Widely distributed and migratory stocks STOCK Boarfish in the Northeast Atlantic Reference points MSY approach Precautionary reference points (Unchanged since 2013) Type Value Technical basis MSY B trigger Not defined. F MSY 0.23 r/2 from Schaefer surplus production model. Not defined. Outlook for 2014 Basis: Catch (2013) = tonnes (EU TAC = t and average discards = 6448 t); F 2013 = 0.145; TSB (2014) = tonnes. Rationale Catch (2014) Basis F (2014) TSB (2015) %TSB change 1) % TAC change 2) MSY approach F MSY Zero catch % TAC reduction Rollover TAC (same as intermediate year) % TAC increase Weights in thousand tonnes. 1) TSB 2015 relative to TSB 2014 at start of year. 2) Catch 2014 relative to TAC MSY approach Following the MSY approach implies a fishing mortality at F MSY = On this basis, ICES advises that catches in 2014 should not be more than t. If discard rates do not change from the average of the last 10 years 2003 to 2012 (6448 t) should be subtracted from this, resulting in landings in 2014 of no more than t. Additional considerations Management considerations In 2010 an interim management plan, proposed by Ireland, included a number of measures to mitigate potential bycatch of other TAC species in the boarfish fishery. A closed season from 15 March to 31 August was proposed, as anecdotal evidence suggested that mackerel and boarfish are caught in mixed aggregations during this period. This proposed closed season has been followed by participating vessels on a voluntary basis in 2011 and A closed season was also proposed in Division VIIg to prevent catches of Celtic Sea herring, known to form feeding aggregations in this region at these times. If catches of a single species other than boarfish totals more than 5% of the total catch in the boarfish fishery, by day and by ICES statistical rectangle, and this species is covered by a TAC, then boarfish fishery must cease in that rectangle. In 2012, a management plan was submitted by the Pelagic RAC. This plan has yet to be evaluated by ICES. Bottomtrawl survey data suggest a continuity of distribution spanning ICES Subareas IV, VI, VII, VIII, and IX (Figure ). Isolated small occurrences appear in the North Sea (ICES Subarea IV) in some years. A discontinuity in distribution was suggested between ICES Divisions VIIIc and IXa as boarfish were considered very rare in northern Portuguese waters but abundant further south (Cardador and Chaves, 2010); however, it is unclear if this suggested discontinuity represents a stock separation. Based on these data, a single stock is considered to exist in ICES Subareas 90 ICES Advice 2013, Book 9

95 IV, VI, VII, and VIII, and in Division IXa. This distribution is broader than the current EC TAC area (Subareas VI, VII, and VIII) and for the purposes of assessment in 2013 only data from these areas were utilized. A dedicated study on the stock structure of boarfish within the Northeast Atlantic and the Mediterranean Sea will commence in October 2013, the results of which will feed into future assessments. Regulations and their effects In 2010, the European Commission notified member states that mesh sizes less than 100 mm were illegal and that fisheries for boarfish should not be prosecuted with mesh sizes of less than 100 mm. However, in 2011, the European Parliament voted to change Regulation 850/1998 to allow fishing for boarfish using mesh sizes ranging from 32 to 54 mm. In 2011 EC introduced a precautionary TAC. In 2012 the TAC was based on ICES advice. Prior to 2011 the fishery was unregulated. Information from the fishing industry Due to developments in the pumping technology a number of Danish and Irish pelagic vessels have targeted boarfish in recent years, encountering large quantities of boarfish in ICES Divisions VIIj and VIIh. Both fleets consider that there is a very large stock of boarfish distributed over a large area. Other fishing vessels (demersal vessels and pelagic freezer trawlers) operating in the Celtic Sea are experiencing increases in their bycatches of boarfish, which they consider a nuisance as they can damage both the quality of the catch and their nets. Since the beginning of 2010, the Danish and Irish pelagic fleets have been actively involved in providing scientific samples of boarfish. They have also directly funded biological studies, target strength research, and dedicated boarfish acoustic surveys ( ). The pelagic RAC has developed the proposed fisheries management plan for boarfish. Data requirements Prior to 2010, commercial sampling effort was poor, with sampling conducted by only a small number of Irish and Danish vessels. Since 2010 sampling has been considered adequate, although boarfish is not currently included under the EU Data Collection Framework. A comprehensive and coordinated sampling scheme and a continuation of the targeted acoustic survey are needed to provide the scientific basis for advice on this species. Comparison with previous assessment and advice In 2013 the advice is based on the results of a Schaefer surplus production model and follows the MSY approach. In 2012, the advice was based on the 2012 acoustic biomass survey estimate and an F MSY proxy. In 2011, the advice was based on average catches in Sources Blanchard, F., and Vandermeirsch, F Warming and exponential abundance increase of the subtropical fish Capros aper in the Bay of Biscay ( ). Comptes Rendus Biologies, 328: Cardador, F., and Chaves, C Boarfish (Capros aper) distribution and abundance in Portuguese continental waters (ICES Div. IXa). Working Document presented at the WGWIDE, Copenhagen, Farrell, E. D., Hüssy, K., Coad, J. O., Clausen, L. W., and Clarke, M. W Oocyte development and maturity classification of boarfish (Capros aper) in the Northeast Atlantic. ICES Journal of Marine Science, 69: Hüssy, K., Coad, J. O., Farrell, E. D., Clausen, L. W., and Clarke, M. W. 2012a. Age verification of boarfish (Capros aper) in the Northeast Atlantic. ICES Journal of Marine Science, 69: Hüssy, K., Coad, J. O., Farrell, E. D., Clausen, L. W., and Clarke, M. W. 2012b. Sexual dimorphism in size, age, maturation and growth characteristics of boarfish (Capros aper) in the Northeast Atlantic. ICES Journal of Marine Science, 69: ICES Report on the Classification of Stock Assessment Methods developed by SISAM. ICES CM 2012/ACOM/SCICOM: pp. ICES Report of the Working Group on Widely Distributed Stocks (WGWIDE), 27 August 02 September 2013, ICES Headquarters, Copenhagen. ICES CM 2013/ACOM:15. King, M., Fisheries Biology, Assessment and Management. Fishing News Book. 34P. Minto, C., Clarke, M. W., and Farrell, E. D Investigation of the yield and biomassperrecruit of the boarfish Capros aper. Working Document, WGWIDE ICES Advice 2013, Book 9 91

96 Figure Boarfish in the Northeast Atlantic. Irish catches by rectangle (being representative of the area where all countries are fishing). 92 ICES Advice 2013, Book 9

97 Figure Boarfish distribution in the Northeast Atlantic. Presence and absence in the IBTS and WIBTS surveys. ICES Advice 2013, Book 9 93

98 Figure Boarfish in the Northeast Atlantic. Catch in tonnes (upper left panel). Survey indices from the boarfish acoustic survey, five individual international bottomtrawl surveys (IBTS), and the English Celtic Sea Groundfish Survey (dots), with modelled catch per unit effort estimates from surplus production assessment (black line) and 95% confidence intervals (dashed lines). Total biomass in tonnes. Harvest ratio is total catch divided by total biomass. 94 ICES Advice 2013, Book 9

99 Table Boarfish in the Northeast Atlantic. ICES advice, management, and landings. Year ICES Advice Predicted catch corresp. to TAC 1 Bycatch quota 2 ICES Catch advice 2001 None None None None None None None None None None None None None None None None None None None None None None None None None None None None None None None No increase in catches MSY approach MSY approach Weights in thousand tonnes. 1 EU and international waters of Subareas VI, VII, and VIII. 2 The maximum permitted bycatch (5%) of boarfish allowed to be subtracted from the EC quotas for western and for North Sea horse mackerel. The 5% applies to boarfish, whiting, haddock, and/or mackerel. Table discards (tonnes). Boarfish in the Northeast Atlantic. Working Group estimates of landings by country and total Year Ireland Denmark Scotland Total Estimated Total catch including landings discards discards NA NA ICES Advice 2013, Book 9 95

100 Table Low and High in the table below indicate the 95% credible intervals (Bayesian analogue of confidence intervals) spanning % of the density. TSB (t) Yield (t) F Low Mean High Catch Landings Discards Low Mean High ICES Advice 2013, Book 9

101 Annex 1 Proposed management plan A management plan has been proposed by the Pelagic RAC. This management plan has not yet been evaluated by ICES. The plan is presented below. 1 ) The TAC setting rules shall apply. Precedence is in decreasing order from Rule 1.1. These are shown in the table below. The decision year for TAC setting is the last year in the assessment, and not the TAC year. Rule Assessment Uncertainty Condition Procedure 1.1.a SSB and F Low SSB > B trigger F target 1.1.b SSB < B trigger SSB ( F target / B trigger ) 1.2.a SSB and F Higher SSB > B trigger F target 1.2.b SSB < B trigger SSB ( F target / B trigger ) G 1.3.a F Any F < F target Reference TAC * G 1.3.b F > F target, RTAC + ( RTAC / F lim F pa) (F F pa) G 1.4.a U Any U > U pa, TAC = Reference TAC G 1.4.b U < U pa, TAC = U ( Reference TAC / U pa ) G 1.5. Survey biomass Any TAC y,q3,4 = TACy+1, q1 = ASB 1 exp F _ G ASB 1 exp F _ G None No information on stock status and no risk of recruitment impairment TAC = t (interim management plan TAC) 2 ) Notwithstanding Paragraph 1, if in the opinion of ICES, the stock is at risk of recruitment impairment, a TAC shall be based on advice given by ICES, and at a lower level than provided for in Paragraph 1, rules 1.1 to ) Closed seasons, closed areas, and moving on procedures shall apply to all directed boarfish fisheries as follows: i ii iii A closed season shall operate from 15th March to the 31st August. This is because it is known that herring and mackerel are present in these areas and may be caught with boarfish. A closed area shall be implemented inside the Irish 12 mile limit south of 52 30'N from 12th February to 31st October, in order to prevent catches of Celtic Sea herring, known to form aggregations at these times. If catches of other species covered by TAC amount to more than 5% of the total catch by day by ICES statistical rectangle, then all fishing must cease in that rectangle for five consecutive days. ICES Advice 2013, Book 9 97

102 9.4.7 Advice November 2013 ECOREGION STOCK Widely distributed and migratory stocks European eel Advice for 2014 The status of eel remains critical and urgent action is needed. ICES advises that all anthropogenic mortality (e.g. recreational and commercial fishing, hydropower, pollution) affecting production and escapement of silver eels should be reduced to as close to zero as possible, until there is clear evidence of sustained increase in both recruitment and the adult stock. Restocking under the eel management plans is not expected to have contributed to increased silver eel escapement yet because of the generational lag time. The efficacy of restocking for recovering the stock remains uncertain while evidence of net benefit is lacking. Stock status The annual recruitment of glass eel to European waters has increased over the last two years, from less than 1% to 1.5% of the reference level in the North Sea series, and from 5% to 10% in the Elsewhere series. Management plans A management framework for eel within the EU was established in 2007 through an EC Regulation (EC No. 1100/2007; EC, 2007), but there is no internationally coordinated management plan for the whole stock area. The objective of the EU regulation is the protection, recovery, and sustainable use of the stock. To achieve the objective, Member States have developed eel management plans for their river basin districts, designed to permit with high probability the escapement to the sea of at least 40% of the silver eel biomass relative to the best estimate of escapement that would have existed if no anthropogenic influences had impacted the stock. ICES has evaluated the conformity of the national management plans with EC Regulation No. 1100/2007 (ICES, 2009a, 2010a) and progress in implementing the Environmental Management Plan (EMP) actions (ICES, 2013a). In 2007, eel was included in CITES Appendix II that deals with species not necessarily threatened with extinction, but for which trade must be controlled to avoid utilization incompatible with the survival of the species (see Eel was listed in September 2008 as critically endangered in the IUCN Red List. The CITES listing was implemented in March Biology European eel life history is complex. The stock is panmictic and indications point at random mating of adults in the spawning area in the southwestern part of the Sargasso Sea. The newlyhatched leptocephalus larvae drift with the ocean currents to the continental waters of Europe and North Africa where they metamorphose into glass eels; this dispersal is believed to be random. The growth stage, known as yellow eel, takes place in marine, brackish, or freshwater. This stage may last from as little as two years to several decades prior to metamorphosis to the silver eel stage and maturation. Ageatmaturity varies according to latitude, ecosystem characteristics, and densitydependent processes. The European eel life cycle is shorter for populations in the southern part of their range compared to the north. Silver eels then migrate to the Sargasso Sea where they are believed to spawn and die. Environmental influence on the stock Environmental conditions at the spawning grounds and during the oceanic phase are likely to affect the stock, but it is unknown whether and to what extent changes in these conditions have influenced the observed stock declines. Environmental impacts in transitional and fresh waters, which include habitat alteration, barriers to eel passage, deterioration in water quality, and presence of nonnative diseases and parasites, contribute to the anthropogenic stresses and mortality on eels and also affect their reproductive success. It is anticipated that the implementation of the Water Framework and Marine Strategy Framework Directives may result in improvements to the continental environment and that this may have a positive effect on the reproductive potential of silver eel. 98 ICES Advice 2013, Book 9

103 An increased awareness of contaminants in eel, in relation to safe human consumption limits, is leading to fishery closures to protect consumers. These selective closures may lead to an increased proportion of low quality spawners in the escapement. It is likely that there is a negative relationship between contaminant loads, parasites, and diseases in eels and their spawning success. However, these effects have not been quantified. The fisheries and other mortality causes The assessment and management of the fisheries and nonfisheries mortality factors are managed by national and regional authorities. Fisheries take place on all available continental life stages throughout the distribution area, although fishing pressure varies from area to area, from almost nil to heavy overexploitation. The nonfishing anthropogenic mortality factors can be grouped as those due to (a) hydropower, pumping stations, and other water intakes; (b) habitat loss or degradation; and (c) pollution, diseases, and parasites. In addition, anthropogenic actions may affect mortality due to predators, e.g. conservation or culling of predators. In the 2012 EMP Progress Reports, 43 EMPs reported mortality rates for both fishing and nonfishing pressures: the rate due to fishing (F) exceeded that due to nonfishing pressures (H) in 24 eel management units (EMUs), H exceeded F in 15 EMUs, and the rates of F and H were equal in the last four EMUs. Effects of the fisheries on the ecosystem The current fishery probably has little direct influence on aquatic ecosystems, with the possible exception of local bycatch issues. However, the eel is an important and frequently dominating species in the ecosystem, and its substantial reduction, whether due to fisheries or other causes may have had a more profound effect. There is limited knowledge on the magnitude of these effects. Data quality considerations Total landings and effort data are incomplete. There is a great heterogeneity among the timeseries of landings because of inconsistencies in reporting by, and between, countries and incomplete reporting. Changes in management practices have also affected the reporting of noncommercial and recreational fisheries. Many EU Member States have not completely reported stock indicators (22 of 81 EMPs did not report all biomass indicators and 38 did not report all mortality indicators in 2012), and there are inconsistencies in the approaches used to calculate reported stock indicators. The distribution area of the eel extends considerably beyond the EU, and data from countries in these other regions were not available. A complete reporting of indicators covering the range of the European eel is required for a full assessment of the stock. To facilitate this, data collection and analysis should be internationally standardized. Scientific basis The assessment is based on data from fisheries and scientific surveys, and on national stock indicators. Monitoring trends in recruitment has been the main tool in the recent past for assessing the overall status of the eel stock. Methods based on national stock indicators of biomass and mortality, have been recently developed and have been applied this year. Assessment type Input data Discards and bycatch Indicators Other information Working group report Trend analysis; comparison of indicators with management reference points. Glass eel and yellow eel recruitment indices; national stock indicators of biomass and mortality. Not included. See above. Landing statistics incomplete and reporting inconsistent. Stock indicators incomplete from eel management units/countries in the EU. Stock indicators and other data missing from noneu states. There is no international legislative requirement to collect and provide data for the whole stock area. Joint EIFAAC/ICES WGEEL (ICES, 2013b). ICES Advice 2013, Book 9 99

