COMMISSION OF THE EUROPEAN COMMUNITIES &200,66,2167$)):25.,1*3$3(5. Vigo January 2001

Transcription

1 COMMISSION OF THE EUROPEAN COMMUNITIES Brussels, SEC(2001) 1193 &200,66,2167$)):25.,1*3$3(5 5HSRUWRIWKH:RUNLQJ*URXSRQWKHSUHSDUDWLRQRIIXWXUHUHFRYHU\PHDVXUHVIRU 1RUWKHUQ+DNH Vigo January 2001

2 7$%/(2)&217(176 (;(&87,9(6800$5<,1752'8&7, BACKGROUND TO THE MEETING $.(-89(1,/($1'$'8/7',675,%87, INFORMATION ON JUVENILE HAKE DISTRIBUTIONS COMING FROM SCIENTIFIC BOTTOM TRAWL SURVEYS DISTRIBUTION OF ADULT HAKE FROM EGG AND LARVAE SURVEYS... 4 ),6+(5<81,76,1,&(668%$5($6,99,9,,$1'9,,,:+,&+&$7&++$.( 4.1 OVERVIEW FISHERY UNITS ON NORTHERN HAKE RUWKHUQ+DNHFRPSRVLWLRQVE\)LVKHU\8QLWDQG6XEDUHD 4.3 FLEET DESCRIPTIONS 'HQPDUN)OHHWV 6SDQLVKIOHHWV Trawl fleet Longline fleet Gill nets IOHHWV Sub-areas IV and VI, North Sea and West of Scotland Otter-trawl, roundfish Otter-trawl, Angler and Megrim Otter trawl, Nephrops Division VIIa, Irish Sea Nephrops trawl Whitefish Otter trawl Semi-pelagic trawls Longline Division VIIe, Western Channel Otter trawl Beam Trawl Static gear Divisions VII f-k, Celtic Sea Otter trawl Beam Trawl Static gear...14,ulvkiohhwv Irish fleet activity...15 )UHQFKIOHHWV $5(9,(:2)7+($66(660(172)7+(1257+(51+$.(672&.35(3$5('%<7+(,&(66287+(516+(/)'(0(56$/:*,16(37(0%(5 5.1 SUGGESTED IMPROVEMENTS FOR THE ASSESSMENT (3$5$7,212)7+(1257+(51+$.(672&.$66(660(17,17221()25$5($ 9,,,',9,6,2169,,,$%'($1'21() ) 1 672&.$1'5(&58,70(175(/$7,216+,3$1'%,2/2*,&$/5()(5(1&(32,176 ',6$**5(*$7,212)7+($66(660(17'$7$,172)/((76250e7,(56:,7+ :+,&+723(5)2506,08/$7,21678',(62)7+(())(&762)7(&+1,&$/0($685(6 $,0('$73527(&7,1*-89(1,/(+$.( 8.1 DISCARD DATA $6&+('8/(2)02'(//,1*:25.,1&/8',1*$5(9,(:2)7+(%,2/2*,&$/ 5()(5(1&(32,17672%(&203/(7(')257+(67(&)3/(1$5<0((7,1*7+ $35,/ 3266,%/(5(6($5&+$5($672%(,1&/8'(',1$+$.(672&.5(&29(5<3/$ SPAWNING AREAS... 27

3 10.2 NURSERY AREAS BIOLOGICAL PARAMETERS AGE ESTIMATION DISCARDS TECHNICAL CONSERVATION MEASURES SIMULATION WORK STOCK STRUCTURE ECONOMICS THE FISHERY ASSESSMENTS ()(5(1&(6 $33(1',;,««+$.(-89(1,/(6$1'$'8/76',675,%87,21««««««««««$ $33(1',;,,«',675,%87,212)&$7&+(6%<1$7,21$/)/((76««««««««$ $33(1',;,,,«&203$5$7,9($66(660(177$%/(6«««««««««««««««$ $''(1'80«)5(1&+/$1',1*62)+$.($1')/((76*($56,192/9('«$''(1'80

4 ([HFXWLYHVXPPDU\ In answer to the terms of reference for this meeting: 1. The assessment of the northern hake stock prepared by the ICES Southern Shelf Demersal WG in September 2000 was reviewed and a comparative assessment was carried out using additional catch and survey data not used by the WG, paying special attention to three issues, namely: 1. the low recruitments indicated for the 3 recent year classes ; 2. the abrupt rise in F, and concomitant sharp decrease in SSB, from 1998 to 1999; 3. the low catches predicted for 2000 under status quo F. The comparative assessment showed no significant difference in the stock status and recruitment pattern used by ICES/ACFM to give advice in November The Group considers that, at this stage, there is no advantage in reviewing the biological reference points for this stock. 2. In view of the impossibility to segregate the assessment data for northern hake prior to 1994, for catches taken in the Bay of Biscay and in areas to the north, and because a common age-length key is used to derive the catch-at-age matrix, the Group was unable to carry out indicative assessments for those parts of the hake population exploited to the south and north 48 N. However, the catch-at-age data used in the ICES assessment were disaggregated into fleet unit components and these are now available to perform simulation studies of the effects of technical measures aimed at protecting juvenile hake and harvesting rules to fix the TACs. 3. Possible research areas aimed at improving knowledge of the hake and its fishery were discussed in relation to their importance to a stock recovery plan, and with respect to the availability of results for input to Emergency Measures, the Recovery Plan or longer term topics that could be used to adjust the Recovery Plan and improve assessments (see Section 10). 4. A schedule of modeling work required to advise the Hake Recovery Plan has been agreed and is presented at Section 9. The work relates to two phases; the recovery phase, for which it will be necessary to carry out deterministic simulations with annual predictions and various recruitment levels, and the post-recovery phase, for which a stochastic stock/recruitment relationship should be used and giving an output of statistical averages. 5. This report has been completed to inform a regional workshop to be held in Brussels by the Commission on 24 th January A Report on the additional simulation work will be completed for the STECF plenary meeting 2-6th April

5 ,QWURGXFWLRQ As part of the development of the recovery plans for the Northern stock of Hake, a working group met at the IEO Laboratory, Vigo, on th January The WG members were:,1'(3(1'(17(;3(576 Alain Biseau Lisa Borges Enrique de Cardenas Paul Connolly Paulino Lucio Benoit Mesnil Sten Munch-Petersen Mike Pawson (France) (Ireland) (Spain) (Ireland) (Spain) (France) (Denmark) (UK, chair) Carmela Porteiro (Spain) Mike Smith (UK) Valentin Trujillo (Spain) (8523($1&200,66,21 Alain Laurec Franco Biagi (EC) (EC) %DFNJURXQGWRWKHPHHWLQJ Regional workshops arranged by the Commission in 2000 identified the imminent collapse of the Northern Hake stock (i.e. hake exploited in ICES Divisions VIIIa,b,d,e and all areas to the north), given the low level of spawning biomass and the likelihood that the three most recent year classes ( ) were well below average strength. ICES advice in November 2000 was for the catch in 2001 to be at the lowest possible level, accompanied by a stock rebuilding plan, including provisions to maintain a low F until a substantial increase of the SSB has been documented. The rebuilding plan should include provisions to deter directed fishing on hake, reduce by-catches of hake in fisheries for other species to the lowest practical levels, and deter discarding and mis-reporting of hake in all fisheries In December 2000, the Council of Ministers agreed a TAC for Northern hake of 22.6 Kt, accompanied by a recovery plan aimed at managing the uptake of this TAC in 2001, to introduce measures to protect juvenile hake and adults, and prepare harvesting rules to fix future TACs. In preparation for the hake recovery plan, member states with an interest in the northern hake were advised by DG Fisheries of the necessity for the following work: 1. update the typology of the fisheries generating catches of northern hake 2. specify the share by weight and value of the hake of various ranges of sizes in the contributions of the corresponding fleets 3. on the basis of log-book data, provide data charts by ICES rectangle and per month, and if possible per fishery, of the catches of hake and associated species (i.e. those taken on the same fishing day) for the three years , and for the beginning of use data from commercial catches to validate the low recruitment in the years 1997, 98 and 99, and the reduction in the spawning stock abundance. 5. update information available on the spatio-temporal distribution of immature hake and on spawning concentrations. 2

6 6. simulate the effects on the development of the spawning stock biomass and that of the catches of the various fishing units in the six years to come for scenarios corresponding to reductions in fishing mortality for: a) hake less than 27 cm b) juvenile hake more than 27 cm c) adult hake, and combinations of these reductions by size range, assuming various levels of recruitment after prepare simulations in the medium and long term, and evaluate the consequences of various harvesting rules to fix the TACs, by incorporating various "plausible" hypotheses on the stock/recruitment relationship. As the first step in preparing for the hake recovery plan, a working group of scientists from those countries chiefly involved in the exploitation of Northern hake (France, Ireland, Spain and the UK) met with the following terms of reference: 1. To review and update the assessment of the northern hake stock prepared by the ICES Southern Shelf Demersal WG in September 2000 with a view to ascertaining the current status of this stock in relation to safe biological limits. 2. Consider how best to disaggregate the assessment data into areas, fleets or métiers with which to perform simulation studies of the effects of technical measures aimed at protecting juvenile hake and harvesting rules to fix the TACs, by incorporating various "plausible" hypotheses recruitment. 3. Propose the contents of research plans aimed at improving knowledge of the hake and its fishery (not just stock assessment) in the context of a stock recovery plan. 4. Agree a schedule of modeling work based on 2 above, including a review of the biological reference points. 5. Prepare reports on the above work, to be completed for the STECF plenary meeting 2-6th April. The report of this meeting was prepared to inform a regional workshop held in Brussels by the Commission on 24 th January

