WGEF Report 2005

ICES WGEF Report 2005

ICES Advisory Committee on fishery Management ICES CM 2006/ACFM:03 Ref. G

Report of the Working Group on Elasmobranch Fishes (WGEF)

14–21 June 2005 Lisbon, Portugal

International Council for the Exploration of the Sea Conseil International pour l’Exploration de la Mer H.C. Andersens Boulevard 44-46 DK-1553 Copenhagen V Denmark Telephone (+45) 33 38 67 00 Telefax (+45) 33 93 42 15 www.ices.dk [email protected]

Recommended format for purposes of citation: ICES. 2006. Report of the Working Group on Elasmobranch Fishes (WGEF), 14–21 June 2005, Lisbon, Portugal. ICES CM 2006/ACFM:03. 232 pp.

For permission to reproduce material from this publication, please apply to the General Secretary.

The document is a report of an Expert Group under the auspices of the International Council for the Exploration of the Sea and does not necessarily represent the views of the Council.

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Contents

1 Introduction ...... 1 1.1 Terms of Reference ...... 1 1.2 Participants ...... 1 1.3 Background...... 1 1.4 Current projects of relevance to the WG ...... 2 1.4.1 Working Group on Fish Ecology...... 2 1.4.2 International Symposium on Dogfish Management ...... 2 1.4.3 Theme Session on Elasmobranch Fisheries Science, 2005...... 3 1.4.4 Study Group on Age Length Structured Assessment Models...... 3 1.4.5 International Bottom Trawl Survey Working Group...... 3 1.5 Commercial catch data ...... 3 1.6 Discards data for elasmobranch fishes...... 5 1.7 Methods used...... 6 1.8 Ecosystem considerations...... 6 1.9 Recommendations ...... 7

2 Spurdog in the North East Atlantic...... 10 2.1 The Fishery...... 10 2.2 Biological composition of the catch ...... 12 2.2.1 Catch in numbers ...... 12 2.2.2 Quality of catch and biological data ...... 12 2.2.3 By-catch and discards information ...... 12 2.3 Fishery-independent information...... 12 2.3.1 Groundfish surveys...... 12 2.4 Mean length, weight, maturity and natural mortality-at-age ...... 13 2.5 Recruitment ...... 13 2.6 Stock assessment ...... 13 2.6.1 Previous studies ...... 13 2.6.2 Data exploration and preliminary modelling ...... 14 2.6.3 Stock assessment ...... 15 2.7 Simulation of effects of maximum landing size regulations...... 15 2.7.1 Methods ...... 15 2.7.2 Results ...... 17 2.8 Reference points ...... 17 2.9 Quality of the assessment ...... 17 2.10 Pupping and juvenile fishing area closures...... 17 2.11 Management considerations ...... 17

3 Deep-water sharks in the North East Atlantic (ICES Areas I–XIV)...... 30 3.1 The fishery...... 31 3.1.1 Advice and management applicable to 2005 and 2006...... 31 3.1.2 The fishery...... 31 3.2 Biological composition of the catch ...... 33 3.2.1 Quality of catch and biological data ...... 33 3.2.2 Length and age frequencies ...... 35 3.3 Fishery-independent information...... 36 3.4 Catch per unit of effort ...... 36 ii | ICES WGEF 2005 Report

3.4.1 Discards ...... 39 3.5 Mean length, weight, maturity, natural mortality and recruitment ...... 40 3.5.1 Leaf scale gulper shark ...... 40 3.5.2 Portuguese dogfish...... 41 3.6 Stock assessment ...... 41 3.6.1 Previous assessments of stock status ...... 41 3.7 Reference points ...... 42 3.8 Quality of the assessment ...... 42 3.9 Management considerations ...... 42

4 Other deepwater sharks from the northeast Atlantic (ICES Subareas IV–XIV) ...... 56 4.1 The fishery...... 56 4.1.1 Advice and management applicable ...... 56 4.1.2 Description of the fishery ...... 56 4.2 Biological composition of the catch ...... 57 4.3 Fishery-independent information...... 59 4.4 Catch per unit of effort ...... 59 4.5 Discards ...... 59 4.6 Mean length, weight, age, maturity, natural mortality...... 59 4.7 Stock assessment ...... 59 4.8 Stock status...... 60 4.9 Reference points ...... 60 4.10 Quality of the assessment ...... 60 4.11 Management considerations ...... 60

5 Kitefin shark (entire ICES area) ...... 62 5.1 The fishery...... 62 5.1.1 Advice and management applicable to 2003 and 2004...... 62 5.1.2 The fishery in 2004...... 62 5.2 Biological composition of the landings ...... 62 5.2.1 Catch in numbers ...... 62 5.2.2 Quality of catch and biological data ...... 62 5.3 Fishery-independent information...... 63 5.4 Mean length, weight, maturity and natural mortality-at-age ...... 63 5.5 Recruitment ...... 63 5.6 Stock assessment ...... 63 5.6.1 Previous assessments of stock status ...... 63 5.6.2 Data exploration and preliminary modelling ...... 63 5.6.3 Stock Assessment ...... 63 5.7 Stock and catch projection...... 64 5.8 Reference points ...... 64 5.9 Quality of the assessment ...... 65 5.10 Management considerations ...... 65

6 Porbeagle in the North East Atlantic (Sub-areas I-XIV) ...... 73 6.1 The Fishery...... 73 6.2 Biological composition of the Catch ...... 77 6.3 Management considerations ...... 77

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7 Basking Shark in the northeast Atlantic (ICES Areas I-XIV)...... 79 7.1 The fishery...... 79 7.1.1 Advice and management applicable ...... 79 7.1.2 The fishery...... 79 7.1.3 The fishery 2001–2004 ...... 79 7.2 Biological composition of landings ...... 80 7.3 Fishery-independent information...... 80 7.4 Catch per unit of effort ...... 80 7.5 Discards ...... 80 7.6 Management considerations ...... 80

8 Demersal elasmobranchs in the Barents Sea...... 83 8.1 The fishery...... 83 8.1.1 Advice and management applicable to 2003 and 2004...... 83 8.1.2 The fishery in 2004...... 83 8.2 Fishery-independent information...... 84 8.2.1 Groundfish surveys...... 84 8.3 Mean length, weight, maturity and natural mortality-at-age ...... 84 8.4 Spawning and juvenile fishing area closures...... 84 8.5 Management considerations ...... 85 8.6 Tables and figures...... 86