104 9.4.7 Supporting information November 2013 ECOREGION STOCK Widely distributed and migratory stocks European eel Reference points The EC Regulation sets an escapement target of at least 40% of the silver eel biomass relative to the best estimate of escapement that would have existed if no anthropogenic influences had impacted the stock. Additional considerations Management considerations There is evidence that translocated and stocked eel can contribute to yellow and silver eel production in recipient waters, but evidence of contribution to actual spawning is limited by the general lack of knowledge of the spawning of any eel. Internationally coordinated research is required to judge the net benefit of restocking for the overall population, including carrying capacity estimates of glass eel source estuaries as well as detailed mortality estimates at each step of the stocking process. When stocking to increase silver eel escapement to aid stock recovery, an estimation of the prospective net benefit should be made prior to any stocking activity. Current high prices for glass eel are limiting the ability of EU Member States to meet stocking targets in the eel management plans. Where eel are translocated and stocked, a means must be put in place to evaluate their fate and their contribution to silver eel escapement. This might take the form of batch marking of eel to distinguish groups recovered in later surveys (e.g. recent Swedish and French marking programmes), or implementation of tracking studies of eel of known origin. Factors affecting the fisheries and the stock Regulations and their effects As eel is a longlived species and anthropogenic mortalities occur over all of its continental lifespan, the effect of management measures on the eel stock is expected to take several years, up to a decade or more, to be detected (ICES, 2009b). While measures directly increasing the escapement of silver eels (e.g. fisheries closures, trapandtransport) may result in an increase in glass eel recruitment within two to three years, it will take longer to see the effects of measures affecting glass and yellow eel mortalities. Furthermore, it will take a decade or more for any increases in recruitment to affect subsequent spawner escapement, and when this occurs, the natural variability of these migrations, local site effects, and sampling error will further delay the detection of such changes (ICES, 2011a, 2011b, 2011c). The reporting by Member States to the EC in 2012 is a first step in reviewing progress with the stock recovery, and the present assessment indicates that, in the short term, a major further reduction in anthropogenic mortality is required. The implementation of the eel management plans have resulted in restrictions on fisheries. Poaching is believed to be widespread in some countries. The environment Uncertainties remain in the local and international effects of environmental impacts on the stock. It is not yet possible to integrate eel quality in the quantitative stock assessment. In some areas contamination by hazardous substances is so high that an effect on reproduction may occur, but hard scientific evidence (dose/response studies) is not available. Gaps in knowledge mean that there is a need to better quantify the effects of parasites, diseases, and contaminants on migration and reproduction success. Furthermore, there is a need for standardization of eel quality assessments as different analytical methods and data reporting make comparisons difficult. The nonnative parasite Anguillicola crassus that infects the swimbladder of eel is now widespread in Europe and is continuing to spread. As A. crassus impacts on the health, energy reserves, and migratory behaviour of the eel, it could hinder recovery of the stock. 100 ICES Advice 2013, Book 9

105 Scientific basis Data and methods The assessment methods used for the 2013 assessment are based on analysis of eel recruitment timeseries. Monitoring recruitment is not an obligation in the Water Framework Directive, Data Collection Framework, or Eel Regulation. It is anticipated that eel recruitment monitoring will be included in the Data Collection MultiAnnual Plans (DC MAP) from 2015 onwards, as recommended by ICES in 2012 (ICES, 2012). Some EU Member States now report quantitative estimates of the stock indicators (EMP progress reports 2012, ICES Data Call 2013, Country reports to WGEEL 2013). However, the reporting is incomplete from within the EU, and there is no legislative requirement for the collection and reporting of data from outside the EU. Both limitations need to be addressed. Standardization Regional or international coordination and standardization will facilitate data collection, and allow the international integration towards stockwide assessment and advice. Uncertainties in assessment and forecast The assessments are limited by the incomplete spatial and temporal coverage of the available data. Quantifying the impact of reduced eel quality on the reproductive potential of spawners should be pursued. Considerations regarding the quality of the advice Advice derived from the available recruitment data is robust to the uncertainties in these data. Comparison with previous assessment and advice The assessment is based on examination of recruitment trends as before. The recruitment has recently increased, to 1.5% of the reference level in the North Sea series, and to 10% in the Elsewhere series. This might affect escapement biomass in several years. Therefore, there is no change in the perception of the status of the stock. Sources of information EC European Commission. Commission Regulation (EC) No. 1881/2006 of 19 December 2006 setting maximum levels for certain contaminants in foodstuffs. Official Journal of the European Union, 2006: EC COUNCIL REGULATION (EC) No. 1100/2007 of 18 September 2007 establishing measures for the recovery of the stock of European eel. Official Journal of the European Union, L 248/17. ICES European eel. In Report of the ICES Advisory Committee on Fishery Management (ACFM), ICES Cooperative Research Report, 255: ICES. 2009a. Report of the ICES Advisory Committee, ICES Advice 2009, Book 11: Technical Services. 71 pp. ICES. 2009b. Report of the EIFAAC/ICES Working Group on Eels (WGEEL), 7 12 September 2009, Göteborg, Sweden. ICES CM 2009/ACOM: pp. ICES. 2010a. Report of the ICES Advisory Committee, ICES Advice 2010, Book 11: Technical Services. 155 pp. ICES. 2010b. Report of the Joint EIFAAC/ICES Working Group on Eels (WGEEL), September ICES CM 2010/ACOM: pp. ICES. 2010c. Country reports. In Report of the Joint EIFAAC/ICES Working Group on Eels (WGEEL), September ICES CM 2010/ACOM:18, Annex pp. Available as a separate document at ports_2010.pdf. ICES. 2010c. Report of the Study Group on International PostEvaluation on Eels (SGIPEE), May 2010, Vincennes, France. ICES CM 2010/SSGEF: pp. ICES. 2011a. Report of the Study Group on International PostEvaluation on Eels (SGIPEE), May 2011, London, UK. ICES CM 2011/SGEF: pp. ICES. 2011b. Report of the Joint EIFAAC/ICES Working Group on Eels (WGEEL), September ICES CM 2011/ACOM: pp. ICES. 2011c. Country reports. In Report of the Joint EIFAAC/ICES Working Group on Eels (WGEEL), September ICES CM 2011/ACOM:18, Annex pp. Available as a separate document at ICES Advice 2013, Book 9 101

106 portswgeel_2011.pdf. ICES Report on the Workshop on Eel and Salmon DCF Data (WKESDCF). 3 6 July, 2012, Copenhagen, Denmark. ICES CM 2012/ACOM: pp. ICES. 2013a. ICES Advice in response to EU request to ICES to technically evaluate the Eel Management Plan progress. In Report of the ICES Advisory Committee, ICES Advice 2013, Book 9, Section pp. ICES. 2014b. Report of the Joint EIFAAC/ICES Working Group on Eels (WGEEL), March 2013 in Sukarietta, Spain, and 4 10 September 2013 in Copenhagen, Denmark. ICES CM 2013/ACOM: pp. 102 ICES Advice 2013, Book 9

107 Figure WGEEL recruitment index: mean of estimated (GLM) glass eel recruitment for the North Sea and elsewhere in Europe updated to The GLM (recruit = area:year + site) was fitted on 34 series glass eel series comprising either pure glass eel or a mixture of glass eels and youngofyear yellow eels and scaled to the average. No series for glass eel are available in the Baltic area. Note the logarithmic scale on the yaxis. The North Sea series are from Norway, Sweden, Germany, Denmark, Netherlands, and Belgium. The Elsewhere series are from UK, Ireland, France, Spain, Portugal, and Italy. ICES Advice 2013, Book 9 103

108 Figure Mean of estimated (GLM) yellow eel recruitment and smoothed trends for Europe updated to The GLM (recruit = year + site) was fitted to ten yellow eel series and scaled to the average. Note the logarithmic scale on the yaxis. The grey band shows the 95% pointwise confidence interval of the smoothed trend. These time series are from Sweden, Denmark, and Belgium. 104 ICES Advice 2013, Book 9

109 9.4.8 Advice June 2013 ECOREGION STOCK Widely distributed and migratory stocks Greater forkbeard (Phycis blennoides) in the Northeast Atlantic Advice for 2014 The advice given in 2012 for greater forkbeard (Phycis blennoides) assessment units is biennial and valid for 2013 and 2014 (see ICES, 2012). The advice is summarized in the table below. Sources ICES Greater forkbeard (Phycis blennoides) in the Northeast Atlantic. Report of the ICES Advisory Committee, ICES Advice, Book 9: Table Greater forkbeard in the Northeast Atlantic. ICES advice, management, and landings. Year ICES Advice 2003 Fisheries accompanied by programmes to collect data, and expand very slowly unless proven to be sustainable Predicted catch corresp. to advice TAC 1) EC Subareas I, II, III, and IV TAC 1) EC Subareas V, VI, and VII TAC 1) EC Subareas VIII and IX TAC 1) EC Subareas X and XII Sum of TACs ICES landings Northeast Atlantic Biennial Fisheries accompanied by 3.0 programmes to collect data 2006 Biennial Fishery should not be allowed to expand, unless proven to be sustainable Biennial Fishery should not be allowed to expand, unless proven to be sustainable Biennial Fishery should not be allowed to expand, and a reduction in catches should be considered No new advice, same as % reduction in catches No new advice, same as 2013 Weights in thousand tonnes. 1) For Phycis spp. ICES Advice 2013, Book 9 105

110 9.4.9 Advice June 2013 ECOREGION STOCK Widely distributed and migratory stocks Greater silver smelt (Argentina silus) in the Northeast Atlantic Advice for 2014 The advice given in 2012 for greater silver smelt (Argentina silus) assessment units is biennial and valid for 2013 and 2014 (see ICES, 2012). The advice is summarized in the table below. Sources ICES Greater silver smelt (Argentina silus) in the Northeast Atlantic. Report of the ICES Advisory Committee, ICES Advice, Book 9: Table Greater silver smelt (Argentina silus) in the Northeast Atlantic. Summary of advice for different assessment units and landings. Year ICES advice in Division Va ICES advice in other areas 2 ICES landings in all areas No fishery unless data collection on (by)catch, no 21.8 expansion unless proven to be sustainable Biennial No fishery unless accompanied by programmes 33.7 to collect data on both target and bycatch fish Biennial The fishery should not be The fishery should not be allowed to expand 39.1 allowed to expand unless it can be shown that it is sustainable unless it can be shown that it is sustainable 2008 Biennial Biennial Same advice as 2007 Same advice as Biennial Biennial Reduce exploitation rates to 2001 The fishery should not be allowed to expand, and levels a reduction in catches should be considered 2012 No new advice, same as 2011 No new advice, same as Fproxy ( ) ( < 3700 t) Reduce catches by 10% (31300t) 2014 No new advice, same as 2013 No new advice, same as 2013 Weights in thousand tonnes. 1 Advice for Division Va has been presented separately since Subareas I, II, IV, VI, VII, VIII, IX, X, XII, and XIV, and Divisions IIIa and Vb. Prior to 2007 Division Va was included. 106 ICES Advice 2013, Book 9

111 Advice June 2013 ECOREGION STOCK Widely distributed and migratory stocks Hake in Division IIIa, Subareas IV, VI, and VII, and Divisions VIIIa,b,d (Northern stock) Advice for 2014 ICES advises on the basis of the MSY approach that landings should be no more than t in Even though some discards are included in the assessment, the total amount of discards cannot be quantified. Therefore total catches cannot be calculated. Stock status MSY (FMSY) Precautionary approach (Fpa,Flim) MSY (Btrigger) Precautionary approach (Bpa,Blim) Qualitative evaluation F (Fishing Mortality) Appropriate Undefined SSB (SpawningStock Biomass) Undefined Undefined Above poss. reference points SSB in 1000 t Fishing Mortality (ages 1580 cm) 100 Landings 800 Recruitment (age 0) Landings in 1000 t Recruitment in millions Figure Hake in Division IIIa, Subareas IV, VI, and VII, and Divisions VIIIa,b,d. Summary of stock assessment (weights in thousand tonnes). Assumed values are shaded. Top right: SSB/F for the timeseries used in the assessment. The spawning biomass has been increasing since 1998 and is estimated to be record high in Fishing mortality has decreased sharply in recent years and was equal to the F MSY proxy in 2011 and Recruitment fluctuations appear to be without substantial trend over the whole series. After low recruitments in 2009, 2010, and 2011, the last recruitment (2012) is estimated to be the highest in the timeseries. Management plans A recovery plan was agreed by the EU in 2004 (EC Reg. No. 811/2004, Annex ). The aim of the plan is to increase the SSB to above t with a fishing mortality (F MP) of 0.25, constrained by a yeartoyear change in TAC of 15% when SSB is above t. This plan has not been evaluated by ICES. ICES Advice 2013, Book 9 107

112 Biology European hake is widely distributed over the Northeast Atlantic shelf. Although there is no clear evidence of multiple populations in the Northeast Atlantic, ICES assumes two different stock units. The northern stock is distributed over a wide area. There are two major nursery areas: in the Bay of Biscay and off southern Ireland. The fisheries Hake is caught in mixed fisheries together with megrim, anglerfish, and Nephrops. Discards of juvenile hake can be substantial in some areas and fleets. An important increase in landings has occurred in the northern part of the distribution area (Division IIIa, and Subareas IV and VI) in recent years. Several changes in fishing technology have occured in the fishery in recent years : increased mesh sizes in several gears, introduction of the high vertical opening trawls in the mid1990s, and introduction of selective gears in the Nephrops trawl fishery of the Bay of Biscay (square mesh panel). Catch distribution Total landings (2012) = 75.2 kt (20% trawl, 21% gillnet, 18% longline, and 41% unspecified gears). Discards of 14.6 kt (16% of catches). Discard data are only available for some of the fleets and not all data are included in the assessment. Effects of the fisheries on the ecosystem Because hake is a top predator, its abundance has implications on the survival of conspecifics (cannibalism) and other species, e. g. blue whiting, horse mackerel, and sardine. Quality considerations The assessment suffers from some shortage of tuning data, particularly in relation to earlier years, for areas outside of Subareas VII and VIII and for the larger individuals in the population. Discards have increased sharply in the last year in northern areas (Subareas IV and VI), but they are not included in the assessment. Some discards from Subareas VII and VIII are included in the assessment. Model growth estimates are uncertain, but they are in accordance with the tagging information. SSB ('000 tonnes) Fishing mortality: 26 Recruitment. Age: Millions Figure Hake in Division IIIa, Subareas IV, VI, and VII, and Divisions VIIIa,b,d. Historical assessment results (finalyear recruitment estimates are included). F is based on lengths cm, corresponding to approximately 1 5 years old; in previous assessment years the F age range was 2 6 years old. Scientific basis Assessment type Lengthbased model (SS3). Stock data category Category 1. Input data Commercial landings; Four survey indices (EVHOEWIBTSQ4, SpPGFSWIBTSQ4, IGFSWIBTSQ4, and RESSGASC); Maturity data: constant maturity used (Martin, 1991); Natural mortality: constant value (0.4) used. Discards and bycatch Partial discard estimates have been included in the assessment since Indicators None. Other information This stock will be benchmarked in Working group report WGHMM (ICES, 2013). 108 ICES Advice 2013, Book 9