7 +DNHMXYHQLOHDQGDGXOWGLVWULEXWLRQ,QIRUPDWLRQ RQ MXYHQLOH KDNH GLVWULEXWLRQV FRPLQJ IURP VFLHQWLILF ERWWRP WUDZO VXUYH\V Information is available from a French spring and autumn survey series which commenced in The survey area for this series was limited to the stock distribution south of 48º 30 N, except for the period , and in the last four years, when the survey was extended to 51º15 N. Nursery grounds in the Bay of Biscay are well delimited by the distribution of age 0 hake in these survey series. Two main patches can be identified in this area during the autumn: between 46º and 47º 30 N and south of 45º 30 (Figs.1, 2, 4 and 5 in Appendix I). These concentrations of age 0 and 1 hake are still observed during the spring (Fig. 3 in Appendix I), and are situated between 80 and 160 m depth (Figs. 6a, 7a and 8a in Appendix I). In the Celtic Sea, 0-group hake appear to concentrate at depths between 80 m and 200 m (Fig, 6b, 7b, and 8b in Appendix I ) mainly in the area delimited by the meridians 7º 30 and 9º W and the parallels 50º and 51º N. This information is confirmed by the English survey in March, in which concentrations of 1 groups are found north of 49º and west of 6º W (Figs. 9a, 9b, 10a, 10b in Appendix I). The relative abundance of age 0 between the Bay of Biscay and the Celtic Sea is variable between years, probably due to changes in environmental conditions (see distributions for years 1990 and 1997 in comparison to 1992 and 1998 in Figs. 1 and 2, 4 and 5 in Appendix I). The patterns of recruitment in the Bay of Biscay and Celtic Sea in are shown in Figs 11, 12, 13 and 14 in Appendix I. Age groups younger than 3 years old show similar distributions, both geographically and by depths in these areas, although age 2 can be found in deeper water. Catches of hake age 3 and older are scarce in these surveys and appear to have a wider distribution both in depth and area. Abundance indices of age 0 for the years 1997, 1998, 1999 and 2000, obtained from the Irish survey, were also provided to this meeting. This survey series, which covers depths down to 200 m, indicates that there may be important hake nursery areas off the west and south-west coasts of Ireland (Figs. 15, 16 and 17 in Appendix I). Information coming from DARD survey series which have taken in place since 1992 in the Irish Sea during the autumn, indicate the presence of 0 group hake in the western part of this area. There is also evidence of 0- and 1-group hake taken in Scottish surveys in the first and last quarters of the year in Division VIa. However, the abundance of hake in both these survey series is difficult to quantify at present, although it seems rather low. 'LVWULEXWLRQRIDGXOWKDNHIURPHJJDQGODUYDHVXUYH\V Data on the distributions of hake eggs and larvae, obtained during the ICES triennial mackerel and horse mackerel egg and larval surveys, show that eggs are present throughout the first 4

8 half of the year in the proximity of the slope, being most abundant during March and April. From May onwards, hake eggs tend to disappear from the southern part of the distribution area. Larvae seem to be more abundant during April and May, and appear more widely distributed over the shelf than eggs. From May, no larvae appears south of 47º N (Figs. 18 and 19 in Appendix I). )LVKHU\XQLWVLQ,&(66XE$UHDV,99,9,,DQG9,,,ZKLFKFDWFKKDNH The assessment of northern hake is based on catch-at-age data arranged by fleet unit, according to the métiers defined by the working group on fishery units in Area VII and VIII (ICES 1991/Assess:24). The composition of some of these fleets has changed considerably during the last decade. The following section describes these changes, and provides an up-todate account of the fishery units as a basis for future assessments and in relation to evaluating the need for and impact of potential technical measures aimed at improving the exploitation pattern on hake. Charts illustrating the length distribution hake in catches by fleet units, and the distribution of landings by the main gear types in national fleets (Spain, UK and Ireland) can be found in Appendix II. 2YHUYLHZ The fisheries taking northern hake mainly involve vessels from Spain and France, which take 60% and 25% of the landings respectively. England, Wales, Scotland and Northern Ireland together report about 10%, and Ireland 5%. The three main gear types used by vessels fishing for hake as a target species are otter-trawls (all countries), fixed-nets (England & Wales, Spain and France) and lines (Spain). Hake are also taken as a by-catch in a number of trawl fisheries, especially those targeting 1HSKURSV. They tend to be caught throughout the year, the peak landings being made in the summer months. From the beginning of the year until March/April, hake are taken mainly in northern Biscay, and the fishery moves to the shelf edge in the Celtic Sea in June and July. Between August and December the hake fishery is centred to the west and south-west of Ireland, with a decline in catch rates in shallower waters. )LVKHU\8QLWVRQ1RUWKHUQ+DNH Northern hake, as a target species or in a mixed fishery, is caught by a number of different gears throughout its distribution area. Historically, a set of different Fishery Units (FU) was defined by the ICES Working Group on Fisheries Units in Sub-areas VII and VIII in 1985, in order to study the fishing activity related to demersal species (ICES 1991/Assess:24). Since then they have been used practically unchanged by the ICES Southern Shelf Demersal Stocks Working Group (SSDS), and all of them continue to be related only to Sub-areas VII and VIII. In order to compare the changes in the importance of the different FU, as they were defined in the past, in relation to the landings of northern hake, data on total landings as estimated by the SSDSWG for 1994 and 1999 (51,300 t and 38,500 t respectively) have been used. The results are presented in the table in Appendix II. Métiers of the more northern sea areas of distribution of the northern hake (Divisions IIIa, IVa,b and VIa,b) and also Division VIIa, were not considered by the 1985 ICES Working Group on Fisheries Units in Sub-areas VII and VIII, and thus there is not at present a precise 5

9 definition of their FU. A general Miscellaneous or Outsiders FU (FU 16) has been used to cover the métiers of the fleets working on demersal stocks in these sea areas, though trawl in medium-deep waters and long line are two important fleet components that could be identified there. This FU 16 accounts for 11% and 9% of northern Hake total landings both in 1994 and Vessels from mainly the UK, but also Denmark, Norway, Spain, France and Ireland (by order of landings) are concerned in this imprecise FU in both years. In the Celtic Sea (Divisions VIIe-k), seven or eight more clear-cut métiers are involved, but only three of them account for significant amounts of hake. Notable changes have been observed in the relative importance of these three FU since 1994: The benthic trawling fishery, i.e. the non-nephrops trawling in shallow water (FU 4), accounted for the largest proportion of total northern hake landings in 1999, having increased in relative importance from 18.0% in 1994 to 23.4% in Several countries are involved in FU4, mainly Spain (73%), UK (19%) and France (8%) in The long line in medium to deep water fishery for hake (FU 1) was equally important for northern hake landings in 1994 (18%), but its importance has decreased to 16% in Spain continues to be the main country involved in it. The gill net fishery (FU 3) increased markedly from 2.3% in 1994, when only the UK was involved in it, to 10.6% in 1999, when three countries: Spain (45%), UK (30%) and France (25%) used gill nets for hake. The remaining FUs amount for less than 2% of total landings of northern hake in the same period: The long line fishery in shallow water (FU 2) mainly involves France. Non-Nephrops trawling in shallow water (FU 5): principally Ireland and secondary France and UK in 1994, but in 1999 principally France and then UK. Beam trawling in shallow water (FU 6) is limited to UK (ZKDWDERXW%HOJLXP" Nephrops trawling in medium water (FU 7+8) is almost totally restricted to France. In addition, a relatively important proportion (6% and 7% in 1994 and 1999 respectively) of the total landings of northern hake are due to the so called Miscellaneous Fishery (FU 15) that operates in the Celtic Sea or in the Bay of Biscay. This FU corresponded in the 80s to various French métiers operating inshore in the Bay of Biscay and fishing mostly for sole and hake: chiefly trawlers, shrimps trawlers and gill-netters for sole which could change very quickly from one métier to another. In 1994, the landings of this FU were made chiefly by France, but in 1999 most of them were due to Ireland and secondarily to France. In the Bay of Biscay (Divisions VIIIa,b,d), there is a total of 5 métiers whose relative importance has changed notably in the two years considered. They are presented by order in relation to their contribution to the total landings of northern Hake in 1999 The trawling in deep and medium depth (FU 14), which traditionally involves very different trawl gears used by Spanish vessels, continues to account for the largest proportion of the hake landings in the Bay of Biscay. It accounted for 15% and 14% of total landings of northern stock in 1994 and 1999 respectively. During the period , considerable 6

