Predicted catch for 2016, per stock and scenario overshoot (hatched) and undershoot (below zero)

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1 ICES Advice on fishing opportunities, catch, and effort Celtic Seas Ecoregion Published 30 June Mixed-fisheries advice for Divisions VIIb,c,e k (Celtic Sea) Scenarios for 2016 Mixed-fisheries considerations are based on the single-stock assessments, combined with knowledge of the species composition in catches in the Celtic Sea demersal fisheries. Six example scenarios of fishing opportunities considering mixed fisheries are presented, taking into account the single-stock advice for fisheries catching cod, haddock, and whiting. Without specific mixed-fisheries management objectives, ICES cannot recommend specific scenario(s). Predicted catch for 2016, per stock and scenario overshoot (hatched) and undershoot (below zero) Max Min Cod Haddock Whiting Status quo effort Single-stock advice 2016 Whiting whiting Predicted catches 2016 haddock Haddock Cod cod Figure Mixed-fisheries advice in the Celtic Sea. Celtic Sea mixed-fisheries projections. Estimates of potential catches (in tonnes) by stock and by scenario. Horizontal lines correspond to the single-stock catch advice for Bars below the value of zero show undershoot (compared to single-stock advice) where catches are predicted to be lower when applying the scenario. Hatched columns represent catches that overshoot the single-stock advice. ICES Advice 2015, Book 6 1

2 Published Day Month 2015 Advice on fishing opportunities, catch, and effort Table Mixed-fisheries scenarios considered for the Celtic Sea gadoids. Scenarios Abbreviation Explanation Maximum max For each fleet, fishing stops when all stocks have been caught up to the fleet s stock shares*. This option causes overfishing of the single-stock advice possibilities of most stocks. Minimum min For each fleet, fishing stops when the catch for any one of the stocks meets the fleet s stock share. This option is the most precautionary option, causing underutilization of the single-stock advice possibilities of other stocks. Cod MSY All fleets set their effort corresponding to that required to catch their cod stock share, regardless cod approach of other catches. Haddock MSY All fleets set their effort corresponding to that required to catch their haddock stock share, had approach regardless of other catches. Whiting MSY All fleets set their effort corresponding to that required to catch their whiting stock share, whg approach regardless of other catches. status quo effort Sq_E The effort of each fleet is set equal to the effort in the most recently recorded year for which catch and effort data are available. *Throughout this document, the term fleet s stock share or stock share is used to describe the share of the fishing opportunities for each particular fleet, which has been calculated based on the single-stock advice for 2016 and the historical proportion of the stock landings taken by the fleet. The fisheries Fleet and métier categories used in the mixed-fisheries analysis are based on the EU data collection framework (DCF) level 5 categories, but merging over DCF categories has been performed to aggregate over small métiers (a métier failing to land at least 1.0% in 2014 of at least one of the stocks considered). Catch distribution Table Mixed-fisheries advice In the Celtic Sea. Catch distribution. Total landings (2014) of all species considered in the mixedfisheries advice were t, with: ~ 86% landed by otter trawls and seines; ~ 3% by beam trawls; ~ 2% by gill- and trammel nets; and ~ 9% by other gears. Total discards were 7635 t (23% by weight of total catch). Cod discards are not included in the analysis. Quality considerations Mixed-fisheries projections for the Celtic Sea build on full analytical single-stock assessments. Single-stock forecasts are also reproduced independently as part of the mixed-fisheries analyses, allowing additional quality control of both processes. The quality of data on catch, disaggregated by métier, has improved in recent years because of the single ICES data call combining data needs and ensuring common data storage in Intercatch for single-stock assessment and mixed-fisheries forecasts. 2 ICES Advice 2015, Book 6