9 Demersal Elasmobranchs in The Norwegian Sea ...... 95 9.1 The Fishery...... 95 9.1.1 Advice and management applicable to 2003 and 2004...... 95 9.1.2 The fishery in 2004...... 95 9.2 Management considerations ...... 95

10 Demersal elasmobranchs in the North Sea, Skagerrak, Kattegat and Eastern Channel...... 97 10.1 Introduction ...... 97 10.2 Eco-region and stock boundaries...... 97 10.3 The fishery...... 97 10.3.1 Description of the fishery ...... 97 10.3.2 Advice and management applicable to 2003 and 2004...... 97 10.4 Biological composition of the catch ...... 98 10.4.1 Catch data skates and rays ...... 98 10.4.2 Catch data demersal sharks...... 98 10.5 Fishery-independent information...... 98 10.5.1 Skates and rays ...... 99 10.5.2 GIS analysis of IBTS data ...... 99 10.5.3 Demersal sharks...... 100 10.6 Mean length, weight, maturity and natural mortality-at-age ...... 100 10.7 Recruitment ...... 101 10.8 Stock assessment of Raja clavata...... 101 10.8.1 Data exploration...... 101 10.8.2 GLM model of survey abundance by length class...... 102 10.8.3 Discussion...... 103 10.8.4 Conclusions on stock status ...... 104 10.8.5 Management considerations ...... 104

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11 Demersal Elasmobranchs at Iceland and East Greenland...... 133 11.1 The Fishery...... 133 11.1.1 The fishery in 2004...... 133 11.2 Management Considerations ...... 133

12 Demersal elasmobranchs at the Faroe Islands...... 136 12.1 The fishery...... 136 12.1.1 Advice and management applicable to 2003 and 2004...... 136 12.1.2 The fishery up to 2004...... 136 12.2 Biological composition of the catch ...... 136 12.3 Fishery-independent information...... 136 12.4 Management considerations ...... 136

13 Demersal elasmobranchs in the Celtic Seas (ICES Divisions VI & VII (Except Area VIId)) 139 13.1 The fishery...... 140 13.1.1 Advice and management applicable to 2003 and 2004...... 140 13.1.2 The fishery in 2004...... 140 13.2 Biological composition of the catch ...... 141 13.2.1 Rays and skates...... 141 13.2.2 Demersal sharks...... 141 13.3 Quality of catch and biological data ...... 141 13.3.1 Effort data...... 142 13.4 Fishery-independent information...... 142 13.4.1 Groundfish surveys...... 142 13.5 Mean length, weight, maturity and natural mortality-at-age ...... 143 13.6 Recruitment ...... 143 13.7 Stock assessment ...... 143 13.8 Stock and catch projection...... 143 13.9 Reference points ...... 143 13.10 Quality of the Assessment ...... 143 13.11 Spawning and Juvenile fishing area closures...... 143 13.12 Management considerations ...... 144

14 Demersal elasmobranchs in the Bay of Biscay and Iberian Waters (ICES Subarea VIII and Division IXa) ...... 155 14.1 The fishery...... 155 14.1.1 Landings data...... 157 14.1.2 Advice and management...... 157 14.2 Biological information...... 157 14.2.1 Length frequencies...... 157 14.2.2 Tagging data and biometric relationships ...... 158 14.2.3 Surveys ...... 159 14.2.4 Landings per unit of effort...... 159 14.2.5 Discards ...... 159 14.2.6 Growth parameters...... 159 14.3 Stock assessment ...... 160 14.3.1 Previous assessments ...... 160 14.4 Management considerations ...... 160

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15 Demersal elasmobranchs in the Azores and Mid-Atlantic Ridge...... 175 15.1 The fishery...... 175 15.1.1 Advice and management applicable to 2003 and 2004...... 175 15.1.2 The fishery in 2004...... 175 15.2 Biological composition of the Landings...... 176 15.3 Fishery-independent information...... 176 15.4 Discards ...... 176 15.5 Mean length, weight, maturity and natural mortality-at-age ...... 177 15.6 Management considerations ...... 177

16 Other pelagic species from the northeast Atlantic (ICES Subareas I–XIV)...... 183 16.1 Advice and management applicable ...... 183 16.2 The fishery...... 183 16.3 Biological composition of the landings ...... 184 16.4 Catch data ...... 184

17 Elasmobranch NEI landings in ICES area (I–XIV) ...... 189 17.1 Outline of the work...... 189 17.2 Data source ...... 189 17.3 Results and discussion...... 190 17.3.1 Identification of existent elasmobranch fishes NEI categories ...... 190 17.3.2 Elasmobranch species identified in the landings ...... 191 17.3.3 Temporal variation of elasmobranchs NEI landing statistics...... 199 17.3.4 Correlation analysis ...... 205 17.3.5 Cluster analysis results and discussion ...... 209

18 References ...... 210

Annex 1: Participants list...... 218

Annex 2: Technical minutes...... 220

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1 Introduction

1.1 Terms of Reference

The Working Group Elasmobranch Fishes [WGEF] (Chair: Maurice Clarke, Ireland) will meet in Lisbon, Portugal, from 14–21 June 2005, to: a ) update the description of elasmobranch fisheries (including those on deep-water sharks) in the ICES area and compile landings and discard statistics by ICES Subarea and Division; b ) Conduct and report on investigations of spatial dynamics of survey data for shelf- based species and investigate data from IBTS and other surveys; c ) continue preparations to summarise status and changes in elasmobranch fish species distribution in the North Sea for the period 2000–2004, for input to the Regional Ecosystem Study Group for the North Sea in 2006; d ) Start the process of making assessments of spurdog, skates and rays, lesser spotted dogfish, deepwater sharks and porbeagle.

WGEF will report to ACFM by 15 August 2005 and make its report available for the attention of ACFM and the Living Resources Committee.