10 changes have taken place in the relative composition of Spanish trawlers by specific metier see the description of Spanish fleets below. Landings of the northern stock of hake by the gill net fishery (FU 13) in the Bay of Biscay increased markedly from 2.3% in 1994 to 10.6% in 1999, when this FU occupied second position in total landings. In 1994, only France was involved in it, but in 1999 Spain and France were almost in the same proportion. It is evident that the gill net métier in both sea areas considered together -Celtic Sea, FU 3, and Bay of Biscay, FU 13- have recently experienced a large proportional increment in the landings of northern hake. The French Nephrops fishery trawling in shallow to medium depth (FU 9) has increased its relative importance in the total landings of northern hake from 1994 (2%) to 1999 (3.4%). The long line fishery in deep to medium water (FU 12), that had a relatively high importance in the hake fisheries in the Bay of Biscay in the 1980s and beginning of the 90s, has decreased markedly since 1994 (6.4% of total landings of northern stock) to 1999 (2.1%). Spain continues to be the country most involved in this fishery. The trawling in shallow to medium water (FU 10), carried out only by French vessels, had a relatively greater importance in the past with respect to the total northern hake landings, but has diminished to a great extent from 1994 (10.4%) to 1999 (1.4%). This Working Group suggests that, in the future, the possibility of splitting some of the FUs in order to achieve a more precise monitoring of hake catches should be considered. Differences in the target species, in the exploitation pattern and in the dimensions of the gears used by the different fleet components, as well changes observed in the proportion of these components in recent years, could support this eventual splitting. As an example, in the case of the FU 4 and FU 14 (trawling in deep and medium depth), five components have been included in the same FU throughout the 80s and 90s: the baka-trawl, the bou-trawl (which was very important in the 80s and 90s, but practically disappeared in 2000), the traditional pair-trawl, the new pair-trawl (operating with Naberan nets) since 1993, and the recently introduced boats operating with twin nets. 1RUWKHUQ+DNHFRPSRVLWLRQVE\)LVKHU\8QLWDQG6XEDUHD In Appendix II, the length distributions of hake landings in 1994 and 1999 for the more important Fishery Units in Sub-area VII and Divisions VIIIa,b,d are presented. They are based on the information provided to and compiled by the SSDSWG. Sub-area VII (mainly Celtic Sea) In some cases, important changes in length compositions by Fishery Units in can be observed between 1994 and 1999: The long line in medium to deep water fishery (FU 1) shows evidence of a reduction in the number of fish in the largest sizes from 1994 to The gill net fishery (FU 3) shows two main differences: the great increment of fish from 1994 to 1999 and the relative decrease of the mean size for the same years. The benthic (medium and deep water) trawling fishery (FU 4) presents a very different pattern from 1994 to 1999, but it must be viewed with caution. The big proportion of fish less than 30 cm length observed in 1994 could be due to a relatively strong year class. 7

11 The so called Miscellaneous Fishery (FU 15) for Celtic Sea and Bay of Biscay shows a notable increment of fish of more than 40 cm length from 1994 to But, as this metier is so imprecise, their implications are difficult to interpret. Divisions VIIIa,b,c (Bay of Biscay) Here also, important changes can be observed in the length compositions of hake in in some Fishery Units between 1994 and 1999: The 1HSKURSV fishery trawling in shallow to medium depth (FU 9) shows a reduction in the number of fish from 1994 to 1999, except for fish between cm length. The trawling in shallow to medium water (FU 10) shows a notable decrease, mainly in the number of fish and also in the relative mean size of fish landed between 1994 and The long line fishery in deep to medium water (FU 12) shows a marked reduction in the number of fish landed from 1994 and 1999, but a relative increase of the mean size. The gill net fishery (FU 13) shows a remarkable increment in the number of fish from 1994 to 1999, but it is not possible to detect changes in the fish sizes from these data. The trawling in deep and medium depth (FU 14) presents a very different pattern from 1994 to 1999 in three aspects: the marked reduction in the number of fish, the near absence of fish less than about 25 cm, and the increase of the mean size, and there is also a reduction of fish of the largest sizes. The absence of fish of the smallest sizes can be explained by the very low recruitment levels observed for the northern hake in the last few years. The changes observed between 1994 and 1999 in the absolute and relative number of each of the gear components of the trawling and, consequently, in the combined effect resulting of the modus operandi of each sub-metier, can explain the rest of the differences in the total number of fish and in the mean sizes. 8

12 )OHHW'HVFULSWLRQV 'HQPDUN)OHHWV The whole Danish catch of hake is taken in FU 16 in ICES Divs. IVa,b and IIIa. Landings by fleet are available for the years , when they have been less than 1000 t. Gillnets account for most of the Danish landings and, for some years, a gillnet fishery targeting hake has been conducted in the North Sea in the Horns Reef area. Otherwise, the main catches are taken in the bottom trawl fisheries for 1HSKURSV and for demersal fish, and in Danish seine fisheries, see table below 7RWDO'DQLVKODQGLQJVLQWRQQHV Gear: Tonnes % Gillnets Trawl, 1HSKURSV Trawl, demersal fish Danish seine Other gear Total landings: Discard data which include length measurements have been collected for some of these fisheries in recent years. 6SDQLVKIOHHWV Spanish vessels that fish for northern hake as a target or in a mixed fishery for anglerfish, megrim, Nephrops and other species, can be assigned to seven FUs as defined by the ICES Working Group on Fisheries Units in Sub-areas VII and VIII (ICES 1991/Assess:24): FU 1 Longlines in medium-deep waters, in Sub-area VII FU 3 Gill nets, in Sub-area VII FU 4 Non1HSKURSVtrawl in medium-deep waters, in Sub-area VII FU 12 Longlines in medium-deep waters, in Sub-area VIII FU 13 Gill nets in medium to shallow waters, in Sub-area VIII FU 14 Non-1HSKURSVtrawl in medium-deep waters, in Sub-area VIII FU 16 Outsiders, in Sub-area VI The Spanish fleets in the northern demersal fisheries are composed of trawlers (with different gears: type baca, bou and pair), longliners and gill nets. The duration of their trips varies considerably, depending mainly on the fishing area, the métier and the base port, and its traditional pattern has varied very much since the mid-1990s in some Spanish regions. Thus, the former trip duration of ships working in Sub-area VI (about 21 days, of them 7 or 8 for travel) has changed (about 6 days), because they have began to land their catches into Scottish ports and to transport them by trucks to the own base ports for selling. In the past, the mean trip duration for trawlers in Divisions VIIIa,b,d was about 5-7 days, and about 17 days in Sub-area VII (4-6 days for travel), but at the end of the 90s, Basque Country trawlers working in Sub-area VII tended to do trips of about 6 days because they landed most of the 9

13 catches in Irish or southern British ports. Some Basque trawlers working in Divisions VIIIa,b,d use to do trips of 5-6 days and to land in French ports. The Spanish landings of the various fleets in Divisions VIIIa,b,d and Sub-areas VI and VII are shown in Appendix II, as is the geographical distribution of the CPUEs by ICES statistical rectangles of these fleets obtained from the logbooks for UDZOIOHHW Traditionally, the bottom trawl fleet is composed of vessels that fish individually ("bacas" and "bous") and those that fish in pairs ("parejas"). In 1994, the proportion of each of these three trawl fleet components was: about 86% of "bacas", less than 10% of "bous" and less than 4% of pairs". Since then, there has been an increase in the pair trawl and a constant decrease of the baca-trawl. The bou-trawl fleet had practically disappeared in The target species for trawlers are hake, megrim, anglerfish and, at a lesser level, 1HSKURSV and other species, depending on the year period and market conditions. In 2000, one Spanish boat began to work with twin nets. The traditional bottom pair trawlers (usually composed of two old "bacas") disappeared in the early 90s, but a new métier of bottom pair trawlers with Naberan nets was introduced in The nets of this new métier achieve a very high vertical aperture (VHVO) in the net mouth and they are very efficient for hake. They began to work in the Bay of Biscay, but in the last years some boats have fished during part of the year in the Celtic Sea. In 1993, only one VHVO pair trawler was working, in 1999 twelve pairs, but since 2000 its number has began to decrease. Hake landings from both sea areas together remain rather constant around 5,600 t from 1995 to In 1999, 4,400 t were caught in the Bay of Biscay and 1,284 t in the Celtic Sea. The mean length of hake total landings of new pair-trawls in the period is about 36 cm (35.3 cm from Divisions VIIIa,b,d and 40.1cm from Sub-area VII). The CPUE of this fleet has decreased since 1994.The origin of these pair trawlers in 1995 was: old 'bacas" trawlers (10), old "bous" trawlers (4) and only 2 ships of new construction following decommissioning of old vessels. Effort data related to the ports which are most representative of fleets operating in Sub-area VII and Divisions VIIIa,b,d have been usually employed to tune the ICES VPA assessments for hake and megrim. In general, the effort of baca trawlers fishing in Sub-Areas VI, VII and Divisions VIIIa,b,d show a constant decrease, which is consistent with the reduction in the number of boats. Since 1994, an important part of the baca trawler fleet that operates mainly in the Celtic Sea (Divisions VIIj-k) had been renewed under IFOP, with improvements in the technology of fish capture and the fish manipulation, but there has been no change in the number of fishing days. These improvements allow these trawlers to freeze and process part of the catches on board and, consequently, to achieve a higher economic profitability of the catches. /RQJOLQHIOHHW This fleet continues to target hake in the more northern areas: Sub-areas VI and VII. In Divisions VIIIa,b,d, where this fleet has very successfully fished hake after its implementation in the 80s and until mid-90s, the CPUE had diminished considerably by the end of 90s and, consequently, the number of boats involved has reduced. Some of them have 10