3 ICES Advice on fishing opportunities, catch, and effort Published Day Month 2015 To maintain consistency with the single-stock advice, the mixed-fisheries analysis is based on total catch (landings and discards) for haddock and whiting, but only on landings for cod. The mixed-fisheries analysis assumes fishing effort in 2015 (intermediate year) is the same as in This results in fishing mortality and catch that differs from the single-stock advice (which assumes an average F( ) for 2015). Consequently, catch in 2016 consistent with the MSY approach also differs slightly. Catch options Mixed-fisheries advice considers the implications of mixed fisheries operating under single-stock TAC limits, taking into account the fishing pattern and catchability of the various fleets in The scenarios therefore do not assume any amount of quota balancing through adaptation of fishing behaviour. The advice is presented in terms of catch under different scenarios. The min scenario is based on the assumption of a strictly implemented discard ban. In the min scenario, the most limiting stocks are cod, haddock, and whiting for fishing activities that represent 83%, 12%, and 5% of the effort (kw-days) in 2014, respectively. In the max scenario, the least limiting stocks are whiting, cod, and haddock for fishing activities that represent 92%, 6%, and 2% of the effort (kw-days) in 2014, respectively. The max and Sq_E scenarios result in cod being fished above the precautionary level (Fpa) in 2016, which is therefore not considered precautionary (Table ). None of the scenarios results in SSB in 2017 falling below the precautionary level (Bpa) for any of the stocks (Table ). The ICES single-stock advice for demersal stocks (ICES, 2015a) is based on the ICES maximum sustainable yield (MSY) approach. All scenarios except min and cod result in cod being fished above FMSY, while all the scenarios except min, cod, and had result in haddock being fished above FMSY. Whiting is fished at or below FMSY in 2016 in all scenarios except max, reflecting that whiting is the least limiting stock for most fleets. Table Mixed-fisheries advice in the Celtic Seas Ecoregion. Catch options for 2016 for single-stock advice and mixed-fisheries scenarios. Weights in thousand tonnes. Basis: single-stock assessments up to The status quo effort scenario (Sq_E) is assumed to take place in Fishing patterns and catchability in 2015 and 2016 were assumed to remain as in Stock Single-stock catches Catches per mixed-fisheries scenario 2016 advice 2016 "max" "min" cod had whg "Sq_E" Cod VIIe k Haddock VIIb k Whiting VIIb,c,e k Mixed-fisheries catch options can take specific management priorities into account. Scenario results show that it is not possible to achieve all management objectives simultaneously. For instance, if FMSY for all stocks is the objective, this means that the whiting and haddock TACs at FMSY cannot be fully utilized in the mixed gadoid fisheries. In contrast to single-stock advice there is no single recommendation, but a range of plausible options. ICES single-stock advice provides TACs expected to meet single-stock FMSY. To be consistent with these objectives a scenario is necessary that delivers the SSB and/or F objectives of the single-stock advice for all stocks considered simultaneously. This document presents six example scenarios of which only the min scenario meets the objective of all stocks being fished at or below FMSY. However, for most fleets this implies effort levels that are halved compared to the levels observed in In addition to the min scenario a max scenario is included. The latter scenario demonstrates the upper bound of potential fleet effort and stock catches in that it assumes that all fleets continue fishing until all their stock shares are exhausted, irrespective of the economic viability of such actions. The Sq_E scenario is very similar to the max scenario. The max scenario suggests that if all fleets stock shares are to be fully utilized, catches of cod and haddock would be considerably higher than advised in the single-stock advice. Conversely, reductions in fishing effort or significant changes to exploitation patterns are required to avoid overexploiting cod and haddock if all fleets catch their whiting stock shares in full. ICES Advice 2015, Book 6 3

4 Published Day Month 2015 Advice on fishing opportunities, catch, and effort Issues relevant for the advice Management considerations There are no specific management plans in place for cod, haddock, or whiting in the Celtic Sea. Mixed-fishery scenarios are based on central assumptions that fishing patterns and catchability in 2015 and 2016 are the same as those in 2014 (similar to procedures in single-stock forecasts where growth and selectivity are assumed constant). The scenarios therefore do not assume any amount of quota balancing through adaptation of fishing behaviour. Scenarios that result in under- or overutilization are useful in identifying the main points of friction between the fishing opportunities of the various stocks. They indicate in which direction fleets may have to adapt to fully utilize their catch opportunities. Under the scenarios presented here, a change to the exploitation pattern for cod and haddock (i.e. a reduction in catches relative to whiting) will be required in 2016 to avoid overexploitation of these stocks, or underexploitation of whiting. The min scenario corresponds to a strictly implemented discard ban for all three stocks considered. The analysis highlights where fleets with a small share but high discard rate for a stock have their fishing activity limited by that stock, resulting in underutilization of their target stock(s). This can translate to underutilization at the national level, as seen by the change in landings share of the stocks by EU Member States in the mixed fisheries forecasts. Supporting measures aimed at minimizing the misalignment between activity and stock shares for the fleets, such as changes in gear selectivity, spatio-temporal management measures, or re-allocation of stock shares, will be required if fishing opportunities are to be fully taken under a discard ban. A series of technical measures are in place for demersal trawl gears operating in various parts of the Celtic Sea. This includes maximum number of meshes in circumference and minimum mesh size, depending on the target composition and/or area. More recently square mesh panels (SMP) were introduced. The aims of these technical measures is to change catchability by improved selection within the Celtic Sea fisheries, reducing catches of small whiting and haddock. Depending on the efficacy of the measures as implemented in practice there will be short-term changes in catchability which are assumed to be fixed in the mixed-fisheries forecast. The conclusion that cod is the most limiting species in the Celtic Sea mixed fisheries is robust to this because the SMP measures are least effective for cod. Since 2005, three ICES rectangles (30E4, 31E4, and 32E3) have been closed during the first quarter (known as the Trevose closure Council Regulations 27/2005, 51/2006, 41/2007, 40/2008, and 43/2009) with the objective of reducing fishing mortality on cod. STECF (2007) concluded that the closure is a potentially effective measure for displacing fishing activities away from spawning aggregations off North Cornwall and hence making vessels less efficient at catching cod. The major impact of the closure appears to have been on French trawlers that historically have taken a large proportion of the cod landings in Divisions VIIe k. The effectiveness of the closed rectangle off the Irish coast is less evident, due to its lesser importance as a fishing ground for the EU whitefish fleets and the poorer knowledge of the distribution of cod spawning activity off the southeast coast of Ireland. The quantitative impact of this closure was evaluated by ICES in 2007 in response to a special request from the EC and it could not be quantitatively disentangled from other factors (ICES, 2007). Catch and landing advice The mixed-fisheries projections are presented in terms of catch. Total catch is forecast based on current selection patterns observed in the fisheries (in 2014), except for cod where discards are uncertain and so only landings are presented. Species involved This mixed-fisheries forecast is limited to three gadoid stocks with full analytical single-species assessments. Further work is ongoing to include additional analytical stocks (e.g. the Nephrops stocks). Methods to include stocks without analytical assessments in the mixed-fisheries forecasts based on catch per unit effort are also being developed in order to take account of the potential choke species for fleets operating under a landing obligation. 4 ICES Advice 2015, Book 6