113 Supporting information June 2013 ECOREGION STOCK Widely distributed and migratory stocks Hake in Division IIIa, Subareas IV, VI, and VII, and Divisions VIIIa,b,d (Northern stock) Reference points Type Value Technical basis MSY MSY B trigger Not defined. Approach F MSY 0.24 F 30%SPR (Section in ICES, 2010). B lim Not defined. Precautionary B pa Not defined. Approach F lim Not defined. F pa Not defined. (unchanged since: 2010) Outlook for 2014 Basis: F (2013) = Mean F = 0.24; SSB (2014) = ; R (2013) = 315 million (GM ); landings (2013) = ; discards (2013) = Rationale Human consump. landings (2014) Basis F Total (2014) F HC (2014) F Disc (2014) Disc. (2014) Catch Total (2014) SSB (2015) %SSB change 1) %TAC change 2) MSY F MSY approach (F sq 0.99) % +49% Recovery % TAC % 15% plan (F sq 0.745) Zero catch 0.0 F = % 100% Other options F sq % 83% F sq % 51% % TAC (F sq 0.535) % 15% F sq % 21% Equal TAC (F sq 0.64) % +0% % TAC % 15% (F sq 0.745) F sq % +10% F sq % +36% F sq % +50% F sq % +76% Weights in thousand tonnes. 1) SSB 2015 relative to SSB ) Human consumption landings 2014 relative to TAC MSY approach Because MSY B trigger has not been identified for this stock, the ICES MSY approach has been applied without considering SSB in relation to MSY B trigger. Following the ICES MSY approach implies fishing mortality at F MSY = 0.24, resulting in catches of no more than t in This is expected to lead to an SSB of 333 kt in If discard rates do not change, this implies landings of no more than t in Not all discards are accounted for in the model and in the forecast, and therefore cannot be quantified even though they are substantial (in 2012 other observed, but also partial, discards accounted for 10% by weight of the total catch). ICES Advice 2013, Book 9 109

114 Management plan(s) The current recovery plan (EC Reg. No. 811/2004) uses target values based on precautionary reference points that are no longer appropriate. Additional considerations Discards of juvenile hake can be substantial in some areas and fleets. The spawningstock biomass and the longterm yield can be substantially improved by reducing mortality of small fish. This could be achieved by measures that reduce unwanted bycatch through shifting the selection pattern towards larger fish. TACs have been ineffective in regulating the fishery in recent years as landings greatly exceeded the TACs. Hake in the ICES area is managed and assessed as two separate stocks. There is no biological basis for the current ICES stock definition of northern and southern hake. These stocks have similar biology with an unknown degree of mixing. Data and methods The assessment is carried out with partial discards included. There is large uncertainty associated with estimation of discards. In order to reduce uncertainty in discards estimates, an increased sampling level for onboard observer programmes is needed for some fleets (nonnephrops trawlers, gillnetters, and longliners). Hake otoliths are currently collected but not used in the assessment due to lack of a validated ageing method. It is therefore important that research on hake ageing from otoliths be continued. Management considerations The fast growth rate and the assumed high natural mortality generates a rapid turnover of the hake stock dynamics. This means that shortterm projections of SSB and landings are more sensitive to variations in recruitment. The current SSB is above any potential candidate value for MSY B trigger. Uncertainties in assessment and forecast There is some concern that the steep estimated increase in SSB and decrease in F may not be totally accurate, although all signals coming from the surveys and the fishery are consistent in showing a strong increase in stock biomass. The strong 2008 year class can be seen clearly in the landings. There will be a benchmark in 2014, where issues with the assessment will be considered. The shortterm forecast of SSB and yield obtained by this year s assessment are influenced by the high recruitment estimated in 2012, which is based on consistent observations from two surveys. Only partial discards are included in the assessment and forecast. The overall dynamics of the stock are sensitive to the growth parameters estimated in the model. Comparison with previous assessment There was no assessment in Compared to the 2011 assessment, the current assessment estimates of SSB in 2011 have been revised upwards by 70% and the F in 2010 revised downwards by 36% because of upward revisions of incoming recruits. The advice is based on the MSY approach. Sources ICES Report of the ICES Advisory Committee, ICES Advice 2010, Book pp. ICES Report of the Working Group on the Assessment of Southern Shelf Stocks of Hake, Monk, and Megrim (WGHMM), 5 11 May 2011, ICES Headquarters, Copenhagen. ICES CM 2011/ACOM:11. ICES Report of the Working Group on the Assessment of Southern Shelf Stocks of Hake, Monk, and Megrim (WGHMM), May 2013, ICES Headquarters, Copenhagen. ICES CM 2013/ACOM:11A. Martín, I A preliminary analysis of some biological aspects of hake (Merluccius merluccius) L.1758) in the Bay of Biscay. ICES CM 1991/G : ICES Advice 2013, Book 9

115 Figure Hake in Division IIIa, Subareas IV, VI, and VII, and Divisions VIIIa,b,d. Equilibrium projections of longterm yieldperrecruit (upper panel) and SSBperrecruit (lower panel) at different fishing mortality rates. Recruitment (age 0) in millions Stock Recruitment SSB in 1000 t Figure Hake in Division IIIa, Subareas IV, VI, and VII, and Divisions VIIIa,b,d. Stock recruitment plot. ICES Advice 2013, Book 9 111

116 Table Hake in Division IIIa, Subareas IV, VI, and VII, and Divisions VIIIa,b,d. ICES advice, management, landings, discards, and catches. Year ICES Predicted landings Advice corresp. to advice 1987 Precautionary TAC; juvenile protection Precautionary TAC; juvenile protection Precautionary TAC; juvenile protection Precautionary TAC; juvenile protection Precautionary TAC; juvenile protection If required, precautionary TAC Enforce juvenile protection legislation Agreed ICES Discards 2 ICES TAC 1 landings catch 1994 F significantly reduced < * % reduction in F % reduction in F % reduction in F % reduction in F Reduce F below F pa < * % reduction in F < * 2001 Lowest possible catch, recovery plan Lowest possible catch / recovery plan Lowest possible catch / recovery plan * % reduction in F or recovery plan* < * 2005 F= F= * 2007 Recovery plan limits Recovery plan limits F =0.25 = F pa F =0.25 = F pa See scenarios MSY transition MSY transition ICES Advice 2013, Book 9

117 2014 MSY approach Weights in thousand tonnes. 1 Sum of area TACs, corresponding to northern stock plus Division IIa (EC zone only) new discard estimates. In years marked with *, partial discard estimates are available and used in the assessment. For remaining years for which no values are presented, some estimates are available but not considered valid and thus not used in the assessment. ICES Advice 2013, Book 9 113

118 Table Hake in Division IIIa, Subareas IV, VI, and VII, and Divisions VIIIa,b,d. Estimated landings, discards, and catches (in thousand tonnes), by ICES area. Landings (1) Discards (2) Catches (3) Year IVa+VI VII VIIIa,b Unallocated Total Total Total * * * * * * (1) Spanish data for not revised, data for Subarea VIII for include data for Divisions VIIIa,b only. Data for are revised based on French surveillance data. Divisions IIIa and IVb,c are included in column "IIIa, IV and VI" only after There are some unallocated landings ( moreover for the period ). (2) Discard estimates from observer programmes. In years marked with *, partial discard estimates are available and used in the assessment. For remaining years for which no values are presented, some estimates are available but not considered valid and thus not used in the assessment In the years with data, only discards from Spanish trawlers and French Nephrops trawlers are included. (3) From 1978 total catches used for the Working Group. 114 ICES Advice 2013, Book 9

119 Table Hake in Division IIIa, Subareas IV, VI, and VII, and Divisions VIIIa,b,d. Summary of stock assessment. Year Recruit Total Total Landings Discards (1) Catch Yield/SSB F (15 80 cm) Age 0 Biomass SSB * Arith.Mean Units Thousands Tonnes Tonnes Tonnes Tonnes Tonnes (1) Discards used in the assessment. In years with () discards are not available or considered unreliable. * GM ( ). ICES Advice 2013, Book 9 115

120 Annex Extract from recovery plan for Northern hake: Council Regulation (EC) No. 811/2004 Article 1 Subjectmatter This Regulation establishes a recovery plan for the Northern hake stock which inhabits the ICES Division IIIa, ICES Subarea IV, ICES Divisions V(b) (Community waters ), VIa (Community waters), ICES Subarea VII and ICES Divisions VIIIa,b,d,e ("the Northern hake stock"). Article 2 Purpose of the recovery plan The recovery plan referred to in Article 1 shall aim to increase the quantities of mature fish of the Northern hake stock concerned to values equal to or greater than tonnes. Article 3 Reaching of target levels Where the Commission finds, on the basis of advice from ICES and following agreement on that advice by the Scientific Technical and Economic Committee for Fisheries (STECF), that for two consecutive years the target level for the Northern hake stock concerned has been reached, the Council shall decide by qualified majority on a proposal from the Commission to replace the recovery plan by a management plan for the stock in accordance with Article 6 of Regulation (EC) No 2371/2002. Article 4 Setting of TACs A TAC shall be set in accordance with Article 5 where, for the Northern hake stock concerned the quantities of mature Northern hake have been estimated by the STECF, in the light of the most recent report of ICES, to be equal to or above tonnes. Article 5 Procedure of setting TACs 1. Each year, the Council shall decide by qualified majority on a proposal from the Commission on a TAC for the following year for the Northern hake stock concerned. 2. For 2004, the TAC shall be set at a level corresponding to a fishing mortality of 0,25, 4% less than status quo fishing mortality. For the subsequent years of the recovery plan, the TAC shall not exceed a level of catches which scientific evaluations carried out by the STECF, in the light of the most recent reports of ICES, indicate will correspond to a fishing mortality rate of 0, The Council shall not adopt a TAC whose capture is predicted by the STECF, in the light of the most recent report of the ICES, to lead to a decrease in spawning stock biomass in its year of application. 4. Where it is expected that the setting of the TAC for a given year in accordance with paragraph 2 will result in a quantity of mature fish at the end of that year in excess of the target level indicated in Article 2, the Commission will carry out a review of the recovery plan and propose any adjustments necessary on the basis of the latest scientific evaluations. Such a review shall in any event be carried out not later than 3 years following the adoption of this Regulation with the aim of ensuring that the objectives of the recovery plan are achieved. 5. Except for the first year of application of this Regulation, the following rules shall apply: (a) where the rules provided for in paragraphs 2 or 4 would lead to a TAC for a given year which exceeds the TAC of the preceding year by more than 15%, the Council shall adopt a TAC which shall not be more than 15% greater than the TAC of that year or;. (b) where the rule provided for in paragraphs 2 or 4 would lead to a TAC for a given year which is more than 15% less than the TAC of the preceding year, the Council shall adopt a TAC which is not more than 15% less than the TAC of that year. Article 6 Setting of TACs in exceptional circumstances Where the quantities of mature fish of the Northern hake stock concerned have been estimated by the STECF, in the light of the most recent report of the ICES, to be less than tonnes, the following rules shall apply: (a) Article 5 shall apply where its application is expected to result in an increase in the quantities of mature fish of the Northern hake stock concerned, at the end of the year of application of the TAC to a quantity equal to or greater than tonnes; (b) where the application of Article 5 is not expected to result in an increase in the quantities of mature fish of the Northern hake stock concerned, at the end of the year of application of the TAC, to a quantity equal to or greater than tonnes, the Council shall decide by a qualified majority, on a proposal from the Commission, on a TAC for the following year that is lower than the TAC resulting from the application of the method described on Article ICES Advice 2013, Book 9

121 Advice October 2013 ECOREGION STOCK Widely distributed and migratory stocks Herring in Subareas I, II, and V, and in Divisions IVa and XIVa (Norwegian springspawning herring) Advice for 2014 ICES advises on the basis of the management plan of EU, Faroe Islands, Iceland, Norway, and Russia that landings in 2014 should be no more than t. Minor discards are known to take place, but cannot be quantified accurately; the proportion of discards in the total catches are considered negligible. Stock status MSY (FMSY) Precautionary approach (Fpa) Management plan (FMP) MSY (Btrigger) Precautionary approach (Bpa,Blim) Management plan (SSBMP) F (Fishing Mortality) Appropriate Harvested sustainably Above limit SSB (SpawningStock Biomass) At trigger Full reproductive capacity At trigger Figure Herring in Subareas I, II, and V, and in Divisions IVa and XIVa (Norwegian springspawning herring). Summary of stock assessment. Top right: SSB and F over the years. The stock is declining and estimated at B pa in In the last 15 years, five large year classes have been produced (1998, 1999, 2002, 2003, and 2004). However, the available information indicates that year classes born after 2004 have been small. Fishing mortality in 2011 and 2012 is slightly below F pa and F MSY, but above the management plan target F. Management plans A longterm management plan was agreed by the EU, Faroe Islands, Iceland, Norway, and Russia in 1999 (Section Annex). The management plan aims to constrain harvesting within safe biological limits and is designed to ICES Advice 2013, Book 9 117

122 provide sustainable fisheries in the long term. ICES has evaluated the plan and concluded that it is consistent with the precautionary approach. Biology Norwegian springspawning herring is a widely migrating stock. The feeding grounds of the adults are in the Norwegian Sea. Spawning takes place in late winter and early spring along the Norwegian coast. In general, most juveniles occur in the Barents Sea and move to the Norwegian Sea when they mature. Environmental influence on the stock Norwegian springspawning herring migrations have been linked to changes in climate and to the distribution of zooplankton, the main prey of herring. The average biomass of zooplankton in the total area in May had a decreasing trend from around 2002 until 2009, but an upward trend since then. Over this period, no stockwide negative impact has been observed on herring condition, based on trends in weightatage. The fisheries In general, the fishery follows the migration of the stock as it moves from the wintering and spawning grounds along the Norwegian coast to the summer feeding grounds in the EU, Faroese, Icelandic, Jan Mayen, Svalbard, and international areas. The spatial distribution of the catches is shown in Figure There is little quantitative information on the bycatches in the fisheries for herring, but these are thought to be small in most fisheries, even though the recent expansion of the mackerel stock has resulted in mixed catches in some areas. Catch distribution Total catch (2012) = t, where 100% are landings (mainly purseseiners and pelagic trawls). Discards are considered to be low, but some slippage is known to occur. Effects of the fisheries on the ecosystem Little information is available on the impact of the herring fishery on the ecosystem. However, research evaluating the impacts is ongoing (ICES WGINOR). The fishery is entirely pelagic and thus not impacting the benthic habitat. Quality considerations Previous assessments have shown a retrospective pattern that overestimates SSB and underestimates F; this is also the case with the present assessment, but to a much smaller extent. Estimates of recruiting yearclass strength are uncertain. However, all available information indicates that year classes after 2004 are weak. Recent recruitment estimates do not have a large influence on the predicted yields and SSBs in the shortterm forecasts. Preliminary exploration of data indicates that change of catchability of herring in the main survey in relation to changes in the behaviour of herring could explain (part of) the retrospective behaviour of the assessment. Further studies are planned in the ICES benchmark process. Figure Herring in Subareas I, II, and V, and in Divisions IVa and XIVa (Norwegian springspawning herring). Historical assessment results (finalyear recruitment estimates included). 118 ICES Advice 2013, Book 9

123 Scientific basis Assessment type Input data Agebased analytical (TASACS). Assessment period : Commercial catches (international landings, ages, and weightatage from catch sampling). Eight survey indices: one larval survey (NHLS), two recruitment surveys (indices from EcoNoRuQ3 (Ace), and for surveys covering the adult stock, including one survey which provides an index of the abundance of young herring in the Barents Sea (including IESNS). No commercial indices, Maturity ogive variable by yearclass strength, Natural mortalities are fixed values from historical analyses. Discards are not included and are considered negligible. None. Discards and bycatch Indicators Other information This stock was benchmarked in Working group report WGWIDE 2013 (ICES, 2013b). ICES Advice 2013, Book 9 119