1.2 Participants Tom Blasdale UK Maurice Clarke (Chair) Ireland José De Oliveira UK (England and Wales) Guzman Diez Spain (Basque Country) Helen Dobby UK (Scotland) Jim Ellis UK (England and Wales) Ivone Figueiredo Portugal Nils-Roar Hariede Norway Henk Heessen The Netherlands Boris Frentzel-Beyme Germany Graham Johnston Ireland Dave Kulka Canada Pedro Machado Portugal Mario Pinho Portugal (Azores) Charlott Stenberg Sweden (Part-time)

1.3 Background

The Study Group on Elasmobranch Fishes (SGEF), having been established in 1989, was re- established in 1995 and had meetings in that year, 1997 and 1999. Assessment of elasmobranch species had proved very difficult owing to lack of data. The 1999 meeting was held concurrently with the EC-funded Concerted Action Project meeting (FAIR CT98-4156) allowing for a greater participation from various institutes around Europe. The next meeting of the group was in 2002, where assessments were carried out for the first time. Assessments were attempted for 8 of the 9 case study species considered by the EC-funded DELASS Contract (CT99-055). The success of this meeting was due to the DELASS project, a three- year collaborative effort involving fifteen fisheries research institutes and two sub-contractors. The large participation of DELASS scientists at the 2002 meeting was of great importance.

In 2002, SGEF recommended the group be continued as a Working Group. The medium-term remit of this WG being to adopt and extend the methodologies and assessments for 2 | ICES WGEF Report 2005

elasmobranchs prepared by the EC-funded DELASS project; to review and define data requirements (fishery, survey and biological parameters) in relation to the needs of these analytical models and stock identity; and to carry out such assessments as are required by ICES’ customers. In 2003, the first meeting of this group would review the final DELASS report, consider national and international sampling schemes, including those carried out under the EU Data Collection Regulation, and report to PGCCDBS, and make arrangements to carry out assessments for such elasmobranch stocks.

In 2003, WGEF met in Vigo, Spain and worked to further the stock assessment work carried out under DELASS. In 2003, landings data were collated for the first time. This exercise was based on data from the FAO FISHSTAT database, data from national scientists and other data submitted to ICES.

In 2004, WGEF worked by correspondence to collate and refine catch statistics for all elasmobranchs in the ICES area. This task is complicated by the use, by many countries, of generic reporting categories for sharks, rays and dogfishes. There is now considerable expertise in the application of relevant assessment methods to elasmobranchs. However the success of assessments is precluded by the continuing lack of even the most basic input data, including catch information. An important task of WGEF is to evaluate sampling plans and their usefulness for providing assessment data.

In 2005, WGEF came under ACFM and was given the task of supporting the advisory process. This was because ICES has been asked by the European Commission to provide advice on certain species. This task was partly achieved by WGEF in that preliminary assessments have been provided for spurdog, kitefin shark, thornback ray (North Sea) and deepwater sharks (combined).

Stock assessment of deepwater sharks and of pelagic sharks is particularly difficult owing to lack of species-specific catch data and the straddling and/or highly migratory nature of these stocks. In 2004, the International Commission for the Conservation of Atlantic Tunas convened a working group to assess the status of two pelagic species, blue and shortfin mako shark. These are trans-North Atlantic stocks and ICES is unable to conduct any meaningful stock assessments. WGEF will maintain close collaboration with WGDEEP to refine catch and effort data and to support the advisory process.

1.4 Current projects of relevance to the WG

1.4.1 Working Group on Fish Ecology

The Working Group on Fish Ecology has undertaken several studies of relevance to WGEF. During the 2005 meeting, WGFE had the TOR to “explore the feasibility of estimating gear- specific catchability for various species of skates, rays, and sharks in the North Sea, and to use the results to provide estimates of maximum gear-specific effort levels that can be exerted without exceeding the sustainable mortality rates for those species or species groups”. Preliminary studies were undertaken, though WGFE considered that more data were required to fully address the TOR. More data on the catches, discards and survivorship of elasmobranchs from mixed trawl fisheries (where some elasmobranchs are important by-catch species), and gillnet and long line fisheries (in which elasmobranchs are either a target species or by-catch) are required (ICES, 2005c: Section 5). WGFE also examined the relative catchability of fishes, including the effects of fish size, in survey gears, and this work included case studies examining the relative catchability of rajids (ICES, 2005c: Section 6).

1.4.2 International Symposium on Dogfish Management

In June 2005, the ‘First International Symposium on the Management and Biology of Dogfish Sharks’ was held in Seattle, USA. The presentations given at the symposium covered a wide

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range of topics, but focused mainly on fisheries, biology, age and tagging studies, as well as modelling and management issues. The meeting highlighted that management for this species is needed in many areas where exploitation occurs, including the NW and NE Atlantic and NE Pacific.

1.4.3 Theme Session on Elasmobranch Fisheries Science, 2005

In order to facilitate ICES’ goals in the science of elasmobranch fisheries, it was agreed to have a Theme Session at the 2005 ASC (20–24 September) to provide a forum for researchers to exchange information and pool scientific experience of these data-deficient stocks in the ICES and other areas. Basic biological studies (e.g. growth, mortality, and reproduction) are important topics, especially when there is emphasis on how such data can improve traditional and novel assessment methods. Assessment methodologies, for fisheries assessment and vulnerability status, will be important topics, along with information on stock structure and migrations

1.4.4 Study Group on Age Length Structured Assessment Models The Study Group on Age-Length Structured Assessment Models met for the second time in March 2005. SGASAM consider it important to include length-structure in cases when it is thought such models provide a better description of the fishery and biological processes, and also when problems with age determination do not permit the use of age-structured models or make such models less reliable. A number of length- and age-length-structured assessment tools are being developed and were presented at this meeting with the ability to make use of a wide range of commercial and auxiliary fishery independent data. Such novel assessment methods may be appropriate for elasmobranch stocks. A proposed TOR for the next meeting of SGASAM is to ‘evaluate the use of age-length structured models for the assessment of stocks for which age- disaggregated data are sparse or unreliable (e.g. Nephrops, elasmobranchs, hake, anglerfish redfish).’

1.4.5 International Bottom Trawl Survey Working Group

Given that survey data are likely to be one of the more important sources of species-specific data for this group of elasmobranchs, it is recommended that WGEF liase with the International Bottom Trawl Survey Working Group. Data for the more common elasmobranch species encountered in the internationally-coordinated surveys in the North Sea and Skagerrak have been examined (see Section 10). It is recommended that IBTSWG should be asked to examine data from the North Sea and Skagerrak region that is held in the DATRAS database and (a) identify and where possible correct erroneous data (e.g. species mis-identifications), (b) examine the length distributions (by sex) of all elasmobranch species and, (c) identify the core areas where the various species are routinely encountered so that trends in the relative abundance of demersal elasmobranchs can be examined on the appropriate spatial scale.