14 been decommissioned, and others have changed to another métiers (pairs trawls or gillnets) or to another target species (deepwater species). *LOOQHWV Though gill net gear was allowed to operate in Divisions VIIIa,b,d and Sub-areas VI and VII in 1997, the fishery did not start until 1998In 1998 and 1999, the hake catches of this fleet were maintained at the same level and represented 12% of the Spanish landings from Divisions VIII a,b,d and 29% from Sub-area VII. The target species is hake and the catches are based mainly on adult fish (30-90 cm). 8.IOHHWV A table showing the UK (England, Wales, Northern Ireland and Scotland) landings of hake is given in Appendix II, along with charts showing the distribution (by ICES statistical rectangle) of hake landings by six gear types. 6XEDUHDV,9DQG9,1RUWK6HDDQG:HVWRI6FRWODQG^35,9$7(` Hake are not considered an important target species by Scottish fishermen, although they can form a valuable component of the by-catch from the main mixed fisheries for cod, haddock, whiting and monkfish. Over the last decade, hake landings have fluctuated between 0.4% and 1.1% of the total demersal landings by Scottish vessels. Although hake are caught in the North Sea, the main fishery is on the west coast of Scotland. Hake are caught widely and throughout the year in within ICES sub-areas IVa, IVb and VIa, with the highest catches occurring south of Barra Head and on the Stanton Banks in the spring and summer. The vessels mainly exploiting hake are small demersal otter trawlers targeting either gadoids or 1HSKURSV. 2WWHUWUDZOURXQGILVK Most of the landings of cod, haddock, whiting and a smaller proportion of the saithe, are taken in a mixed roundfish fishery in VIa. This fishery is largely Scottish, with lesser involvement by boats from France, Ireland, Northern Ireland, and England and Wales. This fishery tends to operate as an extension of the similar fishery in the North Sea, and many boats from the Scottish North Sea ports also fish west of Scotland. A small number of seiners also participate in this fishery. 2WWHUWUDZO$QJOHUDQG0HJULP A substantial proportion of the Scottish fleet has started to target anglerfish and megrim west of Scotland. These boats originally formed part of the mixed roundfish fleet, and still land roundfish, particularly haddock and cod. A number of English-registered Spanish boats also participate in this fishery. 11

15 2WWHUWUDZO1HSKURSV 1HSKURSV are taken by trawlers from grounds relatively close inshore, particularly in the Minch and Firth of Clyde areas. These boats, which are almost exclusively Scottish, also land small quantities of roundfish including hake, but discard larger quantities of whiting and haddock. 'LYLVLRQ9,,D,ULVK6HD 1HSKURSVWUDZO This is numerically the largest métier in the Irish Sea. Over 200 boats (113 NI vessels in 1999) target 1HSKURSV on areas of muddy seabed in the western Irish Sea and off Cumbria, which are also the main nursery grounds for whiting. This gear takes a considerable by-catch of whiting, and small amounts of other species, especially cod and plaice. The smaller vessels mainly use single otter trawls with a minimum cod-end mesh size of 70mm plus a square mesh panel (SMP) of 80mm to enhance escapement of undersized gadoids. The more powerful trawlers are able to tow two standard 1HSKURSV trawls in a twin-rig, using 80 mm diamond mesh with 80 mm SMP, though when cod and haddock are 'plentiful' these vessels will change over to 100mm nets. A third type of 1HSKURSV trawl is fished singly and is designed with a larger fishing circle and higher headline lift to optimise the mixed catch of prawns and fish. This gear takes a by-catch of hake in rectangles 36E4, 37E4 and 37E5, along with whiting, cod, haddock and plaice. Many boats, especially the larger ones, interchange freely between this métier and that of the whitefish bottom trawl. :KLWHILVK2WWHUWUDZO The number of vessels using otter-trawls to take cod, plaice, whiting, haddock, anglerfish, hake, sole, rays and other demersal species has decreased in recent years. A small fleet of NI vessels use whitefish otter trawls (13 in 1999) and take a by-catch of hake particularly during spring and summer over a wide area. The activities of French otter trawlers is confined mainly to the southern regions of the Irish Sea. A small fleet of Irish otter-trawlers targets gadoids in the Irish Sea, but has recently developed a fishery for rays in the St George's Channel, where the use of bobbins and later a 'rockhopper' gear has increased its capacity to fish different types of ground. 6HPLSHODJLFWUDZOV A fishery for cod, haddock and hake using large semi-pelagic trawls commenced in the early 1980s. In 1999, 41 Northern Ireland trawlers used this gear to target cod until the end of April close to the spawning grounds in the western Irish Sea. During the remainder of the year, hake are taken by semi-pelagic trawl in the deeper waters of the western Irish Sea, in particular the North Channel (ICES rectangles 38E4 and 39E4, straddling the VIIa and VIa boundary), and in deeper water at the southern end of the western Irish Sea Nephrops grounds (36E4). Some of these vessels switch between this métier and twin-rig trawling for Nephrops, depending on availability of fish and market demands. /RQJOLQH There is still a small longline fishery for spurdogs, rays, cod and hake throughout the Irish Sea. 12

16 'LYLVLRQ9,,H:HVWHUQ&KDQQHO Hake is not considered a target species by the vast majority of UK vessels fishing in VIIe, where they form a small but valuable proportion of catches taken by otter and, to a lesser extent, beam trawl. A small number of gill-netters do target hake in VIIe. 2WWHUWUDZO Otter trawlers from England and the Channel Islands exploit a mixed fishery all year round, switching their target species depending on market demand and tide. Cod, haddock and whiting can be targeted at various times and locations throughout the year, as can John dory. There are two distinct seasonal fisheries: in autumn, when a large number of boats (up to 80) target squid and cuttlefish between Start Point and Portland; and in spring, when there is a traditional lemon sole fishery off Looe and Falmouth Bay, although this has declined somewhat in recent years. Very little hake is taken as a by-catch east of the Lizard. %HDP7UDZO The area is heavily fished by English and Belgium beam-trawlers, which target plaice, sole, monkfish, megrims (west of the Lizard) and cuttlefish. However, these vessels take a bycatch of many species including hake and John dory. 6WDWLFJHDU The UK gill-net fishery for hake in the South-west started in Division VIIe in the early eighties, when boats targeting spurdog discovered large shoals of hake off the Lizard. For many years, boats fished SE of the Lizard (ICES rectangles 27E4, 27E5 and 26E4) during spring, often with a significant by-catch of large bass. The boats would then move west towards grounds south of the Isles of Scilly during late September - early October. These fisheries, particularly the spring one, took a downturn in the late 1990s, but a greatly reduced fleet has recently made significant landings of hake and ling during February - March from the middle of the Western English Channel. All boats use a mesh size greater than 120 mm. While the number of netters has decreased recently, the number of nets (each of 90 m) worked by each vessel has increased from an average of 90 to 100 per boat to 140 to 160. Tidal conditions limit hake gill-netters to a maximum of 160 days fishing a year. There are also many under 12m vessels which use various types of gill/tangle nets, but these rarely now target hake. French vessels gill-netting in this area appear to have concentrated on wrecknetting or tangle-netting. 'LYLVLRQV9,,IN&HOWLF6HD^35,9$7(` According to the working group on Sub-areas VII and VIII (ICES, 1991), four métiers were identified as taking 90 % of the total hake catch in Sub-areas VII b-k (except VIIde, Channel): 2WWHUWUDZO See VIIe. UK trawlers rarely venture further than 7 W. 13

17 %HDP7UDZO Beam trawlers in this area either target plaice and sole in VII f,g or monkfish and megrims in VIIh. Very few beam trawlers fish west of 7 30 W. The hake by-catch of beam trawlers has appeared to increase in Belgian Eurocutter style beam trawlers are now much less active in ICES Area VII f,g. 6WDWLFJHDU As in VIIe, the number of dedicated UK hake netters declined from approx. 30 in 1994 to less than 10 by the end of 2000, when the annual days at sea directed at hake decreased from over 2000 to The remaining static gear vessels (of a total of 25 in 2000, down from a maximum of 60 in 1992/93) are more flexible, choosing to spend a quarter of the year tanglenetting (rays, turbot and monkfish), a quarter wreck-netting (cod and ling) and at most half a year hake netting, fishing as far as 10 W when the weather allows. The boats follow the fish east through March, April & May, fishing at the Pestola and then Labadie Banks. Although the amount of gear deployed per boat has increased, as in VIIe, this has now reached a maximum due to the physical capacity of the boats. Since 1995/6, the Anglo-Spanish gill-net fleet in this area has appeared to increase considerably. These vessels are much larger (often over 30 m in length) and work more gear than Cornish boats. There is also a small long line fishery which takes mostly hake.,ulvkiohhwv Since 1989, there has been a substantial increase in the polyvalent nature (multipurpose vessels; periodically switching gears, areas of operation and target species) of the Irish fleet. The demersal fleet has been defined into two categories of vessels, the beam trawl and the large polyvalent fleet. The polyvalent fleet takes most of the Irish catch of hake and can be partitioned into vessels of less than 15m, 15-20m and greater than 20m overall length. Vessels under 15m make up the bulk of this fleet. The Irish fleet consists of approximately 1,500 vessels with a total Gross Registered Tonnage of 56,686 tonnes. The demersal fleet, which take all the Irish hake catches, consists of approximately 1,300 vessels (>10m) which mainly operate in ICES Sub Areas VI and VII using otter trawl, beam trawl, seine and fixed nets. The demersal fleet consists of older vessels (mainly 15 to 30 years), and there are four main segments; the beam trawl fleet (approximately 20 vessels); the inshore artisanal (<15 m, 873 vessels); the inshore multipurpose (15-20 m; 216 vessels) and the offshore multipurpose (>20 m 132 vessels). During 2000, up to 30 new vessels (20 to 35 m) entered the Irish fleet under the whitefish renewal scheme. These new vessels will mostly target mixed demersal fisheries in Sub Area VI and VII. It is very difficult to break down the demersal polyvalent fleet into exclusive segments in terms of target species, gear types or area of operations, due to its dynamic nature. One approach has been to define segments based on the total length of vessels. This gives four broad categories. 14