124 Supporting information October 2013 ECOREGION STOCK Widely distributed and migratory stocks Herring in Subareas I, II, and V, and in Divisions IVa and XIVa (Norwegian springspawning herring) Reference points Type Value Technical basis Management SSB MP 5.0 million t Mediumterm simulations conducted in plan F MP Mediumterm simulations conducted in MSY MSY B trigger 5.0 million t B pa Approach F MSY 0.15 Stochastic equilibrium analysis using a Beverton Holt stock recruitment relationship with data from 1950 to B lim 2.5 million t MBAL (accepted in 1998). Precautionary B pa 5.0 million t B lim exp( ). Approach F lim Not defined. F pa 0.15 Based on mediumterm simulations. (unchanged since: 2010) The fishing mortality reference points presented in the advice and used in management are the average of ages 5 14 weighted over the population numbers. The MSY and PA reference points have been reviewed by ICES in 2013 (ICES, 2013c) and kept unchanged. Outlook for 2014 Basis: F w(2013) 1) = 0.15; SSB (2014) = 4123 thousand tonnes; Recruitment ( ) = 79 billions (geometric mean recruitment ); Landings (2013) = 692 thousand tonnes (= sum of declared national quotas). % SSB % TAC Landings Rationale Basis Fw(2014) SSB(2015) change (2014) 2) change 3) Agreed management 419 F management plan plan MSY *F MSY Precautionary Even no fishing will bring 0 Approach SSB above Bpa Zero catch 0 F= Other options 588 F F management F management F management F management Management plan target F Landings and stock biomass weights in thousand tonnes. 1) Fw = Fishing mortality weighted by population numbers (age groups 5 14). Fw > FMP to account for expected catch in ) SSB 2015 relative to SSB ) Catch/landings 2014 relative to TAC Management plan Following the longterm management plan agreed by the EU, Faroe Islands, Iceland, Norway, and Russia implies a TAC of tonnes in This is expected to lead to an SSB of 3.5 million tonnes in MSY approach Following the ICES MSY framework implies a fishing mortality of (MSY B trigger/ssb(2014)*f msy) because SSB(2014) is below MSY B trigger, resulting in landings of tonnes in This is expected to lead to a decline in SSB in 2015 to 3.5 million tonnes. 120 ICES Advice 2013, Book 9

125 Fishing mortality in 2012 is below F MSY, therefore the transition scheme towards the ICES MSY framework does not apply. Precautionary approach The precautionary approach states that should the SSB fall below B pa the fishing mortality should be reduced to ensure a safe and rapid recovery of the B pa. Even zero catches in 2014 is expected to lead to a reduction in SSB in 2015 to 3.9 million tonnes. Additional considerations Ecosystem considerations Herring in the Northeast Atlantic is a widely distributed stock. Juveniles and adults of this stock form an important part of the ecosystem in the Northeast Atlantic. Herring are an important food resource for higher trophic level predators (e.g. large fish, seabirds, and marine mammals), and are also a consumer of zooplankton in the Norwegian Sea and a predator of capelin larvae in the Barents Sea. Management considerations The management plan for this stock is considered to be precautionary. Recent years have shown large downward revisions of the SSB in the assessment (Figure ). As a consequence the realized F values are higher than the management plan dictates, even though this plan has been followed. The shortterm prognoses indicate a decline in SSB from 5 million tonnes in 2013 to 4.1 and 3.5 million tonnes in 2014 and 2015, respectively, assuming that declared catches are taken in 2013 and exploitation in 2014 is in accordance with the management plan. The observed decline in the stock is consistent with previous assessments and forecasts; last year it was expected that the SSB in 2013 would decline to 5.1 million tonnes compared to this year s estimate of 5 million tonnes. Because the SSB in 2014 is assumed to be below B pa, the advice is based on article 3 of the management plan, which will be applied for the first time. As a result, the fishing mortalities will be lower than the target F MP of Given the low recruitment in recent years, it is expected that SSB will remain below B pa in the short term. This situation will continue until large year classes appear and recruit into the spawning stock, and because of the maturation taking place between the ages of 4 and 6 it will take at least four years until a strong year class contributes to an increase in the SSB. Surveys carried out in recent years in the Norwegian Sea and Barents Sea show no signs of new strong year classes after The extent of the present period of low recruitment is unknown and may continue for a number of years. An evaluation of the expected dynamics of the stock under continued poor recruitment conditions was presented in the ICES advice released earlier in 2013 (ICES, 2013c). This evaluation indicates that under the present management plan, in the absence of strong year classes, SSB is expected to fluctuate around 4 million tonnes and catches will vary between 300 and 400 thousand tonnes. In 2013, a lack of agreement by the Coastal States on their share in the TAC has led to unilaterally set quotas which together are higher than the TAC indicated by the management plan. If this situation continues, the high catches will accelerate the present decline of the stock and increase the risk of the stock going below B lim. In recent years the distribution area of mackerel has expanded to the north and west and now overlaps the distributional area of herring in summer. As a consequence, mackerel and herring catches are now mixed in these areas. This implies a potential for discarding. Data and methods The present assessment is an updated assessment, using the models, configurations, and procedures agreed at the benchmark held in 2008, with two exceptions. From 2010 onwards, new maturityatage information was used for the whole timeseries. This revision contributes to the change in perception of estimated SSB in the 2010 and later assessments compared to previous assessments. In 2013, an updated algorithm was implemented to derive the terminal fishing mortalities on the oldest age groups in the assessment for cohorts where there is insufficient information to estimate these. The new algorithm has increased the stability in the assessment. While discarding of this stock is considered to be low, slippage occurs. The amount of slippage is unquantified and thus cannot be accounted for in the assessment. ICES Advice 2013, Book 9 121

126 The International Ecosystem Survey in the Nordic Seas (IESNS) in May is the most important survey in the assessment and is expected to remain the main basis for future assessments. It is important that this survey be maintained and that the vessels participating in the survey have access to the survey grounds. It is essential to maintain good geographical survey coverage to avoid increases in assessment uncertainty and to maintain the integrity of the assessment. Uncertainties in assessment and forecast Applying the new algorithm for calculating terminal Fs significantly reduces the retrospective pattern in the earlier half of 1990s and reduces it to some degree in recent times. However, a strong retrospective pattern still remains in the recent assessments, with annual downward revisions. This pattern in the recent years is likely partly due to changes in survey catchability. This needs to be addressed in a benchmark. There is little uncertainty that year classes since 2005 are weak and that SSB has reduced and is expected to reduce further. Assumptions on recent recruitment have little impact on the prediction of the catch and the SSB in the projection. Comparison with previous assessment and advice A comparison between the assessments is shown in Figure This year s assessment is consistent with last year s assessment. In the current assessment, the SSB in 2012 is about 5% lower than estimated last year. The fishing mortality in 2010 is now estimated about 6% higher than in last year s assessment. The basis for advice is the same as last year, taking into account that the estimated SSB is below SSB MP. Sources ICES. 2013a. Report of the Blue Whiting/Norwegian SpringSpawning (AtlantoScandian) Herring Workshop (WKBWNSSH). ICES CM 2013/ACOM:69. ICES. 2013b. Report of the Working Group on Widely Distributed Stocks (WGWIDE), 27 August 02 September 2013, ICES Headquarters, Copenhagen. ICES CM 2013/ACOM:15. ICES. 2013c. NEAFC request to ICES to evaluate possible modifications of the longterm management arrangement for the Norwegian springspawning herring stock. In Report of ICES Advisory Committee, ICES Advice 2013, Book 9, Section ICES Advice 2013, Book 9

127 Figure Total reported catches of Norwegian springspawning herring in 2012 by quarter and ICES rectangle. Grading of the symbols: black dots less than 300 t, open squares t, and black squares > 3000 t. ICES Advice 2013, Book 9 123

128 Figure Herring in Subareas I, II, and V, and in Divisions IVa and XIVa (Norwegian springspawning herring). Historical perspective of the stock. Data from are from a previous assessment model that is no longer used. Data from 1988 to 2012 are from this year s assessment. Note that the SSB data prior to 1988 do not include the new maturity ogive. Figure Herring in Subareas I, II, and V, and in Divisions IVa and XIVa (Norwegian springspawning herring). Stock recruitment observations for ICES Advice 2013, Book 9

129 Table Herring in Subareas I, II, and V, and in Divisions IVa and XIVa (Norwegian springspawning herring). ICES advice, management, and catches. Year ICES Advice Predicted catch corresp. to advice Agreed TAC ICES Catch 1987 TAC TAC TAC TAC No fishing from a biological point of view No fishing from a biological point of view No increase in F Gradual increase in F towards F 0.1; TAC suggested No increase in F 513 None Keep SSB above 2.5 million t None Keep SSB above 2.5 million t Do not exceed the harvest control rule Do not exceed the harvest control rule Do not exceed the harvest control rule Max Do not exceed the harvest control rule Do not exceed the harvest control rule Do not exceed the harvest control rule Do not exceed the harvest control rule Do not exceed the harvest control rule Do not exceed the harvest control rule Do not exceed the harvest control rule Do not exceed the harvest control rule Do not exceed the harvest control rule Do not exceed the harvest control rule See scenarios Follow the management plan Follow the management plan Follow the management plan Weights in thousand tonnes. 1 Autonomous TACs totaling t. 2 Autonomous TACs totaling t were set by April There was no agreement on the TAC, the number is the sum of autonomous quotas from the individual Parties. 4 Revised in Sum of the national quotas. ICES Advice 2013, Book 9 125

130 Table Herring in Subareas I, II, and V, and in Divisions IVa and XIVa (Norwegian springspawning herring). Total catch (tonnes) since Data provided by Working Group members. YEAR NORWAY USSR/ DENMARK FAROES ICELAND IRELAND NETHERLANDS GREENLAND UK (SCOTLAND) GERMANY FRANCE POLAND SWEDEN TOTAL RUSSIA * ** *In 2003 the Norwegian catches were raised by tonnes to account for changes in percentages of water content. **Scotland and Northern Ireland combined.

131 Table Herring in Subareas I, II, and V, and in Divisions IVa and XIVa (Norwegian springspawning herring). Summary of the stock assessment. Weighted F with stock numbers Year Recruit TSB SSB Landings Unweighted Age 0 in Million Million billions tonnes tonnes tonnes F 5 14 WF * * The GM recruitment over the years is 79 billion. ICES Advice 2013, Book 9 127

132 Annex The EU, Faroe Islands, Iceland, Norway, and Russia agreed in 1999 on a longterm management plan. This plan consists of the following elements: 1. Every effort shall be made to maintain a level of Spawning Stock Biomass (SSB) greater than the critical level (B lim) of t. 2. For the year 2001 and subsequent years, the Parties agreed to restrict their fishing on the basis of a TAC consistent with a fishing mortality rate of less than for appropriate age groups as defined by ICES, unless future scientific advice requires modification of this fishing mortality rate. 3. Should the SSB fall below a reference point of t (B pa), the fishing mortality rate referred to under paragraph 2, shall be adapted in the light of scientific estimates of the conditions to ensure a safe and rapid recovery of the SSB to a level in excess of t. The basis for such an adaptation should be at least a linear reduction in the fishing mortality rate from at B pa ( t) to 0.05 at B lim ( t). 4. The Parties shall, as appropriate, review and revise these management measures and strategies on the basis of any new advice provided by ICES. 128 ICES Advice 2013 Book 9

133 Advice October 2013 ECOREGION STOCK Widely distributed and migratory stocks Horse mackerel (Trachurus trachurus) in Divisions IIa, IVa, Vb, VIa, VIIac, ek, and Subarea VIII (Western stock) Advice for 2013 ICES advises on the basis of the MSY approach that landings in 2014 should be no more than t. Even though some discards are included in the assessment, the total amount of discards cannot be quantified. Therefore total catches cannot be calculated. Stock status MSY (FMSY) Precautionary approach (Fpa,Flim) MSY (Btrigger) Precautionary approach (Bpa,Blim) Qualitative evaluation F (Fishing Mortality) Above target Undefined SSB (SpawningStock Biomass) Undefined Undefined declining Figure Horse mackerel in Divisions IIa, IVa, Vb, VIa, VIIa c,e k, and VIIIa e (Western stock). Summary of stock assessment (weights in thousand tonnes; the estimated shaded recruitment 2013 is the geometric mean of ). Top right: SSB and F timeseries. The SSB, which has varied between 0.65 and 1.72 million tonnes during , is estimated to be at 0.84 million tonnes in Fishing mortality has been increasing since 2007 and is now above F MSY. Recruitment has been low from 2004 onwards. Management plans In 2007, a management plan based on the triennial egg survey was proposed by the Pelagic RAC (Section Annex) and has been used by the EU since 2008 to set the EU TAC. The management plan was initially appraised by ICES Advice 2013, Book 9 129

134 ICES in 2007 and was deemed to be precautionary in the short term only, because some relevant scenarios were not evaluated. Further evaluation in 2013 suggests that in its current configuration the HCR is not robust to more than 2 years of very low recruitment (ICES, 2013b). Biology The western horse mackerel stock extends from Subarea VIII in the south to Division IIa in the north, except for the North Sea which is considered a separate stock. However, the western stock is also considered to extend into Divisions IVa and IIIa in quarters 3 and 4. Horse mackerel recruitment is characterized by infrequent extremely large year classes. There is evidence that horse mackerel fecundity is not determinate and this might create uncertainties in the relationship between SSB and egg abundance. Environmental influence on the stock Since 1987, when the strong 1982 year class of the western stock first began to appear in the North Sea, there has been a good correspondence in most years between the influx of Atlantic water to the North Sea in the first quarter and the horse mackerel catches by Norwegian purseseiners in the Norwegian EEZ (NEZ) during the late (October November) period of the same year (Iversen et al., 2002, 2007). It is unclear whether the strong relationship between influx of Atlantic water and the occurrence of horse mackerel in NEZ still holds, since in recent years horse mackerel has occurred together with mackerel in this area and Norwegian fishers have avoided fishing horse mackerel there. The fisheries There are several fisheries for horse mackerel. The adults are caught in targeted fisheries to the west, and as target species and bycatch in the south, while a juvenile fishery has historically occurred mainly in Divisions VIIe h and VIIIa d. This juvenile fishery developed in 1993 and reached a peak in 2003, but has declined as a proportion of the overall catch in the past ten years. The proportion of juveniles in the fishery from this area has been variable in the past ten years, reaching a peak of about 10% (by weight) in 2010 and declining since then. Catch distribution Total catch (2012) = tonnes (mainly pelagic trawl); discards are underestimated, with discards data available for some of the main fleets. Quality considerations There is large uncertainty in the absolute estimates of SSB. The only fisheryindependent information for this stock is a measure of egg production from surveys conducted every three years. The assessment assumes that fecundityatsize varies with no trend over time. If this assumption is incorrect, then the assessment results may also be biased. Discards are included in the assessment. However, not all countries provide data on discards; consequently, there is no estimate of the total amount of discards in the horse mackerel fisheries. The landings fraction sampled to estimate biological parameters has been declining in recent years; it is important to keep those levels on target. As in previous years, and despite the data sampling regulations for EU countries, some countries with major catches have not conducted biological sampling programmes. Figure Horse mackerel in Divisions IIa, IVa, Vb, VIa, VIIa c,e k, and VIIIa e (Western stock). Historical assessment results (finalyear recruitment estimates included). The fishing mortality age ranges for the 2008 and 2009 assessment years were calculated using ages 4 8, while for the 2010 and 2011 assessments, ages 1 10 were used. The dotted line corresponds to the FMSY reference point. 130 ICES Advice 2013 Book 9

135 Scientific basis Assessment type Input data Discards and bycatch Indicators Other information Working group report Agebased analytical (Linked Separable Adapt VPA). Commercial catches: international catches and ages from catch sampling. One survey index: Triennial egg survey index. One tuning index: potential fecundity vs fish weight 1987, 1992, 1995, 1998, 2000, Annual maturity data: constant since Natural mortalities: a constant value (0.15) was used. Discard data are available for some of the main fleets. Discards were included in the assessment for some years, from Dutch, Spanish, Irish, and German fleets. None. None. WGWIDE (ICES, 2013a). ICES Advice 2013, Book 9 131