In future years, it is hoped that data from the IBTS surveys in southern and western waters will provide appropriate fishery-independent survey data for various demersal elasmobranchs in the Celtic Seas, and Biscay and Iberian regions. With regards to the southern and western IBTS surveys it is recommended that IBTSWG identify which elasmobranchs are recorded in the surveys and illustrate the overall distributions of these species in the surveys.

1.5 Commercial catch data

Most countries that participate in the group have provided catch data. Several important fishing nations with elasmobranch catches are not represented at the group.

The absence of detailed landings data from France, Norway and Spain, for some fisheries, is a cause for concern. Many countries have not provided length compositions of their catches, in 2005, but in 2006 WGEF intends to collate such data.

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Table 1.1 presents available landings data from the FISHSTAT database for the ICES area Cumulative reported landings amount to over 5 million tonnes, with about 2.5 million tonnes having been reported in generic or “NEI” (not elsewhere identified categories). For WGEF to be able to conduct meaningful analyses of stock status, the catches of the main species need to be estimated. It is considered unacceptable for member states to fail to produce data at an appropriate and consistent level of resolution.

The available data are not considered a reliable indicator of landings of elasmobranchs in the ICES area by WGEF. This is partly because many of these species are of a low value and there was never any desire on the part of national administrations to collect such data in a rigorous manner.

Since the advent of TAC’s in European fisheries there have been reasons for misreporting. Species for which quotas are restrictive are likely to have been reported as elasmobranchs such as rays and dogfish. Also, before the introduction of quotas for deepwater species, catches may have been over reported to avail of more favourable quota allocations. Therefore elasmobranch landings may be overestimated.

In 2005, WGEF spent considerable time constructing the landings data for spurdog and deepwater sharks. This process is not complete yet, but substantial progress has been made. In order to complete the task it is necessary that countries having substantial catches of generic sharks data need to participate and assist in this process.

Table 1.1. Total landings data (tonnes) for the ICES area (FAO Area 27) 1953-2002 by reporting category and reporting party. Source: FAO FISHSTAT database.

Country Total Species Total Species Total

Belgium 187,096 Angelshark 3 Portuguese dogfish 8,292 Channel Islands 4,081 Angelsharks, sand devils nei 269 Picked dogfish 1,732,692 Denmark 76,912 Angular roughshark 263 Porbeagle 65,792 Estonia 118 Basking shark 254,873 Rabbit fish 1,061 Faeroe Islands 13,298 Birdbeak dogfish 171 Raja rays nei 1,714,257 France 1,425,380 Black dogfish 576 Ratfishes nei 2,080 Germany 40,127 Blackmouth catshark 230 Sailfin roughshark 1 Greenland 215 Blue shark 6,884 Sandy ray 5,336 Iceland 33,827 Blue skate 11,010 Shagreen ray 1,837 Ireland 194,921 Bluntnose sixgill shark 8 Sharks, rays, skates, etc. nei 342,131 Isle of Man 2,913 Catsharks, nursehounds nei 192 Shortfin mako 644 Italy 2 Chimaeras, etc. nei 5 Small-eyed ray 12 Japan 2,154 Cuckoo ray 85,037 Small-spotted catshark 143,152 Korea, Republic of 42 Dogfish sharks nei 108,079 Smooth hammerhead 25 Latvia 3 Dogfishes and hounds nei 62,238 Smooth-hound 71 Lithuania 1,343 Eagle rays 148 Smooth-hounds nei 10,734 Netherlands 20,391 Greenland shark 2,822 Spotted ray 20,661 Norway 1,006,114 Gulper shark 380 Starry ray 12,807 Poland 494 Kitefin shark 585 Stingrays nei 62 Portugal 180,495 Lanternsharks nei 672 Straightnose rabbitfish 3 Romania 3 Leafscale gulper shark 2,907 Thornback ray 49,386 Russian Federation 11,691 Little sleeper shark 2 Thresher 483 Spain 519,237 Longnose velvet dogfish 15 Tiger shark 13 Sweden 17,115 Longnosed skate 4,247 Tope shark 15,413 Taiwan Province of China 104 Nursehound 5,911 Torpedo rays 346 USSR 23,395 Various sharks nei 397,851 United Kingdom 1,310,884 Uruguay 314 2,639,064

Grand Total 5,072,669

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140000 ICES Area Elasmobranch total catches 120000

100000

80000

60000 tonnes

40000

20000

0 1950 1960 1970 1980 1990 2000

Figure 1.1. Total elasmobranch landings (tonnes) by all countries, including non-member countries, in the ICES area, 1950 to present.

1.6 Discards data for elasmobranch fishes

Many countries now have regular discard sampling programmes which, although not targeted at elasmobranchs, regularly record discards of these species with the data stored in national databases. Limited discard data were presented to the working group, possibly because the data is not easily accessible in national databases. Because of the sporadic nature of discarding of elasmobranchs, it is unlikely that it would be possible to raise the data and obtain global estimates of quantities discarded as is normal. Some existing discard sampling programmes are summarised below. It is likely that other data exist that are not included here and every effort should be made to make these data available to the working group.

UK Scotland. Discards from the demersal fleet have routinely sampled since 1975 but elasmobranchs are only included in the database from 1997. Total weights discarded by the Scottish demersal fleet were estimated under the DELASS project and are presented in Section 13. It should be noted that these data are based on a small sample size and raising factors used are very large; the figures presented here should therefore be considered as indicative rather than accurate estimates.

Sampling of deep-water discards was carried out on French vessel between 1996 and 2000 and has since been continued on Scottish deep-water trawlers.

UK England and Wales. Discards are routinely sampled in the main demersal fisheries. CEFAS also has a commitment to sample discards from the anglo-spanish static gear fisheries but gaining access to vessels and, to date, only one sampling trip has been completed.

Spain (Basque Country) Some information on elasmobranch discards by several Basque Country fleets has been obtained in 2000 from two sources: from observers involved in the DELASS project, working on board of artisanal longliners targeting blue shark, andfrom observers involved in the DG Fish Project (Nº98/095) “Monitoring of discarding and retention by trawl fisheries” (Lart et al. 2002).

Spain (IEO) Data on elasmobranch discards have been obtained from two sources: a) observers involved in the DELASS project on board bottom trawl vessels, and b) observers involved in the DG Fish Project (nº PEM/93/005) “Discards of the Spanish fleet in ICES area”

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(Pérez et al. 1996). In recent years, observers have been deployed on Spanish deepwater vessels at Hatton Bank.