18 The EHDPWUDZl fleet is the smallest segment, with 20 vessels engaged in beam trawling for sole, plaice, anglerfish, brill, turbot and dredging for scallops, mainly in Division VIIa and VIIg. There is a small by-catch of hake.,qvkruhduwlvdqdo which consists of approximately 873 vessels of less than 15 m total length, engaged in dredging, fixed netting and trawling for mainly non-tac species. Landings include cod, whiting, haddock and hake in inshore waters. There are approximately 216 LQVKRUH PXOWLSXUSRVH vessels in the length range m, engaged in demersal and pelagic trawling and using fixed gears for cod, haddock, whiting, plaice, sole, hake, megrim, anglerfish and some non-tac species in inshore and (sometimes) offshore waters. Some 132 RIIVKRUH PXOWLSXUSRVH vessels greater than 20 m total length are engaged in demersal and pelagic trawling, beam trawling and using fixed lines and nets to take the same range of species as above, plus cod in Division IIa, deep water species and tuna.,ulvkiohhwdfwlylw\ The Irish Demersal fleet operating in Division VIIb,c target 1HSKURSV and the mixed fisheries for hake, anglerfish, megrim, cod, whiting, plaice and sole. Fishing in Division VIIb,c is carried out mainly in inshore waters (west of the Aran Islands) and offshore during the summer months on the Porcupine Bank. The main gear used is otter trawl, with twin-rig trawl and gillnetting of less importance. Fishing activity by the Irish fleet in Division VIIj,k is mainly by trawl and fixed gear, targeting megrim, anglerfish, hake and tuna. Fishing in Sub Area VI is carried out by otter trawl mainly targeting cod, whiting, haddock, megrim and anglerfish. Hake are a by-catch of this fishery. The Irish Sea gadoid fishery has declined in recent years, but small catches of cod, whiting and haddock are still taken by otter trawl. The 1HSKURSV (otter-trawl), plaice and sole (beam-trawl) fisheries remain important in the Irish Sea. In Division VIIg, the main fleets target cod, whiting, haddock, 1HSKURSV, plaice and sole using trawl gear and fixed nets. The total Irish landings of hake taken by all gears in 1999 was approximately 2,100 t. Based on 1999 EU logbook data, the main Irish hake catches are taken in the first and fourth quarters along the shelf edge, in the Porcupine Bank area and in Division VIIg. Smaller catches are taken in Division VIa and VIIa. Otter trawlers take about 70% of the hake landings in mixed demersal fisheries, with cod, haddock, whiting, anglerfish and megrim. Gill netters taking about 14% of hake landings, with associated catches of cod, ling and pollock, mainly in the 1 st and 2 nd quarters. Seiners take about 10% of the landings of hake, with associated catches of whiting and haddock mainly in Divisions VIIj and g. The landings of hake by the main Irish gears for 1999 are shown below, together with the associated fishery units. Charts showing hake landings by five gear types and by quarter for 1999 are given in Appendix II. *HDU /DQGLQJVW 3HUFHQWDJH )LVKHU\8QLWV Fixed Nets , 15 Otter Trawl 1, , 5, 7, 8 (also Div VI) Pair Trawl Seiners (mainly Div VIIe-k) Beamers

19 )UHQFKIOHHWV The results of an analysis of the fisheries statistics available to IFREMER for the years 1990 and 1998 given below shows the contributions to the main fishery units to the landings of hake, and their evolution. Hake Base Gear Other VII VIII Total Unknown various Lines gillnets Demersal trawl Pelagic trawl Total Hake 1998 Gear Other VII VIII Total Unknown Various Lines Gillnets Demersal trawl Pelagic trawl Total It can be seen that the landings of hake by French vessels were much lower in 1998 than they were in 1990, and that the largest proportion came from the Bay of Biscay, and then the Celtic Sea. In 1990, pelagic trawlers contributed the highest quantity of hake in French landings, at around 6800 t, whereas in 1998 they produced only 6%, some 500 t. In 1990, nearly three-quarters of hake landings by pelagic trawl were coming from trips targeting hake (more than 40% of hake in landings). Following the reduction in landings of hake from pelagic trawls, gill nets have become the second most important gear type after demersal trawls. $ UHYLHZ RI WKH DVVHVVPHQW RI WKH QRUWKHUQ KDNH VWRFN SUHSDUHG E\ WKH,&(6 6RXWKHUQ6KHOI'HPHUVDO:*LQ6HSWHPEHU ACFM s (November 2000) interpretation of the assessment carried out by the SSDS WG in September 2000 was that the spawning stock biomass (SSB) at January 2000 (at 88 Kt) was at the lowest level observed in the time series ( ), well below the value of Blim (120 Kt). Fishing mortality in 1999 (at 0.38) was well above Flim (0.28), and had been at or above this level for the previous five years. ACFM concluded that the stock is clearly outside safe biological limits and, with three successive low recruitments, likely to decline further. This Working Group revisited this assessment, giving special attention to the three issues that were raised by various parties, namely: 16

20 1. the low recruitments indicated for the 3 recent year classes ; 2. the abrupt rise in F, and concomitant sharp decrease in SSB, from 1998 to 1999; 3. the low catches predicted for 2000 under status quo F. Reading through the ICES WG report and examining the VPA diagnostics for northern hake, this Group did not detect any serious problem with the way the assessment was handled by SSDS. However, the ICES assessment was obtained after a critical selection of fleets and age ranges used for tuning. In order to evaluate the effects of this selection, the Group examined the results of a comparative assessment using all available data for tuning. The main differences in input between the ICES assessment and this 'comparative assessment' are summarised in the text-table below; all other settings were unchanged. Fleet ICES Comparative SP-CORUTR7 (Commercial) ages 5-7 ages 2-7 FR-LESCONIL (Commercial) ages 0-1 ages 0-5 FR-SABLES (Commercial) ages 1-5 ages 0-5 FR-RESSGASC (Survey) ages 0-5 ages 0-5 UK-WCGFS (Survey) not used ages 1-2 The output tables of fishing mortality and stock numbers at age, and the assessment summery table, are given in Appendix III. The general trends indicated by the comparative assessment are quite consistent with the results obtained by ICES SSDS in September Regarding issue 1), one might have expected that the inclusion of the UK survey, which had relatively high indices for age 1 in 1997 and 1999, would change the outcome. Although slightly larger values were estimated for the recruitments in , it is confirmed that these are all well below what has been seen in the history of the hake stock. This outcome is also consistent with the indications given by various surveys, including those that were omitted from VPA, to serve as independent checks (Figure 5.1). 17

21 5HFUXLWPHQWLQGLFHV 5HFUXLWPHQWLQGLFHV 5HFUXLWPHQWLQGLFHV VPA_0 VPA_0 VPA_ FR-Ressgasc_ FR-Lesconil_ UK-WCGFS_ à H J ÃD Ã1 D S [ H G W ÃLQ Q H P LW X U F H à H J ÃD Ã1 D S [ H G W ÃLQ Q H P LW X U F H à H J ÃD Ã1 D S [ H G W ÃLQ Q H P LW X U F H <HDUÃFODVV <HDUÃFODVV <HDUÃFODVV 5HFUXLWPHQWLQGLFHV VPA_0 FR-EVHOE_0 5HFUXLWPHQWLQGLFHV VPA_0 IR_0 5HFUXLWPHQWLQGLFHV VPA_0 Eggs survey à H J ÃD Ã1 D S [ H G W ÃLQ Q H P LW X U F H à H J ÃD Ã1 D S [ H G W ÃLQ Q H P LW X U F H à H J ÃD Ã1 D S [ H G W ÃLQ Q H P LW X U F H <HDUÃFODVV <HDUÃFODVV <HDUÃFODVV )LJ+DNH&RPSDULVRQEHWZHHQUHFUXLWPHQWHVWLPDWHJLYHQE\WKHFRPSDUDWLYHDVVHVVPHQWDQGLQGLFHVIURPVRPHIOHHWVRUVXUYH\V 18

22 On the second issue, the sharp rise in fishing mortality from 1998 to 1999, the comparative assessment gives a smoother exploitation pattern for 1999 and brings the estimated Fs at ages 3 and 4 more in line with values observed for these in the last decade. Whilst this assessment may appear more satisfactory, it still indicates an increase of F from 1998 to 1999, although to a lesser extent (+23% instead of +32%). Likewise, the point estimate of SSB in 1999 is larger than the ICES estimate, but the reduction from 1998 to 1999 is still apparent and this SSB is among the lowest observed for this stock (about 120,000 t, similar to estimates for V Q LOLR P Ã H J D R-comp R-WG ,4 0,35 0,3 \ OLW W D 0,25 U R 0,2 J LQ K 0,15 LV ) 0,1 0,05 F-comp F-WG W Ã % SSB-comp SSB-WG )LJÃÃ1RUWKHUQÃ+DNHÃFRPSDULVRQÃEHWZHHQÃ,&(6:*ÃDQGÃFRPSDUDWLYHÃDVVHVVPHQWÃUHVXOWVÃIRUÃ66%Ã5ÃDQGÃ) 1996) (Fig. 5.2). 19