136 Supporting information October 2013 ECOREGION STOCK Widely distributed and migratory stocks Horse mackerel (Trachurus trachurus) in Divisions IIa, IVa, Vb, VIa, VIIa c,e k, and VIIIa e (Western stock) Reference points Type Value Technical basis MSY MSY B trigger Not defined. Approach F MSY 0.13 F 0.1 from the yieldperrecruit (Section 5.7 in ICES, 2010). B lim Not defined. 1) Precautionary B pa Not defined. 1) Approach F lim Not defined. F pa Not defined. (unchanged since: 2013) 1) Previous PA biomass reference points were considered not consistent with the perceived state of the stock, the exploitation rate, and the evaluation of MSY reference points. Outlook for 2014 Basis: Catch (2013) = 183 (EU TAC); F 2013 = 0.19; R ( ) = 2.3 billion (GM ); SSB (2013) 1) = Rationale Catch (2014) Basis F (2014) SSB (2014) 1) SSB (2015) 1) %SSB change 2) % TAC change 3) MSY approach F MSY Zero catch 0 F = Management plan Management plan Other options % TAC reduction (F ) % TAC reduction (F ) F Rollover TAC (TAC 2013) 15% TAC increase (F ) 20% TAC increase (F ) Weights in thousand tonnes. 1) SSB at spawning time. 2) SSB 2015 relative to SSB 2014 at spawning time. 3) Catch 2014 relative to TAC MSY approach Following the ICES MSY approach requires fishing mortality to be reduced to 0.13 in 2014, resulting in catches of less than tonnes in This is expected to lead to an SSB of 554 kt in ICES Advice 2013 Book 9

137 Management plan ICES does not advise according to the management plan because it has recently concluded that, in its current configuration, the HCR is not consistent with the PA (ICES, 2013c). However, this work also showed that the plan could be made consistent with the PA through the introduction of a biomass trigger in the HCR (ICES, 2013b). Thus, ICES advises that these modifications to the HCR would need to be made before the plan is used to give catch advice. Additional considerations Note that the TAC advice based on the MSY approach results in a lower SSB in 2015 than the lowest SSB in the timeseries, and it is uncertain if this low SSB will lead to reduced recruitment. The TAC should apply to all areas where Western horse mackerel is caught. The advice for horse mackerel assumes that all landings are counted against the TAC for each stock separately. Western horse mackerel are taken in a variety of fisheries for human consumption, with juvenile fish directed mostly at the Japanese market and large fish at the African market. Since 2003, the fishery has been more directed toward younger fish (ages 1 3) than fish of ages 4 to 8. In 2012, fishing mortality on younger ages reached a recordhigh level. Data and methods The assessment is carried out with some discards included; however, discards for 2012 were not included in this year s assessment. The raising methodology for international landings this year was carried out using InterCatch whereas in previous years landings were raised using Salloc. The effect of the change in raising methodology was not assessed during this year s working group due to limited time so there is uncertainty in the potential differences in the 2012 catchatage data used in the assessment. Management considerations The 2001 year class has now entered the plus group and there are no detectable strong year classes entering the fishery. This year a preliminary egg abundance estimate is available from the 2013 egg survey that has changed the perception of the stock. However, the declining trend in SSB and upward trajectory of F 110 remains the same. SSB in 2013 was estimated at 0.84 Mt, among the lowest in the timeseries. The shortterm forecast of SSB and yield obtained this year show a declining SSB in 2015 relative to SSB in This applies to all options, including zero catches which results in a 7% reduction. The assessment estimate of SSB is very uncertain, and historically it has revised the perception of the development of the stock over time. The assessment has no independent information to determine whether increased proportions of young fish in the catches are due to increased mortality or increased recruitment. Currently this situation is explained as increased mortality in the assessment, implying low recruitment. When a new survey index is introduced to the data every three years (as in 2013) the assessment is rescaled to the most recent survey observation. The effect of this rescaling is to significantly change the yield advice and the perception of mortality in the stock. Comparison with previous assessment SSB in 2012 has been revised down by 36%. Fishing mortality in 2011 for ages 1 10 has been revised upward by 25%. The estimated catch for 2012 in last year s forecast was overestimated by 5%. Sources ICES Report of the Working Group on Widely Distributed Stocks (WGWIDE), 28 August 3 September 2010, Vigo, Spain. ICES CM 2010/ACOM:12. ICES Report of the Working Group on Mackerel and Horse Mackerel Egg Surveys (WGMEGS), April 2011, San Sebastian, Spain. ICES CM 2011/SSGESST: pp. ICES Report of the Working Group on Widely Distributed Stocks (WGWIDE), August 2012, Lowestoft, UK. ICES CM 2012/ACOM:16. ICES. 2013a. Report of the Working Group on Widely Distributed Stocks (WGWIDE), 27 August 02 September 2013, ICES Headquarters, Copenhagen, Denmark. ICES CM 2013/ACOM:15. ICES. 2013b. Report of the Workshop to evaluate the EU management plan for Western horse mackerel (WKWHMAC), June 2013, ICES Headquarters, Copenhagen, Denmark. ICES CM 2013/ACOM:59. ICES Advice 2013, Book 9 133

138 ICES. 2013c. EC request to ICES to evaluate possible modifications of the longterm management arrangement for the Western horse mackerel stock. In Report of ICES Advisory Committee, ICES Advice 2013, Book 9, Section Iversen, S. A., Skogen, M. D., and Svendsen, E Availability of horse mackerel (Trachurus trachurus) in the northeastern North Sea, predicted by the transport of Atlantic water. Fisheries Oceanography, 11(4): Iversen, S. A., Skogen, M., and Svendsen, E A prediction of the Norwegian catch level of horse mackerel in In Report of the Working Group on the Assessment of Mackerel, Horse Mackerel, Sardine, and Anchovy (WGMHSA), 4 13 September 2007, ICES Headquarters, Copenhagen, Denmark. ICES CM 2007/ACFM: pp. 134 ICES Advice 2013 Book 9

139 Figure Horse mackerel (Trachurus trachurus) in Divisions IIa, IVa, Vb, VIa, VIIa c,e k, and VIIIa e (Western stock). Stock recruitment (left panel) and yieldperrecruit plot (right panel). Table Horse mackerel (Trachurus trachurus) in Divisions IIa, IVa, Vb, VIa, VIIa c,e k, and VIIIa e (Western stock). ICES advice, management, landings, discards, and catches. Year ICES Advice Predicted catch corresp. to advice 2 Agreed TAC 1 ICES Landings 2 Disc. Slip 2 ICES Catch Not assessed No increase in catches If sustained catches required; TAC TAC ~ Within safe biological limits Within safe biological limits Within safe biological limits Prudent not to increase F Reduction in catch Reduction in catch Reduction in F Reduction in F to Effectively limit catches to t < Effectively limit catches to t < Effectively limit catches to t < Effectively limit catches to t < Effectively limit catches to t < Limit catches to less than t < Limit catches to less than t < Limit catches to less than t < Limit catches to less than t < Follow proposed management plan Follow proposed management plan Follow proposed management plan See scenarios MSY framework MSY framework MSY approach Weights in thousand tonnes Applies to EU waters only Divisions IIa, IVa, Vb, VIa, VIIa c, VIIe k, and VIIIa,b,d,e Including Division VIIIc For the whole distribution area. ICES Advice 2013, Book 9 135

140 6. Table Horse mackerel (Trachurus trachurus) in Divisions IIa, IVa, Vb, VIa, VIIa c,e k, and VIIIa e (Western stock). Horse mackerel landings (t) in Subarea II. (Data as submitted by Working Group members.) Country Denmark 39 France Germany, Fed. Rep + Norway ,272 USSR Total , Faroe Islands ,115 9, , Denmark 200 France 2 55 Germany, Fed. Rep Norway 6,285 4,770 9,135 3,200 4,300 2, ,300 USSR (Russia from 1992 on) , ,633 UK (England + Wales) 17 Total 6,818 4,809 11,414 4,487 13,457 3, , Faroe Islands 1, Denmark 1,755 3 France Germany Norway 887 1, , , Russia UK (England + Wales) Estonia 22 Total 3,366 2,617 2,544 2,557 1, , Faroe Islands Denmark France + Germany Ireland Netherlands 1 Norway ,847 1, Russia UK (England + Wales) Estonia Total ,847 4, Preliminary. 2 Included in Subarea IV. 3 Includes landings in Division Vb. 4 Taken in Division Vb. 136 ICES Advice 2013 Book 9

141 Table Horse mackerel (Trachurus trachurus) in Divisions IIa, IVa, Vb, VIa, VIIa c,e k, and VIIIa e (Western stock). Horse mackerel landings (t) in the North Sea (Subarea IV and Skagerrak Division IIIa) by country (data submitted by Working Group members). Catches partly concern the North Sea horse mackerel. Country Belgium Denmark Faroe Islands France Germany, Fed. Rep. Ireland Netherlands Norway 2 Poland Sweden UK (Engl. + Wales) UK (Scotland) USSR , , , , , , , , , , , , , , ,749 Total 2,151 7,253 2,788 4,420 25,987 24,238 20,808 20,895 62,877 Country Belgium Denmark Estonia Faroe Islands France Germany, Fed. Rep. Ireland Netherlands Norway Poland Sweden UK (Engl. + Wales) UK (N. Ireland) UK (Scotland) USSR (Russia from 1992 on) Unallocated + discards 10 23, ,172 84, ,093 12, , , , , , ,995 2,657 3,852 50, , , ,801 2,600 3,000 96, , ,570 4,086 2, , ,059 3, , , ,329 94,000 2, ,582 1, , , ,285 84, , , ,100 6,205 14, , ,603 8,152 37,778 45, ,511 31,615 Total 112, ,062 77, , , ,580 98,452 26,125 79,161 Country Belgium Denmark Estonia Faroe Islands France Germany Ireland Lithuania Netherlands Norway Russia Sweden UK (Engl. + Wales) UK (Scotland) Unallocated+discards 19 2, ,620 3,811 13,129 3, , , , ,610 44,344 1, , , , ,382 1, , , , ,685 7, , ,004 1, , ,612 35, , , , ,354 20,493 1,074 1, , , , ,418 10, , , , ,876 1, ,679 24, , , ,343 2, ,077 2,354 20,984 27, ,623 Total 31,247 64, ,839 49,691 34,226 30,435 40,564 38,911 ICES Advice 2013, Book 9 137

142 Table cont. Horse mackerel (Trachurus trachurus) in Divisions IIa, IVa, Vb, VIa, VIIa c,e k, and VIIIa e (Western stock). Horse mackerel landings (t) in the North Sea (Subarea IV and Skagerrak Division IIIa) by country (data submitted by Working Group members). Catches partly concern the North Sea horse mackerel. Country Belgium Denmark Faroe Islands France Germany 93 1,167 1, Ireland 652 1, Netherlands 20,027 9,400 10,077 1, Lithuania 98 Norway ,745 11,082 13,409 3,183 Sweden UK (Engl. + Wales) 2,966 UK (Scotland) Unallocated +discards 14,403 9,151 5,898 0 Total 16,407 15,377 78,595 13,667 14,725 3,321 1 Preliminary. 2 Includes Division IIa. 3 Estimated from biological sampling. 4 Assumed to be misreported. 5 Includes 13 t from the German Democratic Republic. 6 Includes negative unallocated landings of 4000 t. Table Horse mackerel (Trachurus trachurus) in Divisions IIa, IVa, Vb, VIa, VIIa c,e k, and VIIIa e (Western stock). Horse mackerel landings (t) in Subarea VI by country (data submitted by Working Group members). Country Denmark , ,655 Faroe Islands 1,248 4,014 1,992 4, ,000 3 France Germany, Fed. Rep. 5,550 10,212 2,113 4, Ireland 15,086 13,858 27,102 28,125 29,743 27,872 Netherlands 2, ,500 18,450 3,450 5,750 3,340 Norway Spain UK (Engl. + Wales) UK (N. Ireland) UK (Scotland) , ,027 7,834 USSR. Unallocated + disc 19,168 13,897 7,255 Total 8,724 11,134 6,283 19,381 31,716 33,025 20,455 35,157 45,842 Country Denmark Faroe Islands 3, France Germany, Fed. Rep. 1,162 2,474 2,500 6,281 10,023 1,430 1, Ireland 19,493 15,911 24,766 32,994 44,802 65, ,124 87,872 22,474 Netherlands 1, ,369 2, , Norway Spain UK (Engl. + Wales) , UK (N.Ireland) 1, UK (Scotland) 1, , ,523 1, ,669 14,452 USSR/Russia (1992) 44 Unallocated + disc. 6, ,278 1,940 6, ,326 11, Total 34,870 20,904 34,456 40,469 53,942 69,527 83,595 81,259 40, ICES Advice 2013 Book 9

143 Table cont. Horse mackerel (Trachurus trachurus) in Divisions IIa, IVa, Vb, VIa, VIIa c,e k, and VIIIa e (Western stock). Horse mackerel landings (t) in Subarea VI by country (data submitted by Working Group members). Country Denmark Faroe Islands France , Germany 414 1, ,337 1,413 1,958 1,025 Ireland 21,608 31,736 15,843 20,162 12,341 20,915 15,702 12,395 9,780 Lithuania 2,822 Netherlands 885 1, ,701 6,039 1,892 Spain UK (Engl.+Wales) UK (N.Ireland) 1, UK (Scotland) 10,447 4,544 1,839 3,111 1, Unallocated+disc. 98 1,507 2, , Total 34,815 65,308 20,657 24,636 14,190 23,254 21,929 22,055 15,751 Country Denmark Faroe Islands France Germany 1,835 5, , Ireland 20,341 18,786 16,565 19,985 23,556 29,283 Lithuania Netherlands 2,177 3,904 2,332 1,685 6,353 12,653 Norway Russia Spain UK (Engl. + Wales) 232 UK (Scotland) ,528 1,232 Unallocated+disc. 1,474 3,781 2, Total 26,279 25,902 17,776 22,613 39,528 44,975 1 Preliminary. 2 Included in Subarea VII. 3 Includes Divisions IIIa, IVa,b, and VIb. 4 Includes negative unallocated landings of 7000 t. 5 French catches landed in the Netherlands. ICES Advice 2013, Book 9 139

144 Table Horse mackerel (Trachurus trachurus) in Divisions IIa, IVa, Vb, VIa, VIIa c,e k, and VIIIa e (Western stock). Horse mackerel landings (t) in Subarea VII by country (data submitted by the Working Group members). Country Belgium Denmark 5,045 3, , , ,368 33,202 France 1,983 2,800 2,314 1,834 2,387 1,881 3,801 2,197 1,523 Germany, Fed.Rep. 2,289 1, , ,705 Ireland Netherlands 23,002 25,000 27, ,350 38,700 33,550 40,750 69,400 43,560 Norway 394 Spain UK (Engl. + Wales) 12,933 2,520 2,670 1, ,630 1,824 1,228 3,759 UK (Scotland) ,873 USSR 120 Total 45,697 34,749 33,478 40,526 42,952 39,034 77, ,734 90,253 Country Faroe Islands 28 Belgium Denmark 34,474 30,594 28,888 18,984 16,978 41,605 28,300 43,330 60,412 France 4,576 2,538 1,230 1,198 1,001 27,201 Germany, Fed.Rep. 7,743 8,109 12,919 12,951 15,684 14,828 17,436 15,949 28,549 Ireland 12,645 17,887 19,074 15,568 16,363 15,281 58,011 38,455 43,624 Netherlands 43, , , , ,110 92, , ,692 81,464 Norway Spain UK (Engl. + Wales) 4,488 13,371 6,436 7,870 6,090 12,418 31,641 28,605 17,464 UK (N.Ireland) 2,026 1, ,093 UK (Scotland) ,992 5,008 3,123 9,015 10,522 11,241 7,931 USSR / Russia (1992) Unallocated + discards 28,368 7,614 24,541 15,563 4, ,057 68,644 26,795 58,718 Total 135, , , , , , , , ,474 Country Faroe Islands 550 3,660 1,201 Belgium Denmark 25,492 19,223 13,946 20,574 10,094 10,867 11,529 9,939 6,838 France 24,223 20,401 11,049 6,466 7,199 8,083 8,469 7,928 Germany 25,414 15,247 9,692 8,320 10,812 13,873 16,352 10,437 7,139 Ireland 51,720 25,843 32,999 30,192 23,366 13,533 8,470 20,406 16,841 Lithuania 3,569 Netherlands 91,946 56,223 50,120 46,196 37, ,123 31,156 35,467 Spain UK (Engl. + Wales) 12,832 8,885 2,972 8,901 5,525 4,186 7,178 4,752 2,935 UK (N.Ireland) UK (Scotland) 5,095 4,994 5,152 1,757 1, , Unallocated+discards 12,706 31,239 1,884 11,046 2,576 24,897 18,485 18,368 19,379 Total 249, , , ,042 97, , , , , ICES Advice 2013 Book 9