Ireland. Discards from the demersal fleets have been sampled since 1993. Some analysis has been carried out on these samples. There has been little sampling of the inshore <12 m fishery and only limited samples from beam-trawls. Some samples have been collected from the deep- water fleet.

1.7 Methods used.

Simulations using a length-structured population model were conducted to investigate the effects of a maximum landing size on the status of the spurdog stock. In these simulations, the population is projected forwards using a sex specific size-transition matrix obtained from a stochastic growth model with fixed von Bertalanffy growth parameters. All population dynamics processes, such as recruitment and fishing mortality are assumed to be dependent on length rather than age and are further assumed to be independent of sex. The specific biological parameters required are taken from the literature. A more complete description of the model used can be found in Dobby (2004) and Section 2.7.1 of this report.

An exploratory assessment was attempted for spurdog, based on an approach developed by Punt and Walker (1998) for school shark (Galeorhinus galeus) off southern Australia. The approach is essentially age- and sex-structured, but is based on processes that are length- based, such as maturity, pup-production, growth (in terms of weight) and gear selectivity, with a length-age relationship to define the conversion from length to age. Pup-production (recruitment) is closely linked to the numbers of mature females, but the model allows deviations from this relationship to be estimated (subject to a constraint on the amount of deviation). Apart from recruitment deviations, the model estimates virgin total biomass, and the data used in the likelihood are survey catch-rates (kg.hr-1) with corresponding CVs, and proportion-by-category data for commercial catches and surveys (categories are: pups, juveniles, sub-adults, and maturing and mature fish). All other parameters are fixed (based on external sources, such as published papers). External estimates of selectivity-at-age for both the survey and commercial catches were not available for spurdog, so the implementation includes the possibility of estimating these from proportion-by-category data from both the survey and commercial catches.

Other methods used are described in the relevant stock chapters, and were documented in previous WGEF reports and in the DELASS report (Heessen, 2003).

1.8 Ecosystem considerations

Many elasmobranchs are top-predators, and so play an important role in the ecosystem. Although most species are quite opportunistic predators, some species are more specialised.

Elasmobranch fishes typically have a slow growth rate, late age at maturity and low reproductive output, and, therefore, are generally considered to be vulnerable to over-fishing (Holden, 1974). Indeed, the populations of several species have been observed to decline in response to commercial fisheries (e.g. Holden, 1974; Rogers and Ellis, 2000) and, in more extreme cases, have also resulted in extirpation from areas within their biogeographical range (Brander, 1981). Due to the low fecundity of elasmobranchs, there is a close relationship between the stock size of mature females and recruitment.

Given that elasmobranchs are top predators and that they are vulnerable to exploitation, they may also be a useful indicator of ‘ecosystem health’.

Spawning, parturition and nursery areas are important habitats for fishes, because they play a key ecological role in maximising the survivorship and/or growth of neonatal and juvenile

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fishes. Nursery areas are often areas with high production, abundant and suitable food and habitat resources and reduced predation (Castro, 1993; Simpfendorfer and Milward, 1993). Nevertheless, the role of nursery areas in the demography and life-history of elasmobranch fishes has been little studied, and little is known about the location and importance of such areas in the ICES area.

1.9 Recommendations

Exchange format

A standard exchange format should be developed to facilitate the submission of biological, fisheries and discards, and survey data to WGEF. This could be based on existing data formats, though there is a need to have at least biological data by sex. The exact data requirements and formats will be finalised when appropriate and acceptable assessment methods are identified for the various stocks.

Dogfishes landings data

It is recommended that all nations ensure that landings data for spurdog are recorded at a species-specific level (DGS) only. Furthermore, those nations exploiting this species should undertake appropriate biological sampling. WGEF consider that there is one stock of NE Atlantic stock of spurdog.

WGEF has reconstructed landings estimates for spurdog, mainly from FISHSTAT. Much of the remaining data in the various dogfishes categories were allocated to deepwater sharks. However WGEF was unable to allocate the French data for “dogfish sharks NEI”. Thus it was impossible to evaluate what the French catch of spurdog was. Therefore WGEF recommends that France provide landings data for spurdog for 1947 to present day.

In some instances catches of miscellaneous small coastal dogfishes are landed in mixed boxes. Thus, if member states are not able to submit reliable species-specific data on the landings of small coastal sharks, dogfishes and hounds, species in this group should be reported in the category DGH only. Furthermore this category should not be used for deep-sea species. Nations with extensive fisheries for these species that to not provide accurate species-specific landings data should undertake sufficient market sampling to ensure that the species, size and sex composition of the category can be ascertained for the main metiers.

Skates and rays landings data

Nations with extensive demersal fisheries taking skates and rays, and that do not provide accurate species-specific landings data should undertake sufficient market sampling to ensure that the species, size and sex composition of the category can be ascertained for the main metiers.

Various sharks landings data

Many countries have deepwater shark landings that are either unidentified or have poor identification by species or else inadequately segregated. These member states should institute sampling schemes to segregate these catches. These countries are

• Norway • UK • Ireland • Germany

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All countries should report their deepwater sharks data to species level or provide sampling data to allow for splitting of landings. No deepwater data should be reported under DGH.

Grossly inadequate data exist on catches of the larger shark species. WGEF evaluated all FISHSTAT data from 1973 to present for “various sharks NEI” and “various dogfishes NEI” and allocated a proportion of these to deepwater sharks. The remaining data were impossible to allocate. Though a large proportion must be pelagic species. Member states reporting such data are as follows:

• Germany (Federal Republic) 1973–1989. • Spain • UK (England and Wales) • UK (Scotland) • UK (Channel Islands) • Russia • Portugal • Denmark.

These above states should make efforts to segregate these data. This can be achieved by national scientists’ examining the data by vessel or fleet to ascertain whether they are pelagic sharks or deepwater sharks. This exercise needs to be conducted by scientists from member states having experience of the fisheries.

Spanish landings statistics for “Cartilaginous fishes NEI”,“dogfish sharks NEI”, picked dogfish” and “various sharks NEI” are impossible to allocate to even generic categories. These data represent about 245 000 t of shark landings between 1973 and 2003. WGEF recommends that national scientists with experience of Spanish tuna, swordfish and demersal fisheries identify what generic or species group these substantial landings data belong to.