23 To examine the third issue, the low predicted catch for 2000, the results of this VPA were then input into the catch prediction using the same procedure as the ICES WG (average exploitation pattern and mean weights over the last three years, no scaling of F to the 1999 estimate, partition into landings and discards Fs). The landings for 2000 under status quo F are predicted to be 30,700 t when recruitment in 1999 is kept as estimated by XSA, or 30,600 t when it is replaced by the average for 1997 and 1998, as done by ICES. The difference is negligible, indicating that the result is not sensitive to the treatment of incoming recruitment (cf. ACFM comments). This prediction is some 3,500 t larger than the ICES forecast, but such a difference (13%) is well within the noise usually assumed for most assessments (30% at best). Only when status quo F is defined as the average exploitation scaled to the 1999 estimate does the prediction (34,200 t) come closer to the 38,000 t figure mentioned to the Group. However, this option is controversial and may not be appropriate if the high value for 1999 is just an effect of noise, and likely to be revised in subsequent assessments, rather than the end point of a trend for which there is little supporting evidence. It should also be kept in mind that, if a higher F matches some criteria more closely in the very short term, it will have the effect of leading to a more severe decline of SSB further below precautionary thresholds in the predictions for It is concluded from this comparison that the selection of tuning data made by the ICES WG is not the cause of the issues raised. Other possible causes were considered by this Group. One of these is the procedure for length-to-age conversion, using an annual rather than quarterly ALKs (cf. ACFM minutes). However, it is likely that this would mostly affect the allocation of catches among the age groups in which growth is fast within the year, i.e. ages 0-3. In the data, the catch numbers for these ages are all very small, and moving a few fish from one age to the adjacent ones is not likely to significantly change the assessment. Another reason often put forward for discrepancies in assessments is that the effort data used in tuning series do not account for changes in efficiency. In this meeting this could only be explored in an DG KRF way, using the tri-cubic down-weighting option proposed in XSA. The results of this trial were worse in several respects, because it gave more emphasis to recent years in which data are missing (French fleets) or residuals larger than usual (UK survey). The outcome of this review is that, given the existing data and unless they are proved wrong, no reasonable change in the technical options for the assessment would be sufficient to significantly alter the diagnostic on this stock regarding its current state and recent trends. This Group also wishes to put forward the following points: - There is no objective basis to decide which of the ICES assessment or the comparative assessments is better. Both belong to a family of equally plausible interpretations of the data, given the likely range of uncertainty that may affect these. The major fact is that both indicate trends in the same directions for the key indicators (recruitments, F and SSB). Arguments in favour of the comparative assessment are that it includes more information in the tuning and produces a smoother exploitation pattern in the final year, but these are entirely subjective. - With a VPA-based methodology, it is unavoidable that the very low catches of ages 0-2 since the year class 1997 will translate into low estimates of recent recruitments, whatever tweaking is made with the tuning options. No technical explanations for these low catches or doubts about them were raised by the experts present. If they had been due to a change in technical measures or their enforcement, this would manifest as a change over several ages from one year to the next, not as a gradual change along cohorts as shown by the catch-at-age data. A decrease in recruitment thus appears to be the only acceptable explanation for these 20

24 reduced catches at the moment, and is supported by fishery-independent data from various sources. - The occurrence of three poor year-classes in a row implies that SSB will receive abnormally low contributions in years to come. It is therefore all the more important to reduce fishing mortality on all ages, in order to avoid SSB falling to very critical levels for a prolonged period. - Even though there have been documented changes in fleet behaviour in recent years (see Section 4) there is no firm evidence to explain, or reject, the increase in F in 1999 indicated in both assessments. Such changes are always difficult to trace in real time and only when a few more years data are added to the VPA can these be confirmed. - The Group takes note that the ICES forecast of landings for 2000 may have been an underestimate, but could not resolve the case in a satisfactory way. The issue will have to be examined later in the year, when the data for 2000 are available for inclusion in a formal assessment. The Group notes, however, that the increase in catches in Sub-area VII, observed by some segments of the industry, is not supported by the official figures reported to the Commission (up to November): these indicate lower catches in Sub-area VII, but a slight increase in Sub-area VIII, in 2000 compared to 1999 (see Table 5.1 below). There is, therefore, no justification to depart from the current status of this stock as advised by ACFM in November Table 5.1. Catches of hake by EU member states as officially reported to the EC. TAC area IIIa-d IIa, IV Vb, VI, VII, XII, XIV VIIIa,b,d,e Total ) EC waters; 2) up to November XJJHVWHGLPSURYHPHQWVIRUWKHDVVHVVPHQW The Group is of the opinion that if there are problems with the northern hake assessment, these lie with the basic biological and fisheries data and that significant improvements can only be achieved if the basic data are improved in quantity and quality. Efforts in the following directions are suggested: Fisheries data: improved effort (CPUE) data, including more of the important fleets and more complete coverage of the stock s distribution; Biological data: better age-length keys (improved age sampling of the whole population); better discard data for the métiers where these are significant; More and better data in general from the fisheries in the northern areas. The Group also discussed the problem of definition of the European hake stock(s): Is there one single hake stock distributed from ICES Sub-area VIII in the south to Sub-areas VI, IV and III in the north? Or is it more reasonable to assume more than one hake stock in these areas? This problem seems particularly relevant in the current situation where the single 21

25 Northern hake stock and its exploitation are assessed on the basis of fisheries data and biological data from mainly France and Spain, covering the southern distribution areas only. In Section 6, the Group considered the option of separate assessments for Sub-area VIII and for Sub-area VII + the northern areas, as suggested by DG-FISH. Whichever route is taken, it will be critical that more biological data from the northern distribution areas (IIIa, IV and VI) be made available. In this connection, the Group was informed that improved Danish figures for catches and discards in , as well as length frequency data covering Sub-area IV and Division IIIa, will be provided to the 2001 ICES WG meeting. The Group noted that, at present, the tuning series used in XSA sometimes give conflicting estimates of survivors. Reasons for this should be investigated. 6HSDUDWLRQRIWKHQRUWKHUQKDNHVWRFNDVVHVVPHQWLQWRRQHIRU$UHD9,,,'LYLVLRQV 9,,,DEGHDQGRQHIRUQRUWKRI 1 The assessment area for northern hake extends northwards from the Gulf de Cape Breton in the Bay of Biscay to the northern limit of the species range on the Norwegian coast. At present, there is no evidence for separate stock units of hake within this area. However, the hake TAC for this management unit is split between Sub-areas II & IV (.87 Kt in 2000), III (.75 Kt), VI VII XII XIV (13.9 Kt) and VIII (7.0 Kt), based on the forecast from a single assessment using hake catches from the whole region. It is, therefore, assumed that management of hake fisheries already recognises the differences in the make-up/combinations and character of member states fleets between these areas. Recent trends in the landings of hake from the northern stock assessment area show a sharp decrease in the Bay of Biscay, whilst in the Celtic Sea and to the north, landings are reported to be more or less stable. Fishermen have reported increased landings from Area VII in 2000, even though this increase is not evident in the official Commission statistics (see Table 5.1). CPUE from commercial fleets operating in Areas VII and VIII also show conflicting trends. French EVHOE surveys conducted in November tend to indicate alternate fluctuations in the strength of the age 0 indices between the Celtic sea and the Bay of Biscay (see Section 2). For these reasons, the Group was asked to attempt to make separate assessments for those parts of the northern hake stock in the Bay of Biscay and to the north of 48 N, in order to examine the possibility that there are different trends in SSB or R within these areas. However, even though the tuning fleets used in the assessment are segregated by area, it is not possible to split the whole catch at age matrix, since disaggregated data are only available since Furthermore, a common ALK is applied to the total northern stock catch data, and the sampling design does not allow area-specific ALKs to be reconstructed. It was concluded, therefore, that meaningful separate assessments of hake in the Bay of Biscay and areas to the north of 48 N cannot be carried out at present. If such an exercise were to be attempted in the future, a consideration of stock structure must be taken into account. 6WRFNDQGUHFUXLWPHQWUHODWLRQVKLSDQGELRORJLFDOUHIHUHQFHSRLQWV The Group was asked to consider what is the most appropriate stock and recruitment relationship for the northern hake stock, with a view to carrying out medium term predictions of yield and SSB as part of the simulation studies (Section 9) and with which to set biological reference points in relation to harvest control rules. Since the Group has accepted the current 22

26 ICES assessment with which to begin predictions and simulations of the effect of measures introduced under the hake recovery plan, it does not at this time consider it necessary to review the S/R relationship nor the values for biological reference points. 'LVDJJUHJDWLRQRIWKHDVVHVVPHQWGDWDLQWRIOHHWVRUPpWLHUVZLWKZKLFKWRSHUIRUP VLPXODWLRQVWXGLHVRIWKHHIIHFWVRIWHFKQLFDOPHDVXUHVDLPHGDWSURWHFWLQJMXYHQLOH KDNH In order to carry out simulations by fishery units (FU), the annual length distributions of catches (landings and discards) have been converted by FU into ages for the period The first step was to raise all these length compositions with the international weight/length relationship and to correct SOP discrepancies between countries, since each country involved has applied their own parameters. The effect of this is that the sum of the catches at age obtained by year is not exactly the same as the international catches at age used by ICES SSDS, because a different raising procedure is carried out, but it is satisfactory for simulation purposes in terms of relative importance of each age and FU. The next step was to convert these length compositions into ages, applying the combined annual ALK (France plus Spain) to obtain numbers and weight at age (landings and discards), and then sum up to the final catch at age by year. In the case of French distribution of discards in 1999, it was split into relevant FUs using the average contribution of each in Finally, the proportion of numbers by FU at age was compared to the whole international catch at age matrix, which can be used to see, for instance, the relative contribution to the total exploitation pattern of each FU. These proportions have been derived from the average matrix for the period considered (see Table 8.1). 'LVFDUGGDWD Annual estimates of hake discards in the fleets operating in Sub-area VIII are obtained by fitting length distributions in French survey catches to those in commercial landings (using similar mesh sizes). These are used in the ICES assessment, which does not include discard data for hake catches in Sub-area VII or further north. Discard data sets for most of the fleet units catching hake are available from on-board sampling projects carried out over recent years with EU support (see Table 8.2), but they are not used in the assessment due to short time series or sporadic sampling. A review of the available discard data was carried out by the ICES Study Group on Discard and By-Catch Information in 2000 (ICES, 2000). A further review will be carried out by the same Study Group in March The available discard data can be used to indicate where technical measures may be most beneficial by pinpointing key areas where high discards of juveniles hake. They may be also be included in future assessments and used to evaluate the need for and benefits of technical measures aimed at protecting juvenile hake by improving the exploitation pattern (see Section 10.5). 23