145 Table cont. Horse mackerel (Trachurus trachurus) in Divisions IIa, IVa, Vb, VIa, VIIa c,e k, and VIIIa e (Western stock). Horse mackerel landings (t) in Subarea VII by country (data submitted by the Working Group members). Country Faroe Islands Belgium Denmark 4,806 1,970 2,710 5,247 5,831 2,281 France 6,844 11, Germany ,700 14,204 20,404 14,545 16,391 Ireland 8,039 16,293 23,841 24,490 14,154 15,893 Lithuania 5,585 4,907 Netherlands 38,034 43,514 47,741 75,475 49,207 53,644 Norway 40 Spain Sweden 55 UK (Engl. + Wales) 9,105 11,688 12,122 UK (Scotland) ,123 1, Unallocated+discards 15,460 14, , Total 93,084 98,746 89, , , ,098 1 Preliminary. 2 Includes landings from Subarea VI. ICES Advice 2013, Book 9 141

146 Table Horse mackerel (Trachurus trachurus) in Divisions IIa, IVa, Vb, VIa, VIIa c,e k, and VIIIa e (Western stock). Horse mackerel landings (t) in Subarea VIII by country. (Data submitted by Working Group members). Country Denmark 446 3,283 2,793 France 3,361 3, ,643 2,489 4,305 3,534 3,983 4,502 Netherlands Spain 34,134 36,362 19,610 25,580 23,119 23,292 40,334 30,098 26,629 UK (Engl.+Wales) USSR Total 37,495 40,073 22,684 28,223 25,629 27,740 45,362 37,703 34,177 Country Denmark 6,729 5,726 1,349 5,778 1, France 4,719 5,082 6,164 6,220 4, ,690 Germany, Fed. Rep Netherlands 6,000 12,437 9,339 19,000 7,272 14,187 2,944 Spain 27,170 25,182 23,733 27,688 27,921 25,409 28,349 29,428 31,081 UK (Engl.+Wales) USSR/Russia (1992) Unallocated+discards 1,500 2,563 5, ,038 3,583 2,944 Total 38,686 43,496 46,396 54,186 53,709 35,500 28,709 48,269 40,930 Country Denmark 1,728 4,818 2, ,513 France 1, ,316 13,676 2,161 3,540 3,944 Germany 3,268 3,197 3,760 3,645 2,249 4, ,776 3,325 Ireland 6,485 1, ,882 1, Lithuania 401 Netherlands 6,604 22,479 11,768 36,106 12,538 1,314 1,047 6,607 6,073 Russia 6,620 Spain 23,599 24,190 24,154 23,531 22,110 24,598 16,245 16,624 13,874 UK (Engl. + Wales) , UK (Scotland) 249 Unallocated+discards 1, ,093 4,365 1,705 2,785 2,202 7,302 4,013 Total 38,936 46,129 54,212 76,120 54,560 41,711 24,125 41,495 34,122 Country Denmark 2,687 3,289 3, France 10,741 2, Germany Ireland Lithuania Netherland 6,269 1, Russia Spain 13,853 19,840 21,071 38,740 34,581 13,502 UK (Engl. + Wales) 28 UK (Scotland) Unallocated+discards ,045 3, Total 28,387 33,892 33,355 43,227 35,245 17,402 1 Preliminary. 2 Included in Subarea VII. 3 French landings landed in the Netherlands. 142 ICES Advice 2013 Book 9

147 Table Horse mackerel (Trachurus trachurus) in Divisions IIa, IVa, Vb, VIa, VIIa c, e k, and VIIIa e (Western stock). National catches of the Western horse mackerel stock (in tonnes). Country Belgium Denmark 62,897 29,542 22,663 13,084 6,108 10, ,480 1,021 Estonia Faroe Islands 1, ,847 3,695 France 39,188 24,267 25,141 20,457 15,145 18,951 10,383 8,060 10,690 Germany 28,533 27,872 17,629 13,348 11,493 12,614 15,826 17,830 16,734 Ireland 74,250 70,811 57,956 55,300 51,874 36,483 35,855 26,431 35,361 Lithuania Netherlands 82,885 92,535 75,333 57,971 73,439 42,019 47, ,445 Norway 45,058 13,363 46,410 2,087 7,956 36,689 20, ,113 Russia Spain 31,087 14,882 25,123 22,669 23,053 23,214 24,588 16,272 16,636 Sweden 1, ,952 1, , UK (Engl. + Wales) 19,778 12,162 9,257 1,555 7,096 5,971 4,440 4,617 3,560 UK (N. Ireland) 1, UK (Scotland) 32,865 18,283 11,197 7,230 8,029 2, , Unallocated 48,732 20,145 4, ,794 3,710 17,905 15,256 24,263 Discard 2, Total 471, , , , , , , ,994 Country Belgium Denmark 8,353 7,617 5,261 6,009 5,941 6,109 4,002 Estonia Faroe Islands 1, France 11,034 12,748 12, ,271 1,795 Germany 10,863 5,784 11,708 15,121 17,688 21,114 17,063 Ireland 26,779 30,091 35,612 40,754 44,488 38,464 45,242 Lithuania 6,829 5,467 5,548 Netherlands 37,130 29,083 43,648 39,451 61,504 55,692 66,396 Norway 27,114 4,182 1,223 59,764 11,978 13,755 3,251 Russia Spain 13,878 14,257 19,851 21,077 38,744 34,581 13,560 Sweden UK (Engl. + Wales) 3,583 5,482 3,365 6,482 12,714 11,716 12,122 UK (N. Ireland) 224 UK (Scotland) ,077 1,413 2,348 2,928 1,335 Unallocated 7,534 7,263 2,294 7,010 7,237 5,095 Discard ,846 6,522 3,280 Total 155, , , , , , ,141 ICES Advice 2013, Book 9 143

148 Table Horse mackerel (Trachurus trachurus) in Divisions IIa, IVa, Vb, VIa, VIIa c, e k, and VIIIa e (Western stock). Timeseries of egg production estimates (10 12 eggs). Year Total egg production ICES Advice 2013 Book 9

149 Table Horse mackerel (Trachurus trachurus) in Divisions IIa, IVa, Vb, VIa, VIIa c, e k, and VIIIa e (Western stock). Summary of stock assessment. R (age 0) SSB TSB Catch Yield/SSB F(13) F(48) F(110) (thousands) (tons) (tons) (tons) Note: the final estimate of SSB assumes the same Fatage as in the preceding year R(age 0) in 2011 and 2012 is the geometric mean of the timeseries 1983 to ICES Advice 2013, Book 9 145

150 Annex Extract from the plan agreed by the Executive Committee of the Pelagic RAC on the 13 July for submission to the European Commission. 1. General provisions The parties agree on a management plan for the western horse mackerel stock, with the following general provisions: The plan provides for conditions for sustainable long term yield for the stock. The plan provides for achievement of acceptable year to year stability in the TAC. A unified management regime across all areas where the stock is distributed. That there are not additional catches to those covered by the TAC. The industry agrees to partake in studies to demonstrate that there are no additional catches above the level of the TAC. Productivity of the stock assumed to reflect the conditions of the period 1982 to However, the plan was tested under conditions where no strong year classes of the magnitude of the 1982 year class occur. That the TAC is set on a triennial basis on egg abundance from the most recent three surveys. Target fisheries will proceed with minimum ecological impact. The industry undertakes to partake in studies to quantify the levels of the nontarget bycatch. 2. Normal decision rule For 2008 and subsequent years the TAC will be set according to the following rules: 1. The TAC will be set for 3 years following the years of the most recent survey. 2. The TAC will be fixed at the set level for a period of 3 years. 3. In the event of the TAC being overshooting in any year in the fixed period, the overshoot (as estimated by ICES) will be subtracted from the following years TAC. This needs to be tested by simulation. 4. In the event of a survey results not being available, ICES will asked to advise on the state of the stock and the exploitation boundaries with the Precautionary Approach. 5. The TAC will be set according to the following rule: 3. TAC y+ 1to y+ 3 TAC = ref TACy to y sl Where y is the year an egg survey becomes available, TAC ref = 150,000 t and sl is a function of the slope of the most recent egg abundance estimates from surveys. Arrangements for reviewing the decision rules: The plan will be reviewed and reevaluated in 2009 and on the three yearly intervals thereafter to ensure that: 1. SSB has been maintained above SSB That the uncertainties and bias in the fishery and biological system remain within the bounds of those tested, and that the assumptions made in the simulation testing phase are still valid. If either of the above has been violated the plan will be modified to adapt the decision rule to make it consistent with the Precautionary Approach. Special conditions to apply in times of high stock productivity 146 ICES Advice 2013 Book 9

151 If a recruitment event is the same or greater than that which occurred in 1982, as determined by ICES, the following will apply: The detection of the recruitment event will be established no sooner than 4 years after its occurrence. The level of the recruitment will be established based on ICES interpretation of the most valid assessment. After verification of such an event, by ICES, the decision rule will be adapted for as long as that year class contributes to the stock and the fisheries. ICES is asked to develop a metric to determine the duration this period of elevated productivity. Such metric would identify when the terms of the normal decisions rule above will be reverted to. ICES Advice 2013, Book 9 147

152 Advice October 2013 ECOREGION STOCK Widely distributed and migratory stocks Kitefin shark (Dalatias licha) in the Northeast Atlantic Advice for 2014 The advice given in 2012 for this stock is biennial and valid for 2013 and 2014 (see ICES, 2012a): ICES advises on the basis of the precautionary approach that no targeted fisheries should be permitted unless there are reliable estimates of current exploitation rates and sufficient data to assess productivity. There should be no fisheries unless there is evidence that this will be sustainable. The advice is summarized in the table below. Sources ICES. 2012a. Kitefin shark (Dalatias licha) in the Northeast Atlantic. In Report of the ICES Advisory Committee 2012, Section ICES Advice, Book 9: ICES. 2012b. Report of the Working Group on Elasmobranch Fishes (WGEF), June 2012, Lisbon, Portugal. ICES CM 2012/ACOM: pp, Section 4. Table Kitefin shark (Dalatias licha) in the Northeast Atlantic. ICES advice, management, and landings. Year ICES Advice Predicted catch corresponding to advice Agreed TAC Subarea X Agreed TAC Subarea XII ICES landings 1992 No advice No TAC No TAC No advice No TAC No TAC No advice No TAC No TAC No advice No TAC No TAC No advice No TAC No TAC No advice No TAC No TAC No advice No TAC No TAC No advice No TAC No TAC No advice No TAC No TAC No advice No TAC No TAC No advice No TAC No TAC No advice No TAC No TAC No advice No TAC No TAC No advice No TAC No TAC No target fisheries No TAC No TAC No target fisheries No new advice, same as for No target fisheries No new advice, same as for No target fisheries No new advice, same as for No target fisheries No new advice, same as for Weights in tonnes. 148 ICES Advice 2013 Book 9

153 Advice October 2013 ECOREGION STOCK Widely distributed and migratory stocks Leafscale gulper shark (Centrophorus squamosus) in the Northeast Atlantic Advice for 2014 The advice given in 2012 for this stock is biennial and valid for 2013 and 2014 (see ICES, 2012a): ICES advises on the basis of the precautionary approach that there should be no catches of leafscale gulper shark. The advice is summarized in the table below. Sources ICES. 2012a. Leafscale gulper shark (Centrophorus squamosus) in the Northeast Atlantic. In Report of the ICES Advisory Committee 2012, Section ICES Advice, Book 9: ICES. 2012b. Report of the Working Group on Elasmobranch Fishes (WGEF), June 2012, Lisbon, Portugal. ICES CM 2012/ACOM: pp. Table Leafscale gulper shark the Northeast Atlantic. ICES advice, management, and landings. Year ICES Advice 1 Predicted catch corresp. to advice 1 Agreed TAC for deepwater sharks ICES landings Zero catch No new advice, same as for TAC = 0, prevent bycatch No new advice, same as for Zero catch No new advice, same as for Zero catch No new advice, same as for Zero catch No new advice, same as for Weights in tonnes. 1 Advice prior to 2013 was for leafscale gulper shark and Portuguese dogfish combined. 2 Combined landings of leafscale gulper shark and Portuguese dogfish. ICES Advice 2013, Book 9 149

154 Advice June 2013 ECOREGION STOCK Widely distributed and migratory stocks Ling (Molva molva) in the Northeast Atlantic Advice for 2014 The advice given in 2012 for ling (Molva molva) assessment units is biennial and valid for 2013 and 2014 (see ICES, 2012). The advice is summarized in the table below. Sources ICES Ling (Molva molva) in the Northeast Atlantic. Report of the ICES Advisory Committee, ICES Advice, Book 9: Table Ling in the Northeast Atlantic. Summary of advice for different assessment units and landings. Year ICES advice ICES advice ICES advice ICES advice ICES Subareas I and II Division Va Division Vb All other areas 1 landings (Arctic) (Iceland) (Faroes) All areas % reduction on 30% reduction on 30% reduction on 30% reduction on 32.1 fishing effort 2 fishing effort 2 fishing effort 2 fishing effort Biennial 2 Biennial 2 Biennial 2 Biennial Effort reduced by 30% 2 Effort reduced by No increased in Effort reduced by % 2 effort 2 30% Biennial 2 Biennial 2 Biennial 2 Biennial Maintain catches below Maintain catches at No increased in Reduce about 30% 36.6 the recent (6) level (38) effort in catches (10) 2008 Biennial Biennial Biennial Biennial Constrain catches (6) Constrain catches to No increased in Constrain catches average (7.5) effort (10) 2010 Biennial Biennial Biennial Biennial Constrain catches to 8000 t Same advice as previously No increase in effort and a reduction in catches should be considered 2012 No new advice, same as % reduction in effort F proxy target 20% decrease in effort 2014 No new advice, same as 2013 Weights in thousand tonnes. 1 Divisions IIIa and IVa, and Subareas VI, VII, VIII, IX, XII, and XIV. 2 Advice for ling in Northeast Atlantic. Constrain catches to average, and a reduction in catches should be considered Reduce catches by 20% ICES Advice 2013 Book 9

155 Advice June 2013 ECOREGION STOCK Widely distributed and migratory stocks Blue ling (Molva dypterygia) in all areas in the Northeast Atlantic Advice for 2014 The advice given in 2012 for blue ling (Molva dypterygia) assessment units is biennial and valid for 2013 and 2014 (see ICES, 2012). The advice is summarized in the table below. Sources ICES Blue ling (Molva dypterygia) in all areas in the Northeast Atlantic. Report of the ICES Advisory Committee, ICES Advice, Book 9: Table Blue ling in the Northeast Atlantic. Summary of the advice for different assessment units and landings. Year ICES advice Division Va and Subarea XIV ICES advice Division Vb and Subareas VI and VII ICES advice Divisions IIIa and Iva, and Subareas I, II, VIII, IX, and XII ICES landings in all areas 2003 No direct fisheries 1 No direct fisheries 1 No direct fisheries Biennial Biennial Biennial No direct fisheries 1 No direct fisheries 1 No direct fisheries Biennial Biennial Biennial No direct fisheries No direct fisheries No direct fisheries Biennial Biennial Biennial No direct fisheries No direct fisheries No direct fisheries Biennial Biennial Biennial Same advice as previously Limit bycatches in mixed fisheries to current levels 2012 No new advice, same as 2011 No new advice, same as F proxy target (3 100 t) Average catch 2008 to 2011 (3 900t) No direct fisheries, and a reduction in catches should be considered No new advice, same as 2011 No direct fisheries, and a reduction in catches should be considered No new advice, same as No new advice, same as 2013 No new advice, same as 2013 Weights in thousand tonnes. 1 Advice for blue ling in the Northeast Atlantic (not split in different assessment units) ICES Advice 2013, Book 9 151