Porbeagle

Targeted fisheries may develop for some of these species (e.g. porbeagle) on a local scale (area and time), and it is recommended that national laboratories ensure that appropriate biological sampling (size and sex distributions) and estimates of CPUE are collected as and when such fisheries emerge.

Relations with other groups

For deep-water elasmobranchs, WGEF will continue its liaison with Working Group on the Biology and Assessment of Deep Sea Fisheries Resources. It is recommended that WGDEEP review and comment on the landings data collated in the current WGEF report, and provide WGEF with data on the landings and effort for both mixed deep-water trawl fisheries and for fisheries targeting elasmobranchs.

WGEF and other ICES Working Groups require estimates of international fishing effort for the main métiers. It is recommended that WGEF liaise with the Working Group on the Assessment of Northern Shelf Demersal Stocks (WGNSDS), Working Group on the Assessment of Southern Shelf Demersal Stocks (WGSSDS) and Working Group on the Assessment of Demersal Stocks in the North Sea and Skagerrak (WGNSSK) regarding this. It is recommended that the EU STECF determine whether such data will be available for the main métiers at an appropriate spatial scale. Such effort data are required to assist in assessing the status of spurdog, small coastal sharks, dogfishes and hounds, and skates and rays on the continental shelf, as many of these are taken in mixed otter and beam trawl fisheries.

ICES WGEF Report 2005 | 9

For ensuring that analyses of survey data are both ecologically and statistically meaningful, it is recommended that Working Group on Survey Design and Data Analysis (WGSAD) be asked to provide WGEF with details of the most appropriate methods for examining catch rates for species that are often only encountered occasionally in hauls (i.e. the majority of trawl stations have zero catches), but may have comparatively high catch rates at occasional sites.

There are several species of elasmobranch for which there insufficient data to ascertain the current status, and that many of these species occur in coastal waters, and there has been concern over their population status. It is recommended that angel shark Squatina squatina, guitarfish Rhinobatus spp., sawfish Pristis spp., electric ray Torpedo spp. and white shark Carcharodon carcharias be regarded as a “Prohibited species” that cannot be landed, at least until there are sufficient data to accurately determine their status. Comparable measures were included in the United States Fishery Management Plan (FMP) for Atlantic tuna, swordfish sharks, and highly migratory species (HMS) that inhabit the Atlantic Ocean (http://www.nmfs.noaa.gov/sfa/hms/finalFMP.html).

Considering the biological and ecological importance of elasmobranchs, and that they are of increasing conservation interest, WGEF will liase with the Working Group on Fish Ecology and the Working Group on Ecosystem Effects of Fishing Activities. It is recommended that WGFE and/or WGECO be asked to assist in determining the status of the rarer elasmobranch species in the ICES area (i.e. those species for which landings data and survey data are insufficient for more formal stock assessment).

Demographic models and ecological theory suggest that sustainable exploitation of k- strategists (e.g. elasmobranchs) may be possible given that harvesting is reduced on the mature female component of the stock. In terrestrial ecosystems, several management plans for hunting deer, goat and turkeys attempt to ensure that hunting mortality is directed to males and/or young females. Similarly, some crustacean fisheries have proposed a maximum size for females that may be landed. Affording protection to mature females, whether through differential harvesting of males or through protection measures for females (e.g. a maximum landing size, prohibition of females in catches) needs to be evaluated and it is recommended that WGEF explore and model the utility and practicability of such measures.

Measures to reduce by-catch of sharks, especially in tuna and swordfish fisheries should be evaluated by ICES. This might best be evaluated by WGFTFB. Such approaches have been taken for cetaceans.

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2 Spurdog in the North East Atlantic

WGEF considers that there is a single stock of this species in the ICES area, ranging from the Barents Sea (ICES Division I) southwards to the northern Bay of Biscay (VIIIa).

Extensive tagging studies undertaken in the North Atlantic have resulted in only isolated reports of transatlantic migrations and there is little evidence of migrations to more southerly areas. The relationship between the main NE Atlantic stock and populations in the Mediterranean and Iberian coastal waters is unclear.

2.1 The Fishery

Advice and Management Applicable to 2003 and 2004

ACFM has never provided advice for this stock.

There is a TAC for spurdog in the EC waters of the North Sea (IV) and IIa, for EC nations (Belgium, Denmark, Germany, France, The Netherlands, Sweden and the United Kingdom) and Norway. The Norwegian quota includes long line catches of other sharks (tope, velvet belly, bird beak dogfish, leafscale gulper shark, greater lantern shark, smooth lantern shark and Portuguese dogfish) that may be taken in ICES sub-areas IV, VI and VII.

The TAC for EC nations has been reduced from 8870 tonnes (1999–2001) to 7100 tonnes (2002), 5640 tonnes (2003), 4472 tonnes (2004) and 1136 tonnes (2005). The current TAC for the EC and Norway is 1236 tonnes.

Under Council Regulation 2056/2001, the EU mesh size requirement for vessels targeting spurdog is 120-219 mm.

Norway has a 70 cm minimum landing size

The fishery

Targeted spurdog fisheries operated in the Norwegian Sea, North Sea and Celtic Seas from the 1950’s to 1980’s. Peak landings were greater than 60 000 tonnes per year. Currently, spurdog are generally taken as a by-catch in trawl fisheries, typically otter trawl, and are also a by- catch or target species in gill net and long-line fisheries, which are often undertaken in seasonal inshore fisheries.

The main fishing grounds for the North-eastern Atlantic stock of spurdog are the Norwegian Sea (Sub-area II), North Sea (IV), Northwest Scotland (VI) and Celtic Seas (VII). Adjacent areas, including the Skagerrak (IIIa), Iceland (V) and northern Bay of Biscay (VIIIa) are also comparatively important, and landings of spurdog are generally low outside these areas. Spurdog is harvested primarily by the UK, France, Ireland and Norway, and the annual landings of these nations have typically been in excess of 1000 t. Smaller quantities are landed by Germany, Portugal, Belgium, Denmark, Poland, Iceland, Sweden and Spain.

Historically, spurdog was a low-value species and in the 1800’s was considered as a nuisance to pelagic herring fisheries, both as a predator and through damage to fishing nets. During the first half of the 20th century, landings of spurdog increased steadily, with annual landings of approximately 20 000 tonnes prior to the Second World War. After the war, landings increased dramatically, with annual landings in excess of 60 000 tonnes in the early 1960’s. Landings decreased during the 1970’s, though increased slightly during the 1980’s with the development of targeted gillnet and longline fisheries in the Irish Sea and western sea boards of Ireland. In recent years, reported annual landings have been less than 10 000 tonnes.