5 ICES Advice on fishing opportunities, catch, and effort Published Day Month 2015 Plaice and sole were also considered for inclusion but are thought to have limited technical interaction with the gadoid stocks (ICES, 2015e). Table Mixed-fisheries advice In the Celtic Sea. Advice and management area for the three gadoids species considered. Species ICES single-stock advice area Management area Cod Divisions VIIe k EU TAC Divisions VIIb, VIIc, and VIIe k and Subareas VIII, IX, and X; EU waters of CECAF Haddock Divisions VIIb k EU TAC Divisions VIIb k and Subareas VIII, IX, and X; EU waters of CECAF Whiting Division VIIb,c,e k EU TAC Divisions VIIb, VIIc, VIId, VIIe, VIIf, VIIg, VIIh, VIIj, and VIIk Data and methods The projections made use of data requested as part of an ICES data call issued formally under the EU Data Collection Framework (DCF) regulations. This provides a much greater consistency between catch totals supplied to ICES. To allow consideration of fleets defined by length categories, separate data files containing total weight of landings and discards and effort in kw-days by fleet and métier were also requested. All analyses were conducted using the Fcube method (Ulrich et al., 2011). Uncertainties in the assessment The quality of the individual forecasts of the single stocks may affect the results of the mixed-fish scenarios. An error or bias in the forecast of one stock could lead to an inappropriately low or high TAC for this stock. This in turn would affect the estimated effort required for each métier to land this TAC. If the effort required to land the TAC for this stock is pivotal in any of the scenarios examined, this would affect the exploitation prognoses of the other stocks in this scenario. In other words, the quality of the mixed-fish model is limited by the stock which has the most biased assessment, if that stock is the limiting factor in a mixed-fisheries scenario. A key assumption in the forecast is that catchability for fleets remains constant, but this is heavily dependent on fishing patterns, which may change over time particularly in response to significant changes in policy, such as the introduction of a landing obligation. Another assumption is that the selectivity is the same for all fleets (based on the F-at-age derived from the assessment). Therefore, changes in the relative contribution of each fleet to the total effort cannot be translated into specific changes in the relative F-at-age. This prevents the use of better selection patterns for some fleets (such as gillnetters) in achieving the MSY approach. The possibility of using catch-at-age by fleet through the Intercatch database is being investigated. Comparison of the basis of previous assessment and advice This is the first year the Celtic Sea mixed-fisheries assessment and advice has been produced. The basis for the advice is presented through a series of mixed-fisheries scenarios which illustrate the consequences of single-species advice when catches are taken as part of a mixed gadoid fishery. Reference points The reference points for the various stocks can be found in the single-stock advice sheets (ICES, 2015b, 2015c, 2015d). Basis of the assessment ICES Advice 2015, Book 6 5

6 Published Day Month 2015 Advice on fishing opportunities, catch, and effort Table Mixed-fisheries advice In the Celtic Sea. The basis of the assessment. ICES stock data category 1 (ICES, 2015a). Assessment type Fcube (FLR). Input data Assessments on the relevant stocks in the Celtic Sea Ecoregion fisheries working group (WGCSE), catch and effort by fleet and métiers. Discards and bycatch Included as in the single-stock assessments where possible. Indicators None. Other information This assessment was presented for the first time in 2014 at the MIXFISH-METHODS (ICES, 2015e). As any scenario results in trade-offs between different fisheries that are informed by more than scientific considerations, no one scenario is presented as advice. The scenarios indicate which stocks will limit, and thus influence, the fisheries most. Working group report Working Group on the Assessment of Demersal Stocks in the Celtic Sea Ecoregion (WGCSE); Working Group on Mixed Fisheries Advice (WGMIXFISH-ADVICE). Information from stakeholders There is no available information. 6 ICES Advice 2015, Book 6