27 Table 8.1- Percentage (C a,fu /Sum a, ) from Mean Catch matrix for $*( )8B )8B )8B )8B )8B )8B )8B )8B )8B )8B )8B )8B )8B )8B )8B 7RWDO 7RWDO 24

28 Table 8.2 Description of hake discard data available per fishing unit. Countries Spain France Fishing Units Sampling Sampling Assessment Years Fishing Main Gears Trips 4 On-board Bottom trawl No On-board Long line No 14 On-board Bottom trawl No 4, 5, 8 On-board Samples collected Bottom Trawl No Bay Survey RESSGASC (indirect discards by comparing with NA Bottom Trawl 9, 10, 15 Biscay landings length frequencies) Ireland 15, 16 On-board Otter board trawl, beam trawl, Scottish seine, gillnets No UK (E+W) On-board NA NA 26 NA White fish otter trawl Beam trawl Nephrops trawl and semi pelagic trawl UK 16 On-board NA Otter bottom trawl No (Scot.) UK (NI) 16 On-board NA Semi-pelagic trawl and Nephrops trawl No Denmark 16 On-board NA Gillnets No NA = Not available No 25

29 $VFKHGXOHRIPRGHOOLQJZRUNLQFOXGLQJDUHYLHZRIWKHELRORJLFDOUHIHUHQFHSRLQWV WREHFRPSOHWHGIRUWKH67(&)SOHQDU\PHHWLQJWK$SULO The modeling work required to advise the Hake Recovery Plan relates to two phases; the recovery phase until the end of 2006 and the post-recovery phase. For the recovery phase, it will be necessary to carry out deterministic simulations with annual predictions, and with recruitment set at various levels between the long-term mean in the assessment and something below the recent historic low. A stochastic stock/recruitment relationship (with no correlation and a strong correlation between successive years) should be used for the post-recovery phase, for which an output of statistical averages will be adequate. Preliminary simulation work will be required, initially at the stock level, but later disaggregated by fleet, resulting in the production of isopleths of YPR (by weight and value) and SPR plotted on axes of F multiplier by size range. This will provide a basis for selection of relevant combinations of F multiplies and size ranges to be investigated in the other simulations and provide evidence for the selection of appropriate F targets. The simulation scenarios will commence from the start of 2002 and use a combination of Fs on four size ranges: <27 cm, small juveniles ; cm (or whichever size corresponds to L 25 of a 100 mm mesh in otter trawls), mid-juveniles ; cm (or whichever size corresponds to L 50 of the female maturity ogive), sub-adults ; and >50 cm, adults. Fishing pattern hypotheses in relation to Fsq during the recovery period are to include F multipliers of 0 and 0.5 on the small juveniles; 0.5 and 1.0 on the second category; 0.5,0.75 and 1.0 on the sub adults and 0.75 and 1.0 on the adults, in addition to a status quo F scenario for all sizes. The first priority for this work is to use the whole assessment to give indicative results of these simulations which will be discussed at a meeting held by the Commission in Brussels early in March A meeting of national scientists may be required prior to this meeting. Following this, the most useful scenarios will be used in stochastic simulations and with fleet disaggregated data, and plans made for carrying out long-term simulations including an economic analysis of the results. This work will be more clearly defined within the research plan resulting from the April STECF meeting. It will be important to revisit the F reference points within the precautionary approach as a basis for the HRP. Various harvesting rules need to be evaluated within a stochastic framework in order to arrive at decisions for TACs consistent with achieving the HRP s targets, which should nevertheless take account of previous the year s TAC and the estimated SSB. A harvest control law such as: TAC=f(SSB,F) and the TAC does not vary by more than 15% year on year. The aim is to avoid unnecessary closing and opening of the hake fishery. Whether the results of this work will be available for the April 2001 STECF meeting depends chiefly on the availability of suitable software (and the knowledge of how to use it convincingly). 3RVVLEOH5HVHDUFK$UHDVWREHLQFOXGHGLQDKDNHVWRFNUHFRYHU\SODQ The Group discussed with the Commission (AL) possible research areas aimed at improving knowledge of the hake and its fishery in the context of the hake recovery plan. The Commission put a low priority on studies that would be of little or no importance to the hake 26

30 recovery plan, and the various topics were discussed in terms of results that could be available for February 2001(as input into Commission Decision Emergency Measures ) April 2001 (as input into Recovery Plan) Longer term topics that could be used to adjust the Recovery Plan and, improve assessments. 6SDZQLQJ$UHDV A study has just been completed on the egg/larval distributions of hake from the 1998 international mackerel egg survey, though data are available from 1983 onwards. These maps are presented in this report and are therefore available for February. The Commission otherwise regards this topic as medium priority, since the protection of spawning hake is unlikely to be a major component of the recovery plan. The possibility of collecting data on hake reproductive biology and population structure as part of a hake egg production project needs to be further considered in context of using samples from the 2001 mackerel egg surveys. 1XUVHU\$UHDV The Commission regards this topic of crucial importance in both the short and longer term. Data from all available surveys, including those in Sub Areas VI, IV and III, should be merged and mapped to identify important nursery areas, and could be available for April to identify candidate areas for control measures (e.g. closures). In order to advise on the duration of any possible closures, monthly monitoring of catches would be required for these nursery areas. It may also be possible to use logbook data to provide real time information on catches and to collect information from fishermen on the distribution of nursery areas %LRORJLFDO3DUDPHWHUV The Group agreed that an appropriate and up-to-date maturity ogives for the whole population was important and that we need to look at data from different areas, though it was unnecessary for ogives to be constantly updated. Fecundity estimates will only be important if the egg production method is used to assess hake (see Spawning Areas). The benefit of all laboratories giving priority to a particular species in a major project over a given period (as adopted historically by ICCAT) was discussed. $JH(VWLPDWLRQ This was considered of crucial importance, but results will only be achieved on a medium to long term time scale. The Commission proposed an examination of hake ALKs in relation to areas and sex, and that a small scale pilot study would be useful to check if a split sex assessment is a major benefit (though data by sex are not available for the majority of landings) and hence whether further work is required. The Group agreed that more ageing data are required for areas outside VIII, and particularly in VII. 'LVFDUGV Better discard data are required for all the main métiers in order to evaluate the magnitude of the problem of mortality on juvenile hake in various fisheries. The Commission also sees the monitoring of discards in hake and cod fisheries as a high priority in relation to monitoring 27

31 the progress of the recovery plans. Discards are an important part of the new Directive on Sampling, and it is important that national laboratories monitor discards in their fisheries. 7HFKQLFDO&RQVHUYDWLRQ0HDVXUHV This topic has a high priority and work is needed with the industry. The Commission will be holding a meeting in February where gear technologists will discuss various TCM in relation to cod and hake, particularly in relation to selectivity. Input from economists is required in order to look at the short term costs to fishermen. 6LPXODWLRQ:RUN See Section 9. Also note the requirement for investigations into improved assessment and management measures 6WRFN6WUXFWXUH This is regarded as a high priority by commission, particularly if separate assessments of hake in areas VII and VIII show differences. The Commission advised the Group to look at all possible tools for stock structure in the context of a 5 th Framework Project. The importance of environmental factors in stock dynamics and distribution should also be addressed, including the likelihood of such issues as pollution effecting hake population decline. (FRQRPLFV The Commission advised that the simulation work should be carried out in terms of yield in Euros and tonnes. It is important to be able to simulate tie-up days and their economic impact on fleets. 7KH)LVKHU\ In addition to the need for better information on fleet structure and the relationship between fleet units and hake exploitation patterns, the Commission regard a review of vessel efficiency as important, which implies that national data should be presented to a common standard. $VVHVVPHQWV Work is needed to improve the assessment of hake stocks, including fisher-independent indices of SSB (in addition to egg production methods) and accurate effort data for standardisation of tuning fleets. 5HIHUHQFHV ICES, Report of the ICES Working Group on Fisheries Units in Sub-areas VII and VII. ICES CM, 1991/Assess:24. ICES, Report of the Study Group on Discard and By-catch information, March ICES CM 2000/ACFM:11. ICES, Report of the Working Group on the Assessment of Southern Shelf Demersal Stocks, 4-13 September ICES CM 2001/ACFM:05, 773 pp. 28