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Targeted fisheries have now declined, and in recent years most landings are from mixed trawl fisheries. Some EC nations now import spurdog taken in NW Atlantic fisheries.

Landings

In recent years, most landings of spurdog are reported under the species-specific category. However, historical data (prior to 1961) were categorized as “dogfishes etc.”. From 1961, landings were reported as either “Picked dogfish” (i.e. Squalus acanthias) or “Dogfishes and hounds”. Since 1973, the situation has been equally complicated, with several generic categories used, including “Dogfishes and hounds”, “Squalus spp”, “Squalidae” and “Squalidae and Scyliorhinidae”. All available landings data for these categories were presented by WGEF in 2003 (ICES, 2003).

WGEF has estimated annual spurdog landings using the following data:

1903–1960: Landings data from the Bulletin Statistique for the category “Dogfish etc.” have been assumed to be comprised entirely of spurdog. Landings of other dogfishes (e.g. tope and smooth hound) are assumed to be a negligible component of these catches, as these species are typically discarded in the stock area.

1961–1972: Landings data from the Bulletin Statistique for the categories “Picked dogfish” and “Dogfishes and hounds” have been used, and assumed to be comprised almost entirely of spurdog. Landings of other dogfishes (e.g. tope and smooth hound) are assumed to be a negligible component of these catches, as these species are typically discarded in the stock area. No country consistently reported both of these dogfish categories in proportions that would be consistent with the nature of the fisheries. Fisheries for deep-water sharks were not well established in the stock area in this period.

French data were lacking from the ICES database and Bulletin Statistique for the years (1966– 67 and 1969–1977 inclusive), and these data were estimated from “Statistique des Peches Maritimes”. As only aggregated shark landings were available for these years, spurdog landings were assumed to comprise 53% of the total shark landings, as spurdog comprised 50– 57% of shark landings in subsequent years.

1973-present: Landings data from the ICES database were used, and these data included species-specific data for spurdog and some of the data from the appropriate generic categories (i.e. Squalus spp, Squalidae, Dogfishes and hounds, and Squalidae and Scyliorhinidae). National species-specific data for Iceland (1980–2002), Germany (1995–2002) and Ireland (1995–2004) were used to update data from the ICES database (ICES, 2003). The following assumptions were made regarding generic categories, based on the judgement of WG members:

Belgian landings of Squalus spp. were assumed to be spurdog.

Landings of Squalidae from ICES sub-areas I-V and VII (except French landings) were assumed to be spurdog on the basis that fisheries for other squaloids (i.e. deep-water species) were not well developed in these areas over the period of reported landings. Landings of Squalidae from ICES sub-area VI were assumed to be spurdog for early periods and for nations landings low quantities. The increase in French and German landings of Squalidae in this area after 1991 and 1995 respectively were assumed to be comprised of deep-water squaloid sharks. Similarly, French landings from ICES divisions VIIb–c (all years), VIIg–k (1991 onwards) and VIII (all years) were assumed to be deep-water sharks. Landings of Squalidae from areas further south were excluded as they were out of the stock area and were likely comprised of deep-water species.

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Landings of “dogfishes and hounds” from areas VIIa and VIII were assumed to be spurdog. Landings of this category from other areas were generally low and excluded, with the assumption that spurdog contained in this category would be negligible.

Annual landings for the NE Atlantic stock are given in Table 2.1 and illustrated in Figure 2.1

2.2 Biological composition of the catch

2.2.1 Catch in numbers

Catches in terms of numbers-at-age are not available for this stock. There are some data describing the catch in numbers at length for the United Kingdom, with limited data available for other countries. These data were used in a length-based assessment (see Sections 2.6–2.7).

2.2.2 Quality of catch and biological data

Spurdog has been subject to much biological study, especially in the NE and NW Atlantic, and NE Pacific. Although routine biological sampling (e.g. age, maturity, fecundity etc.) is not currently undertaken, such parameters are available from the scientific literature. A synopsis of the biological parameters of spurdog were given in Heessen (2003) and ICES (2004a).

2.2.3 By-catch and discards information

There are no international estimates of discards by fleet and metier, and no estimates of survivorship of discarded spurdog. Preliminary investigations on discards data supplied by UK (England and Wales) for fisheries operating in western areas and in North Sea were undertaken (Figure 2.2). These data are limited, and have been aggregated across all gears and divisions in the North Sea and western waters. These data highlight that the majority of spurdog are retained in the various fisheries. Few juveniles were observed in these discards trips, but it is likely that fish <45 cm total length would generally be discarded, as such sized fish are generally not apparent in market sampling.

2.3 Fishery-independent information

2.3.1 Groundfish surveys

Fishery-independent survey data are available for most regions within the stock area, although the tendency for shorter trawl durations in some areas (i.e. tows of 30 minutes as opposed to one hour) may affect the interpretation of survey trends. Those surveys operating in the stock area include the internationally-coordinated IBTS surveys in the North Sea and Skagerrak, and southern and western areas.

This species is very much under-represented in beam-trawl surveys, and although they are sampled by GOV trawls and other otter trawls, analyses of catch data need to be undertaken with care. Spurdog is a relatively large-bodied species (up to 120 cm in the NE Atlantic), and adults are strong swimmers that forage both in pelagic and demersal waters. Furthermore, spurdog is an aggregating species that shoals by size and sex, and large catches can be made periodically. Hence, survey data generally include a large number of zero catches, and occasional catches comprising large numbers of specimens, thus causing a high variance in survey data.

The size distribution of spurdog in the North Sea (Figure 2.3) indicates that spurdog of 65–85 cm total length are the predominant part of catches in Q3 surveys, with proportionately more pups and juvenile spurdog (20–55 cm) caught in Q1 surveys.

The size distribution of spurdog off North-west Scotland (Figure 2.4) indicates that pups and juveniles (20–55 cm) are the predominant part of catches, with mature females comparatively

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infrequent. These size classes are also an important component of Celtic Sea catches, as are mature and maturing males (70–80 cm). Catches in the Irish Sea tended to have the greatest proportion of large fish (>85 cm), and the majority of fishes at these lengths are female.