7 ICES Advice on fishing opportunities, catch, and effort Published Day Month 2015 Summary of the assessment Figure Mixed-fisheries advice in the Celtic Sea. Estimates of potential SSB at the start of 2017 by stock after applying the mixedfisheries scenarios, expressed as a ratio to the single-stock advice forecast. The horizontal line indicates the SSB resulting from the single-stock advice (at the start of 2017). ICES Advice 2015, Book 6 7

8 Published Day Month 2015 Advice on fishing opportunities, catch, and effort Figure Mixed-fisheries advice in the Celtic Sea (ICES Divisions VIIb,c,e k). Landings distribution of species by métier with landings consisting of 1% of any of the stocks (see Table ) in 2014 (list of métiers available in Table ). Note: The other (OTH) displayed here is a mixed category consisting of (i) landings without corresponding effort and (ii) landings of any combination of fleet and métier with landings < 1% of any of the stocks 1 3 in Table Mixed-fisheries advice in the Celtic Sea. TAC year (2016) fishing mortality forecast by scenario. The F range is averaged across the same ages as those used for the single-stock assessment. Stock Single-stock F Basis for the F per mixed-fisheries scenario in 2016 advice 2016 advice "max" "min" cod had whg "Sq_E" Cod VIIe k 0.31 MSY approach Haddock VIIb k 0.4 MSY approach Whiting VIIb,c,e k 0.32 MSY approach ICES Advice 2015, Book 6

9 ICES Advice on fishing opportunities, catch, and effort Published Day Month 2015 Table Mixed-fisheries advice in the Celtic Sea. SSB results from single-stock advice and different mixed-fisheries scenarios (see Figure ). Weights in thousand tonnes. Stock Single-stock SSB (2017) resulting from mixed-fisheries scenario applied in 2016 advice SSB results in "max" "min" cod had whg "Sq_E" 2017 Cod VIIe k Haddock VIIb k Whiting VIIb,c,e k legend SSB 2017 > B pa or MSY B trigger SSB 2017 > B lim, no B pa defined SSB 2017 > B lim SSB 2017 < B lim Table Mixed-fisheries advice In the Celtic Sea. Métier categories used in the mixed-fisheries analysis. Mixed-fisheries métiers Gear Target species OTB_DEF Otter trawls Demersal fish OTT_DEF Twin otter trawls Demersal fish SSC_DEF Scottish seines Demersal fish GNS_DEF Gillnets Demersal fish GTR_DEF Trammelnets Demersal fish TBB_DEF Beam trawls Demersal fish OTB_CRU Otter trawls Crustaceans OTT_CRU Twin otter trawls Crustaceans LLS_FIF Longlines Finfish MIS_MIS / OTH Other gears Any Sources and references ICES Report of the Working Group on the Assessment of Southern Shelf Demersal Stocks (WGSSDS). Annex 2: Effect on fishing activity on the 2007 Celtic Sea (30E4, 31E4 and 32E3) closure. 26 June 5 July ICES CM 2007/ACOM:28. ICES. 2015a. Advice basis. In Report of the ICES Advisory Committee, ICES Advice 2015, Book 1. In preparation. ICES. 2015b. Cod (Gadus morhua) in Divisions VIIe k (Eastern English Channel and Southern Celtic Seas). In Report of the ICES Advisory Committee, ICES Advice 2015, Book 5, Section ICES. 2015c. Haddock (Melanogrammus aeglefinus) in Divisions VIIb k (Southern Celtic Seas and English Channel). In Report of the ICES Advisory Committee, ICES Advice 2015, Book 5, Section ICES. 2015d. Whiting (Merlangius merlangus) in Divisions VIIb,c,e k (Southern Celtic seas and Eastern English Channel). In Report of the ICES Advisory Committee, ICES Advice 2015, Book 5, Section ICES. 2015e. Report of the Working Group on Mixed Fisheries Methods (WGMIXFISH-METH). ICES CM 2014/ACOM:75. STECF Evaluation of closed area schemes (SGMOS-07-03). Subgroup on management of stocks (SGMOS), of the Scientific, Technical and Economic Committee for Fisheries (STECF). Ulrich, C., Reeves, S. A., Vermard, Y., Holmes, S., and Vanhee, W Reconciling single-species TACs in the North Sea demersal fisheries using the Fcube mixed-fisheries advice framework. ICES Journal of Marine Science, 68: ICES Advice 2015, Book 6 9