156 Advice October 2013 ECOREGION STOCK Advice for 2014 Widely distributed and migratory stocks Mackerel in the Northeast Atlantic (combined Southern, Western, and North Sea spawning components) ICES advises on the basis of the recent three years landings (see Quality considerations) that landings should be no more than t in Discards are known to take place, but cannot be quantified accurately; therefore total catches cannot be calculated. ICES advises that the existing measures to protect the North Sea spawning component should remain in place. Stock status Qualitative evaluation Qualitative evaluation F (Fishing Mortality) SSB (SpawningStock Biomass) Insufficient information Steady increase SSB index Figure Mackerel in the Northeast Atlantic. Landings in thousand tonnes (left) and SSB index from the triennial mackerel egg survey (right). Confidence intervals are currently not available for the egg survey index. In the catch plot the years prior to 2005 are shaded, indicating that the catch data are less certain in these years. Catches of mackerel have been increasing since 2005 and have been around 900 kt since The mackerel egg survey index show a doubling of the SSB since 2004, and a 30% increase from 2010 to 2013 (a preliminary value). Management plan A management plan was agreed by Norway, Faroe Islands, and the EU in October ICES has evaluated the plan and concluded that it is precautionary (ICES, 2008). However, since 2009, there has been no international agreement on TAC. The plan requires an agreed assessment which is currently not available for this stock. Biology The combined Northeast Atlantic (NEA) mackerel is assessed as one stock, but comprises three spawning components. Spawning areas of mackerel are widely spread, and only the North Sea component is sufficiently distinct to be clearly identified as a separate spawning component. Mackerel from the southern and western areas migrate to feed in the Nordic seas and the North Sea during the second half of the year, and then mix with the North Sea component. 152 ICES Advice 2013 Book 9

157 Environmental influence on the stock Catch and survey data from recent years indicate that the stock has expanded northwestwards during spawning and the summer feeding migration. This distributional change is likely a reflection of increased stock size coupled with changes in the physical environment and in the zooplankton concentration and distribution. The fisheries Traditionally, the fishing areas with higher catches of mackerel have been in the northern North Sea (along the border of Divisions IVa and IIa), around the Shetland Islands, and off the west coast of Scotland and Ireland. The southern fishery off Spain s northern coast has also accounted for significant catches. In recent years significant catches have also been taken in Icelandic and Faroese waters, areas where almost no catches were reported prior to In 2012, catches in this area constituted approximately half of the total reported landings. Catches from Greenland were reported for the first time in 2011, and have increased in In the Icelandic and Faroese fisheries, in the northwestern part of the distribution area, mackerel are caught together with herring. In the southern part of the distribution area, Atlantic mackerel (Scomber scombrus) can be caught together with Spanish mackerel (Scomber colias). Catches of both species are reported separately. Catch distribution Total catch (2012) = 893 kt, where ~98.3% are landings (pelagic trawls, purseseine nets, and handlines) and 1.7% discards (the latter is only available from a limited number of fleets and considered to be an underestimate). Effects of the fisheries on the ecosystem There is relatively little bycatch of nontarget species in the mackerel fishery, which tends to operate with pelagic trawl gear, purseseine nets, and handlines. Quality considerations This year ICES was requested to examine the effect of uncertainty in the catch. No specific guidance on the levels of uncertainty were given by the client, however a published study (Simmonds, 2010) had indicated that there was unaccounted mortality which could be explained by errors in reporting historical catches between factors of 1.6 and 3.6 times the reported catches. This range of uncertainty was chosen as the basis for a sensitivity analysis for unaccounted catches prior to This analysis showed that the assessment model used until 2012 would underestimate stock size if catches have been correctly reported since Overall the consideration of catch uncertainty was based both on this published evidence of unaccounted mortality and also on anecdotal evidence of the accuracy of the catch information from the fishing industry. This uncertainty was restricted to the period before After this date more effective catch reporting was instituted. Based on this sensitivity analysis and the perception of uncertainty in historical catches ICES concluded that potential catch for this stock had been underestimated in the recent past and that the previous stock assessment method was no longer an appropriate basis for providing catch advice for this stock. Continued use of this modelling approach would have given landings of approximately t. ICES also has available a triennial egg survey, which might be used as a relative index of spawning stock size, and combined with recent average landings to give advice under the ICES approach to datalimited stocks, DLS category 3.2. The 2013 surveys have only just been completed and only a preliminary point estimate of egg production and biomass is available. A final value for the 2013 survey and estimates of precision will be available in Until the necessary analyses are finalized it is not possible to use the survey in this DLS method because without information on precision it is not possible to determine whether the precautionary buffer should be applied or not. This index is unaffected by the uncertainty in the catch and has been used in the past as an index of SSB within the assessment model. The survey results, taken together with estimates of mortality based on catch, give strong indications that there has been an increase in stock size and that current levels of catch and landings do not pose a threat to the stock. Advice is based on landings from the three most recent years, but this advice is seen as an interim measure. ICES will attempt to incorporate more stock size information in an appropriate assessment model at the benchmark in Should this approach be unsuccessful a DLS approach will be developed based specifically on the triennial regime of survey data. Scientific basis Assessment No analytic assessment is available. Discards Discards have been included in the assessment since 1978, from Germany, Ireland, the Netherlands, Spain, and the UK. Discards cannot be quantified accurately and are regarded to be underestimated. Indicators None. Other information A benchmark is scheduled for ICES Advice 2013, Book 9 153

158 Working group report WGWIDE (ICES, 2013a). 154 ICES Advice 2013 Book 9

159 Supporting information October 2013 ECOREGION STOCK Widely distributed and migratory stocks Mackerel in the Northeast Atlantic (combined Southern, Western, and North Sea spawning components) Reference points Previous reference points are not cited here because the model basis for the assessment has been rejected. Outlook for 2014 No analytical assessment can be presented. The main cause is a change in the perception of the accuracy of the catch data prior to Sensitivity runs with alternative catch series demonstrated that the assessment model configuration was dependent on the accuracy of the historical catch data series. A benchmark assessment is scheduled for February 2014 which will consider alternative models as well as a suite of possible survey indices not currently used in the assessment. In the interim, considering that recent landings have been stable and that the stock appears to have increased, ICES considers that the current exploitation is appropriate in the short term. Therefore, ICES advises that catches should not increase in relation to the last three years average. This corresponds to landings of no more than t in Discards are known to take place, but cannot be quantified accurately; therefore total catches cannot be calculated. ICES approach to datalimited stocks For datalimited stocks for which a biomass index is available, ICES would normally use status quo landings adjusted by the survey index as a harvest control rule. This approach has not been used as the basis for the advice here because the survey is only conducted every third year and results from the most recent year (2013) are preliminary. Given that the survey results are preliminary and that mortality signals are equivocal, ICES is unable to determine if a precautionary buffer according to the datalimited approach should be applied (giving landings = t); however, ICES notes that advising an even larger increase in catch, as would be the case otherwise (giving landings = t), would not be precautionary. ICES is therefore unable to give advice based on the DLS approach and as an interim measure advises not to increase recent landings compared to the last three years (see above). Additional considerations Ecosystem considerations The changes in mackerel distribution and migration have been investigated in an Ad hoc Group on the Distribution and Migration of Northeast Atlantic Mackerel (AGDMM; ICES, 2013b). The accepted consensus of the AGDMM was that there has been an expansion of the distribution of spawning over time in the western component. This expansion has been geographically large, but is thought to contain a marginal proportion of total spawning. There has also been an expansion in the temporal distribution of spawning in the western and southern components to earlier in the year. The distribution of juvenile mackerel is very patchy, and abundance is highly variable between years. A northern expansion of the western component is indicated by the recent summer surveys in the Nordic Seas (IESSNS). Likewise a westward expansion in the summer distribution of adult mackerel has been observed in the Nordic Seas since 2007, as far west as southeast Greenlandic waters. The distribution of fish tends to be less patchy and more spread out during the summer feeding phase. There have also been physical changes in the environment with record high sea temperatures in recent years facilitating a large potential habitat for mackerel. Furthermore, the expansion could in part be due to a reduction in available food, requiring fish to spread out further to find adequate resources. Overwintering in Icelandic waters, never previously observed, occurred in 2010 and 2011 but not 2012, and in recent years (winter 2006/2007 and since 2009) the Faroe Plateau has been used as a nursery area for 0 and 1group mackerel. The question remains as to whether or not this expansion in distribution of mackerel is permanent or cyclical. Whatever the driving forces behind this are, it is likely to be a dynamic process, including interactions between several factors (stock size, temperature, zooplankton, oceanographic conditions, etc.). While the marginal distribution has changed notably, the spawning area has remained remarkably inert at its core. If oceanographic drivers are influential, then changes are likely to occur on the decadal scale, though the impact of climate change on these processes requires much further research. Likewise, if stock (size and structure) and prey (zooplankton) dynamics are important, then changes are unlikely to be permanent. ICES Advice 2013, Book 9 155

160 Management considerations The advice for 2014 results in advised landings of no more than tonnes; this is considerably higher than the TACs advised in recent years. The agebased assessment was rejected; therefore, the basis for advice is the average of the most recent three years landings. A discussion of the basis for the advice is given in Quality considerations. The fishery Mackerel is mainly exploited in a directed fishery for human consumption. This fishery tends to target bigger fish and there is evidence of discarding of smaller, less marketable fish. Regulations and their effects Prior to the late 1960s, spawning biomass of North Sea mackerel was estimated to be above 3 million tonnes. Subsequently, overexploitation occurred and recruitment has failed since 1969, leading to a marked decline in the size of the North Sea component. The measures advised by ICES have been aimed at protecting the North Sea spawning component and promoting stock recovery. Despite a small increase in the North Sea spawning up to 1999, the SSB has most recently declined again from 2005 to The closure of the mackerel fishery in Divisions IVb,c and IIIa throughout the whole year is designed to protect the North Sea component in this area, and also to protect juvenile Western mackerel which are numerous, particularly in Divisions IVb,c during the second half of the year. Unfortunately, the closure has resulted in increased discards of mackerel in the nondirected fisheries (especially horse mackerel fisheries) in these areas as vessels are currently permitted to take only 10% of their catch as mackerel bycatch. As estimates of mackerel bycatch are not available, the reported landings of mackerel in Divisions IIIa and IVb,c from 1997 and onwards underestimate catches because they do not include discarded bycatch. The advised fishery closure of Division IVa during the first half of the year is based on the perception that the Western mackerel enter the North Sea in July/August, and stay there until December before migrating back to their spawning areas. Observations in the late 1990s suggested that this return migration started in mid to late February. Since 2009, the return migration seems to occur earlier again. According to the EU TAC regulation some smaller quotas are assigned to Divisions IIIa and IVb,c. In the same regulation it is also stated that within the limits of the quota for the western component (Subareas and Divisions VI, VII, VIIIa,b,d,e, Vb (EU), IIa (noneu), XII, and XIV), a certain quantity of this stock may be caught in Division IVa, but only during the periods 1 January to 15 February and 1 September to 31 December. Existing measures to protect the North Sea spawning component are: There should be no fishing for mackerel in Divisions IIIa and IVb,c at any time of the year; There should be no fishing for mackerel in Division IVa during the period 15 February 31 July; The 30 cm minimum landing size at present in force in Subarea IV should be maintained. In the southern area a new Spanish national regulation affecting mackerel catches of Spanish fisheries has been implemented in 2010, distributing the Spanish catch quota by gear (30.5% quota for trawlers, 27.7% for purseseiners, and 34.6% for artisanal fisheries), halfyear, and area. Additionally, a stricter control on mackerel landings was enforced by the Spanish fishery administration. In 2011 the EU introduced a new regulation scheduling payback until 2015 due to overfishing of the mackerel quota allocated to Spain in 2010 (Commission Regulation (EU) No. 165/2011). A similar regulation applied to Scottish and Irish vessels expires in Other factors Stock components: ICES currently uses the term Mackerel in the Northeast Atlantic to define the mackerel present in the area extending from ICES Division IXa in the south to Division IIa in the north, including mackerel in the North Sea and Division IIIa. Catches cannot be allocated specifically to spawning area components on biological grounds, but by convention; catches from the Southern and Western components are separated according to the areas in which these are taken. To keep track of the development of spawning biomass in the different spawning areas, mackerel in the Northeast Atlantic stock are divided into three area components: the Western Spawning Component, the North Sea Spawning Component, and the Southern Spawning Component. 156 ICES Advice 2013 Book 9

161 Mackerel in the Northeast Atlantic Mainly distributed and fished in ICES Subareas and Divisions IIa, IIIa, IV, V, VI, VII, VIII, and IXa Spawning component Western Southern North Sea Main spawning areas VI, VII, VIIIa,b,d,e, VIIIc, IXa IV, IIIa The Western component is defined as mackerel spawning in the western area (ICES Divisions and Subareas VI, VII, and VIII a,b,d,e). This component currently accounts for ~75% of the entire Northeast Atlantic stock. Similarly, the Southern component (~22%) is defined as mackerel spawning in the southern area (ICES Divisions VIIIc and IXa). Although the North Sea component has been at an extremely low level since the early 1970s, ICES considers that the North Sea component still exists as a discrete unit (~3%). This component spawns in the North Sea and Skagerrak (ICES Subarea IV and Division IIIaN). Current knowledge of the state of the spawning components is summarized below. Western component: The catches of this component were low in the 1960s, but have increased since. The main catches are taken in directed fisheries by midwater trawlers and purseseiners. Large catches of the western component are taken in the northern North Sea, west of Scotland, and in the Nordic seas. A separate assessment for this stock component has not been conducted in recent years, as an extension of the timeseries of mackerel in the Northeast Atlantic data allows the estimation of the mean recruitment from 1972 onwards. Preliminary estimates of the SSB of the Western component derived from egg surveys indicate an increase from 3.43 million t in 2010 to 4.30 million t in North Sea component: Very large catches were taken in the late 1960s in the purseseine fishery, reaching a maximum of about 1 million tonnes in The component subsequently collapsed and catches declined to less than tonnes in the late 1970s. Annual catches in the last ten years are assumed to be about tonnes. Estimates of the SSB of the North Sea component derived from the North Sea egg survey indicate a decrease from 0.22 million t in 2005 to 0.17 million t in Southern component: Mackerel in this component are taken in a mixture of purseseine, demersal trawl, line, and gillnet fisheries. The highest catches (87%) from the Southern component are taken in the first half of the year, mainly from Division VIIIc, and consist of adult fish. In the second half of the year, the catches are mainly taken in Division IXa and contain a high proportion of juveniles. Catches from the Southern component increased from about t in the early 1990s to about tonnes in the early 2000s, reaching a peak at tonnes in 2009 and decreasing to tonnes in The 2011 decline was due to payback of tonnes and tighter regulations. Preliminary estimates of the SSB of the Southern component derived from egg surveys indicate an increase from 0.85 million tonnes in 2010 to 1.27 million tonnes in Data and methods The advice is partly based on the trend in SSB as reflected by the triennial mackerel egg survey estimates of SSB from 2007 to The SSB is estimated using the annual egg production method. The survey samples the density of mackerel eggs during six periods from January to July and is designed to cover the spawning distribution during each period. Samples of adult fish are also taken to estimate the fecundity of females. Additional information on data available is described in ICES (2013c). Information from the fishing industry Over the last five years the pelagic industry has encountered large shoals of mackerel over the entire distribution area which has expanded both south and north. This is not confined to one area or one fleet. Based on its qualitative information from the fishing grounds the industry is of the firm view that the abundance of mackerel has increased over the last number of years. The industry is also seeing signs of very good recruitment (above average) over the last number of years, particularly in 2009, 2010 and The industry believes that the ICES advice for 2014 is too conservative. The widespread distribution over the entire area creates problems with unwanted bycatches for some fleets targeting species other than mackerel. Stakeholders are actively seeking mechanisms that would allow inclusion of fishing industry information into the assessment process, and are involved in a number of pilot projects in this regard. Industry has scaled up its participation in the mackerel RFID tagging project; processing plants in Denmark, Iceland, Ireland and Scotland are now equipped to read mackerel tags, in addition to the existing tag reading facilities in Norway. ICES Advice 2013, Book 9 157