32 APPENDIX I Hake juveniles and adults distribution

33 A1-1

34 A1-2

35 A1-3

36 A1-4

37 A1-5

38 A1-6

39 º 8º 7º 6º 5º 4º 3º 2º 1º 0º 52º 52º 51º 51º 50º 50º 49º 49º 48º º 47º 47º 46º 46º 45º 45º 44º 44º 43º 43º 42º 41º 40º +$.( 5HFUXLWPHQW $XWXPQ Age 0 number / hour º 41º 40º 39º SESITS project 39º 38º 38º 37º 37º 36º º 8º 7º 6º 5º 4º 3º 2º 1º 0º 36º Fig. 4Hake recruitment (standardised age 0 number/hour) in A1-7

40 º 8º 7º 6º 5º 4º 3º 2º 1º 0º 52º 52º 51º 51º 50º 50º 49º 49º 48º º 47º 47º 46º 46º 45º 45º 44º 44º 43º 43º 42º 41º 40º +$.( 5HFUXLWPHQW $XWXPQ Age 0 number / hour º 41º 40º 39º SESITS project data 39º 38º 38º 37º 37º 36º º 8º 7º 6º 5º 4º 3º 2º 1º 0º 36º Fig. 5 Hake recruitment (standardised age 0 number/hour) in A1-8

41 A1-9

42 A1-10

43 A1-11

44 A1-12

45 A1-13

46 A1-14

47 A1-15

48 Fig. 11 Distribution of age 0 hake in A1-16

49 Fig. 12 Distribution of age 0 hake in A1-17

50 Fig. 13 Distribution of age 0 hake in A1-18

51 Fig. 14 Distribution of age 0 hake in A1-19

52 , 9, ,, 9,, 9,, ,, Legend Nos/30 min To >2+ 9,, 9,, ,, ' ' ' ' ' ' ' ' ( ( ( ( ( ( ( ( 9,, 9,, 48 Fig 15 Abundance indices of juvenile hake in November A1-20

53 6XUYH\&DWFKHVRI+DNHLQ1RYHPEHU ,E 9,D ,,F 9,,E 9,,D ,,N Legend Nos/30 min Tow >2+ 9,,J 9,,I ,,H 9,,K 9,,M ' ' ' ' ' ' ' ' ( ( ( ( ( ( ( ( 48 Fig 16 Abundance indices of juvenile hake in November A1-21

54 6XUYH\&DWFKHVRI+DNHLQ1RYHPEHU ,E 9,D ,,F 9,,E 9,,D ,,N Legend Nos/30 min Tow 9,,J 9,,I > ,,H 9,,K 9,,M ' ' ' ' ' ' ' ' ( ( ( ( ( ( ( ( 48 Fig 17 Abundance indices of juvenile hake in November A1-22

55 6XUYH\&DWFKHVRI+DNHLQ1RYHPEHU ,E 9,D ,,F 9,,E 9,,D ,,N Legend Nos/30 min Tow >2+ 9,,J 9,,I ,,H 9,,K 9,,M ' ' ' ' ' ' ' ' ( ( ( ( ( ( ( ( 48 Fig 18 Abundance indices of juvenile hake in November A1-23

56 A1-24 Fig. 19 Distribution and abundance of 0PHUOXFFLXVeggs/m² for 1998 (Alvarez et al., 2000). 0$5&+ 0$;ÃHJJVPð 0PHUOXFFLXV (JJÃDEXQGDQFHPð $35,/0$< 0$;ÃHJJVPð 0PHUOXFFLXV (JJVÃDEXQGDQFHPð 0$<-81( 0$;ÃHJJVPð 0PHUOXFFLXV (JJÃDEXQGDQFHPð -81(-8/< 0$;ÃHJJVPð 0PHUOXFFLXV (JJÃDEXQGDQFHPð

57 A1-25 Fig. 20 Distribution and abundance of 0PHUOXFFLXVlarvae/m² for 1998 (Alvarez et al., 2000) $35,/0$< 0$;ÃODUYDHPð 0PHUOXFFLXV /DUYDÃDEXQGDQFHPð -81(-8/< 0$;ÃODUYDHPð 0HUOXFFLXV /DUYDÃDEXQGDQFHPð 0$<-81( 0$;ÃODUYDHPð 0PHUOXFFLXV /DUYDÃDEXQGDQFHPð 0$5&+ 0$;ÃODUYDHPð 0PHUOXFFLXV /DUYDÃDEXQGDQFHPð

58 $33(1',;,, 'LVWULEXWLRQRIFDWFKHVE\QDWLRQDOIOHHWV

59 'HVFULSWLRQRIILVKHU\XQLWVDQG&RXQWU\SHUFHQWDJHRIQRUWKHUQKDNHFDWFKHVE\&RXQWU\ DQGILVKHU\XQLWVLQDQG $UHD )LVKLQJXQLW &RXQWU\ &RXQWU\ SHUFHQW )LVKHU\ XQLWV SHUFHQW &RXQWU\ SHUFHQW )LVKHU\ XQLWV SHUFHQW VIIe-k 1 Long line in SPAIN medium to deep water UK(E+W) 5 1 VIIe-k 2 Long line in FRANCE shallow water VIIe-k 3 Gill net SPAIN 45 FRANCE 6 25 UK(E+W) VIIe-k 4 Non-Nephrops SPAIN trawling in medium to deep FRANCE 4 8 water UK(E+W) IRELAND 11 UK(Scot) 0 VIIe-k 5 Non-Nephrops FRANCE trawling in shallow water UK(E+W) IRELAND 72 UK(Scot) 3 VIIe-k 6 Beam trawling UK(E+W) in shallow VIIe-k water (B/T) 7+8 Nephrops FRANCE trawling in mediun to deep UK(Scot) 0 water VIIIabd 9 Nephrops FRANCE trawling in shallow to medium water VIIIabd 10 Trawling in FRANCE shallow to medium water VIIIabd 12 Long line in SPAIN deep and medium water FRANCE 6 VIIIabd 13 Gill nets in SPAIN 49 medium to shallow water FRANCE VIIIabd 14 Trawling in SPAIN deep and medium depth A2-1

60 VIIe-k VIIIabd IIIa IVa,b VI VIIa,d 15 Miscellaneous 16 Outsiders FRANCE IRELAND 69 UK(Scot) 1 NETHERLAN 0 D BELGIUM 1 1 OTHERS 0 SPAIN 10 8 FRANCE 5 7 UK(E+W) 10 4 IRELAND 4 7 UK(Scot) NETHERLAN 1 3 D BELGIUM 1 1 DENMARK NORWAY 6 7 OTHERS Unknown FRANCE RWDO ODQGLQJV W IURPDOODUHDV A2-2

61 6XEDUHD9,, /HQJWKGLVWULEXWLRQ)LVKHU\XQLW /HQJWKGLVWULEXWLRQ)LVKHU\XQLW Numbers ( 000) Numbers ( 000) Length (cm) Length (cm) /HQJWKGLVWULEXWLRQ)LVKHU\XQLW /HQJWKGLVWULEXWLRQ)LVKHU\XQLW Numbers ( 000) 2000 Numbers ( 000) Length (cm) Length (cm) A2-3

62 'LYLVLRQV9,,,DEG /HQJWKÃGLVWULEXWLRQÃ)LVKHU\ÃXQLWÃ /HQJWKÃGLVWULEXWLRQÃ)LVKHU\ÃXQLWÃ Numbers ( 000) 400 Numbers ( 000) Length (cm) Length (cm) /HQJWKÃGLVWULEXWLRQÃ)LVKHU\ÃXQLWÃ /HQJWKÃGLVWULEXWLRQÃ)LVKHU\ÃXQLWÃ Number ( 000) 100 Numbers ( 000) Length (cm) Length (cm) /HQJWKÃGLVWULEXWLRQÃ)LVKHU\ÃXQLWÃ Numbers ( 000) Length (cm) A2-4

63 6SDQLVKODQGLQJVE\JHDU6XEDUHD9, Gillnet Long line Trawl 800 7RQQHV \HDUV A2-5

64 6SDQLVKODQGLQJVE\JHDU6XEDUHD9,, 7RQQHV \HDUV Gillnet Long line Pair trawl Bou trawl Baca trawl A2-6

65 7RQQHV SDQLVKODQGLQJVE\JHDU'LYLVLRQ9,,,DE \HDUV Gillnet Long line Pair trawl Bou trawl Baca trawl A2-7

66 A2-8

67 A2-9

68 A2-10

69 A2-11

70 8. ODQGLQJV E\ ILVKHU\ XQLW LQ )LVKHU\XQLW *HDU 'HSWK /DQGLQJVW E&W NI Scot IV Scot VI Longline M &D 83,8 Longline S 0,1 Gill net 1210,5 Trawl M &D 1698,9 Trawl S 35,5 Beam S & M 53,4 Beam 18,5 Longline 37,2 Gill net 15,3 Trawl 58,9 66 Heavy trawl Light & Nephrops trawl Seine Other Midwater-trawl 382 Twin-trawl 48 Nephrops 111 7RWDO Note. Scottish landings derived from numbers and l/w relationship A2-12

71 +DNHODQGLQJVDOOJHDUVE\TXDUWHUDQGUHFWDQJOHLQ ,E 9,D HAKE Landings (t) 9,,F Q1 Q2 Q3 Q4 9,,E 9,,D ,,N 9,,J 9,,I 50 9,,H 9,,K 9,,M ' ' ' ' ' ' ' ' ( ( ( ( ( ( ( ( 48 A2-13