162 Comparison with previous assessment and advice ICES normally provides advice on mackerel in relation to the management plan. This year, however, ICES was unable to give advice in relation to the management plan as there was no accepted analytical assessment for mackerel in The assessment was not accepted because the perception it gave of the recent trends in biomass and development of fishing mortality were considered unreliable: the catch data prior to 2005 have been considered by ICES to be unreliable, but analyses carried out this year indicate that the effect of the unreliable historical catch is leading to increasing errors in the perception of the stock, more than had previously been perceived. The problems with the assessment could be addressed using an adapted or different assessment model and ICES has scheduled to undertake this work in In the absence of an analytical assessment and following the ICES protocol for giving advice, ICES provides an interim advice for 2014, based on average landings. In 2012 the advice was based on the management plan. Sources Burns, F., van Damme, C., Ulleweit, J., Fonn, M., Thorsen, A., and Franco, C Mackerel and Horse Mackerel Egg Survey. Preliminary Results. WD presented to WGWIDE, ICES EC request on evaluation of longterm management of the NEA mackerel stock and fishery. In Report of the ICES Advisory Committee, ICES Advice Book 9. Section ICES Report of the Working Group on Widely Distributed Stocks (WGWIDE), 28 August 3 September 2010, Vigo, Spain. ICES CM 2010/ACOM:12. ICES. 2011a. Report of the Working Group on Widely Distributed Stocks (WGWIDE), August 2011, ICES Headquarters, Copenhagen, Denmark. ICES CM 2011/ACOM:15. ICES. 2011b. Report of the Working Group on Mackerel and Horse Mackerel Egg Surveys (WGMEGS), April 2011, San Sebastian, Spain. ICES CM 2011/SSGESST: pp. ICES Report of the Working Group on Widely Distributed Stocks (WGWIDE), August 2012, Lowestoft, UK. ICES CM 2012/ACOM:16. ICES. 2013a. Report of the Working Group on Widely Distributed Stocks (WGWIDE), 27 August 02 September 2013, ICES Headquarters, Copenhagen, Denmark. ICES CM 2013/ACOM:15. ICES. 2013b. Report of the Ad hoc Group on the Distribution and Migration of Northeast Atlantic Mackerel (AGDMM). ICES CM 2013/ACOM: pp. 158 ICES Advice 2013 Book 9

163 Table Mackerel in the Northeast Atlantic. Advice, management, and catch data for the combined area. Year ICES Advice Predicted catch corresp. to advice Total agreed TAC 3 Official landings 5 Disc. 1 slip ICES catch 2, Given by stock component Given by stock component Given by stock component Given by stock component Given by stock component Given by stock component Given by stock component Given by stock component Given by stock component Significant reduction in F Significant reduction in F F between 0.15 and F of 0.15 consistent with PA n/a F=0.17: F pa F=0.17: F pa F=0.17: F pa F=0.17: F pa F=0.17: F pa F=0.15 to 0.20 [ ] F=0.15 to 0.20 [ ] F=0.15 to 0.20 [ ] F=0.15 to 0.20 [ ] F=0.15 to 0.20 [ ] harvest control rule [ ] See scenarios Follow the management plan [ ] Follow the management plan [ ] Recent landings (3years) < Weights in thousand tonnes. 1 Data on discards and slipping from only two fleets. 2 Landings and discards from Divisions and Subareas IIa, IIIa, IV, V, VI, VII, VIII, and IXa. 3 For all areas, except some catches in international waters in Subarea II. 4 Catches updated in 2003 with revisions from SGDRAMA in Updated with ICES FishStats data. 6 Incomplete. 7 Does not include the unilateral Norway/Faroe Islands TAC first declared in 2009, nor the Icelandic TAC. 8 No internationally agreed TAC for 2010, 2011, and Values presented are the sum of unilateral TACs. ICES Advice 2013, Book 9 159

164 Table Mackerel in the Northeast Atlantic. Advice, management, and catch data for the Western component. Year ICES Predicted catch Agreed Disc. ICES Advice corresp. to advice TAC 1 slip catch 2, SSB = 1.5 mill. t; TAC F = F 0.1; TAC; closed area; landing size Halt SSB decline; TAC TAC; F = F TAC; F = F TAC for both 1992 and TAC for both 1992 and No longterm gains in increased F % reduction in F No separate advice No separate advice No separate advice No separate advice No separate advice No separate advice No separate advice No separate advice No separate advice No separate advice No separate advice No separate advice No separate advice No separate advice No separate advice No separate advice No separate advice No separate advice No separate advice Weights in thousand tonnes. 1 TAC for mackerel taken in all Divisions and Subareas VI, VII, VIIIa,b,d, Vb, IIa, IIIa, and IVa. 2 Landings and discards of the Western component; includes some catches from the North Sea component. 3 Catch at status quo F. 4 Catches updated in 2003 with revisions from SGDRAMA in Revised from previous year (was 392). 6 No internationally agreed TAC. 160 ICES Advice 2013 Book 9

165 Table Mackerel in the Northeast Atlantic. Advice, management, and catch data for the North Sea component. Year ICES Advice Predicted catch corresp. to advice 1 Agreed TAC Lowest practical level LPL Closed areas and seasons; min. landing size; bycatch regulations LPL Closed areas and seasons; min. landing size; bycatch regulations LPL Closed areas and seasons; min. landing size; bycatch regulations LPL Closed areas and seasons; min. landing size; bycatch regulations LPL Closed areas and seasons; min. landing size; bycatch regulations LPL Maximum protection; closed areas and seasons; min landing size LPL Maximum protection; closed areas and seasons; min landing size LPL Maximum protection; closed areas and seasons; min landing size LPL Maximum protection; closed areas and seasons; min landing size LPL Maximum protection; closed areas and seasons; min landing size LPL Maximum protection; closed areas and seasons; min landing size LPL Maximum protection; closed areas and seasons; min landing size LPL Maximum protection; closed areas and seasons; min landing size LPL Maximum protection; closed areas and seasons; min landing size LPL Maximum protection; closed areas and seasons; min landing size LPL Maximum protection; closed areas and seasons; min landing size LPL Maximum protection; closed areas and seasons; min landing size LPL Maximum protection; closed areas and seasons; min landing size LPL Maximum protection; closed areas and seasons; min landing size LPL Maximum protection; closed areas and seasons; min landing size LPL Maximum protection; closed areas and seasons; min landing size LPL Maximum protection; closed areas and seasons; min landing size LPL Maximum protection; closed areas and seasons; min landing size LPL Maximum protection; closed areas and seasons; min landing size LPL Maximum protection; closed areas and seasons; min landing size LPL Maximum protection; closed areas and seasons; min landing size LPL Maximum protection; closed areas and seasons; min landing size LPL Weights in thousand tonnes. 1 Subarea IV and Division IIIa. 2 TAC for Subarea IV, Divisions IIIa, IIIb,c,d (EU zone), and Division IIa (EU zone). 3 Estimated landings of the North Sea component. 4 No information. LPL = Lowest Practical Level. ICES catch 3 ICES Advice 2013, Book 9 161

166 Table Mackerel in the Northeast Atlantic. Advice, management, and catch data for the Southern component. Year ICES Predicted catch corresp. Agreed ICES Advice to advice TAC 1 Catch Reduce juvenile exploitation Reduce juvenile exploitation No advice Reduce juvenile exploitation Reduce juvenile exploitation No advice No advice No advice No advice No separate advice No separate advice No separate advice No separate advice No separate advice No separate advice No separate advice No separate advice No separate advice No separate advice No separate advice No separate advice No separate advice No separate advice No separate advice No separate advice No separate advice No separate advice No separate advice Weights in thousand tonnes. 1 Division VIIIc, Subareas IX and X, and CECAF Division (EU waters only). 2 Catches updated in 2003 with revisions from SGDRAMA in ICES Advice 2013 Book 9

167 Table a Mackerel in the Northeast Atlantic (combined Southern, Western, and North Sea spawning components). Catches (in tonnes) by country (data submitted by Working Group members). Country Belgium Denmark Estonia Faroe Islands France Germany, Fed. Rep Germany, Dem. Rep Guernsey Iceland Ireland Jersey Latvia Lithuania 2085 Netherlands Norway Poland Portugal Romania 2903 Spain Sweden United Kingdom Russia/USSR Misreported Unallocated Discards Total ICES Advice 2013, Book 9 163

168 Table b Mackerel in the Northeast Atlantic (combined Southern, Western, and North Sea spawning components). Catches (in tonnes) by country (cont.) (data submitted by Working Group members). Country Belgium Denmark Estonia Faroe Islands France Germany, Fed. Rep Germany, Dem. Rep. Greenland Guernsey Iceland Ireland Jersey Latvia Lithuania Netherlands Norway Poland Portugal Romania Spain Sweden United Kingdom Russia/USSR (Russia from 1990) Misreported Unallocated Discards Total ICES Advice 2013 Book 9

169 Table a Mackerel in the Northeast Atlantic (combined Southern, Western, and North Sea spawning components). Catches by area. Discards not estimated prior to 1978 (data submitted by Working Group members). YEAR SUBAREA VI SUBAREA VII AND DIVISIONS VIIIABDE SUBAREAS III AND IV SUBAREAS I,II,V AND XIV DIVISIONS VIIIC AND IXA TOTAL Ldg Disc Catch Ldg Disc Catch Ldg Disc Catch Ldg Disc Catch Ldg Disc Catch Ldg Disc Catch ,800 4,800 47,404 47, , , ,526 42, , , ,900 3,900 72,822 72, , , ,172 70, , , ,200 10,200 89,745 89, , , ,942 32, , , ,000 13, , , , , ,262 29, , , ,200 52, , , , ,519 21,600 21,600 25,967 25, , , ,100 64, , , , ,391 6,800 6,800 30,630 30, , , ,800 64, , , , ,062 34,700 34,700 25,457 25, , , ,800 67, , , , ,709 10,500 10,500 23,306 23, , , ,800 74, , , , ,531 1,400 1,400 25,416 25, , , ,700 15, , ,500 35, , , ,817 4,200 4,200 25,909 25, ,126 50, , ,300 20, , ,000 39, , , ,823 7,000 7,000 21,932 21, ,555 60, , ,700 6, , ,100 15, ,700 87,931 87,931 8,300 8,300 12,280 12, ,311 21, , ,100 2, , ,300 39, ,100 64,172 3,216 67,388 18,700 18,700 16,688 16, ,960 45, , ,400 4, , ,800 20, ,600 35, ,483 37,600 37,600 21,076 21, ,909 25, , ,500 2, , ,000 9, ,000 40, ,985 49,000 49,000 14,853 14, ,242 11, , ,100 1, , ,400 10, ,900 43, ,898 98,222 98,222 20,208 20, ,626 12, , ,140 2, ,875 75,043 1,800 76,843 46,790 3,656 50,446 78,000 78,000 18,111 18, ,084 8, , , , , , ,309 7, , , ,000 24,789 24, ,697 7, , , , , , ,829 10, ,618 47,000 47,000 22,187 22, ,016 10, , ,600 3, ,700 75,600 2,700 78, ,550 29, , , ,404 24,772 24, ,926 35, , ,300 2, ,900 72,900 2,300 75, ,410 2, ,600 90,488 90,488 18,321 18, ,419 7, , ,800 5, ,600 56,300 5,500 61, ,800 4, , , ,700 21,311 21, ,911 15, ,511 ICES Advice 2013, Book 9 165

170 Table b Mackerel in the Northeast Atlantic (combined Southern, Western, and North Sea spawning components). Catches by area (cont.). Discards not estimated prior to 1978 (data submitted by Working Group members). YEAR SUBAREA VI SUBAREA VII AND SUBAREAS III SUBAREAS I,II,V DIVISIONS VIIIC TOTAL DIVISIONS VIIIABDE AND IV AND XIV AND IXA Ldg Disc Catch Ldg Disc Catch Ldg Disc Catch Ldg Disc Catch Ldg Disc Catch Ldg Disc Catch ,500 10, ,200 50,500 12,800 63, ,700 7, ,900 97,800 97,800 20,683 20, ,183 30, , ,906 9, ,526 72,153 12,400 84, ,184 2, , , ,062 18,046 18, ,351 25, , ,497 2, ,167 99,828 12, , ,838 2, , , ,973 19,720 19, ,856 18, , ,338 1, , ,088 2, , ,247 1, ,397 72,309 72,309 25,043 25, ,025 5, , , , ,883 6, , , , , ,496 27,600 27, ,079 7, , , ,150 73,351 9,773 83, ,451 1, , , ,376 34,123 34, ,196 11, , ,044 2,240 67, ,719 13, , ,680 2, , , ,598 40,708 40, ,749 18, , , ,181 3, , ,947 4, , , ,219 44,164 44, ,652 8, , , ,362 94,290 94, , ,014 72,848 72,848 43,796 43, , , , , ,566 1, , , ,898 92,557 92,557 36,074 36, ,524 2, , , , ,890 1, , , ,971 67,097 67,097 43,198 43, ,274 1, , ,847 12, , ,484 2, , ,708 8, ,878 73,929 73,929 49,576 49, ,131 23, , , ,819 89,492 89, ,639 9, ,766 53,701 53,701 25,823 25, ,119 9, , , ,491 99,922 1, , ,768 8, ,620 62,486 62,486 34,840 34, ,248 10, , ,960 11,400 91,361 90,278 5,878 96, ,740 2, ,223 54,129 54,129 49,618 49, ,726 19, , ,077 6,031 94,108 66,209 6,556 72, ,929 5, ,312 46,716 46,716 52,751 52, ,682 17, , , ,193 71,235 2,024 73, ,013 6, ,200 72,891 72,891 62,834 62, ,761 8, , ,358 21,793 98,151 73,377 1,987 75, ,251 2, , , ,669 59,859 59, ,297 26, , ,468 1, ,723 88,287 4,387 92, ,928 7, , , , , , ,034 12, , , , ,127 3, , , , , ,729 49,068 3,126 52, ,470 6, , ,756 1, ,389 50,699 6,027 56, , , , ,761 18, , ,807 9, , , ,141 65,720 10,965 76, , , , ,207 24,940 3,849 28, ,382 15, , ICES Advice 2013 Book 9

171 Table Mackerel in the Northeast Atlantic (combined Southern, Western, and North Sea spawning components). Estimated catches for Estimation of 2013 catch Tonnes Reference EU quota and Swedish quota 338,392 European Council Regulation 2013/297 UKIreland payback 0 European Council Regulation 2012/147 Spanish payback 8,126 European Council Regulation 2012/976 Other EU payback 6 tadeductionsfor2013.pdf Norwegian quota 153,597 European Council Regulation 2013/297 Russian quota 68,359 WGWIDE estimate Discards 15,380 Previous years estimate Icelandic quota 123,182 Interannual quota transfer 2012>2013 2,827 WGWIDE estimate Ministry of Industries and Innovation: Press release 2 Feb Faroese quota 125,852 Ministry of Fisheries: Press release 26 Mar 2013 Interannual quota transfer 2012> ,000 Ministry of Fisheries: Press release 26 Mar 2013 Greenland expected catch 50,044 WGWIDE estimate Expected overcatch 6,165 Based on 2012 overcatch percentage Total expected catch (incl. discard) 895,336 ICES Advice 2013, Book 9 167

172 Figure Northeast Atlantic mackerel. Commercial catches in 2012, quarters ICES Advice 2013 Book 9