Given the large variance in catch rates, identifying accurate trends in CPUE are problematic. What is apparent, however, is that spurdog occur in proportionately fewer hauls in the Celtic Sea in recent years (Figure 2.5). More striking is that the proportion of hauls in which large catches of spurdog (e.g. with a CPUE _ 20 ind.h-1) occur has declined since the 1980’s (Figure 2.6).Although haul duration in the period 1982–1984 were 60–120 minutes, tow duration has been standardised at 60 minutes since 1985. Hence, the decline in large catches is not an artefact of tow duration. In summary, though the survey data are variable, there is a trend of decreasing occurrence, decreasing frequency of large catches, and the average numbers of fish in moderate catches (where CPUE is 1–19ind.h-1) has declined (Figure 2.7).

Examination of the Scottish west coast first quarter survey provided comparable results. Spurdog now occurs in proportionately fewer hauls in recent years (Figure 2.8), and once again the proportion of hauls in which large catches of spurdog (CPUE ≥ 20 ind.h-1) occurred has declined since the 1980’s (Figure 2.9). Although haul duration in the period 1985-1998 was 60 minutes, tow duration was reduced to 30 minutes since 1999. The main decline in the proportion of survey hauls with large catches occurred before 1999, and so is not an artefact of tow duration. The overall trends in this survey also indicate a trend of decreasing occurrence and decreasing frequency of large catches. The average numbers of fish in moderate catches (i.e. mean CPUE at stations where catch rates were 1–19 ind.h-1) has remained more stable in this survey (Figure 2.10).

2.4 Mean length, weight, maturity and natural mortality-at-age

Although there have been several studies in the North Atlantic and elsewhere describing the age and growth of spurdog, there is no routine monitoring of length, weight and maturity at age for either survey or commercial catches.

Natural mortality is not known, though estimates ranging from 0.1-0.3 have been described in the scientific literature (Aasen, 1964; Holden, 1968). WGEF has assumed that M=0.1, though will likely to be higher for the first age groups.

2.5 Recruitment

Pups (16–31 cm length) are occasionally taken in groundfish surveys, and such data may be able to assist in the preliminary identification of pupping and nursery areas. Given the low catch rates and high variability of pups and juveniles in surveys, these data are insufficient to estimate annual recruitment.

2.6 Stock assessment

2.6.1 Previous studies

Earlier meetings of SGEF and WGEF have attempted to undertake assessments of NE Atlantic spurdog. The methods employed during the 2002 SGEF meeting (ICES, 2002a) and DELASS project (Heessen, 2003) included catch curve analysis and separable VPA using length distributions sliced according to growth parameters from the scientific literature, and a Bayesian assessment using a stock production model, with a prior for the intrinsic rate of increase set by demographic methods.

The former method indicated that the mature population had declined (Figure 2.11), though the conclusions that could be drawn from this study were highly dependent on the growth

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parameters used for slicing. Further studies are needed to examine the sensitivity to growth model parameter uncertainty.

The Bayesian assessment estimated that spurdog were very likely to be at less than 10% of carrying capacity, and possibly as low as 5% of virgin biomass (ICES, 2002a, Figure 2.12; Hammond and Ellis, 2005), though this assessment had several assumptions. Firstly, growth parameters were based on published values, though there is some uncertainty in the ageing of spurdog, especially for larger fish. This assessment also discarded some survey observations (zero catches), the model assumed the stock was at carrying capacity in 1946 and that the parameters r and K have remained constant since 1946, and the model ascribed no uncertainty to the landings data.

Following on from preliminary length-based models developed during the 2002 SGEF meeting, continued studies were undertaken (ICES, 2003) using a length-based approach using a modified catch-at-size analysis (CASA) (see Sullivan et al., 1990). Estimates of spawning stock biomass and total biomass for both males and females from this model showed a sharp decline, with female spawning biomass appearing lower than male (Figure 2.13).

2.6.2 Data exploration and preliminary modelling

An exploratory assessment was attempted for spurdog, based on an approach developed by Punt and Walker (1998) for school shark (Galeorhinus galeus) off southern Australia. The approach is essentially age- and sex-structured, but is based on processes that are length- based, such as maturity, pup-production, growth (in terms of weight) and gear selectivity, with a length-age relationship to define the conversion from length to age. Pup-production (recruitment) is closely linked to the numbers of mature females, but the model allows deviations from this relationship to be estimated (subject to a constraint on the amount of deviation). Other parameters estimated by Punt and Walker (1998) included the magnitude of density dependence in pup-production and the virgin total biomass, and the data used in the likelihood are commercial catch-rates by gear. All other parameters (including those that define selectivity) are fixed (based on external sources, such as published papers).

The implementation for spurdog was coded in ADModel Builder (Otter Research) within a relatively short space of time, and analyses should be considered exploratory until it has undergone appropriate checks, sensitivity analyses and further development. The approach is similar to Punt and Walker (1998), but ignores density-dependence in pup-production and fits to a survey index of abundance (initial studies used the Scottish West Coast Q1 survey), which was calculated as the average catch rate (kg.hr-1) of positive stations, multiplied by the proportion of positive stations. CVs were calculated in a similar manner, and were very high. External estimates of selectivity-at-age for both the survey and commercial catches were not available for spurdog, so the implementation includes the possibility of estimating these from proportion-by-category data from both the survey and commercial catches (aggregated across gears). Four categories were considered for the survey proportion-by-category data, namely length-groups 16–31 cm (pups); 32–54 cm (juveniles); 55–69 cm (sub-adult); and 70+ cm (maturing and mature fish). The corresponding age-categories were: 0; 1–5; 6–8 (females) or 6–9 (males); and 9+ (females) or 10+ (males). The first two categories were combined for the commercial catch data to avoid zero values.

The only estimable parameters considered where total virgin biomass and recruitment deviations (survey catchability was estimated using a closed-form solution). The model in its current form was not able to estimate selectivity parameters, possibly because of the parameterisation of the selectivity curves (a gamma function is used), and these need to be reconsidered, or alternatively specified outside the context of the model (as in Punt and Walker, 1998). The model also assumes a single commercial catch exploitation pattern that

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has remained constant since 1947, which is an oversimplification given the number of gears taking spurdog, and the change in the relative contribution of these gears in directed and mixed fisheries over time. Growth is considered invariant, as in the Punt and Walker (1998) approach, but growth variation could be included (Punt et al., 2001). The survey index considered for the spurdog implementation may not be appropriate, given the patchy nature of survey data and the shoaling behaviour of the species – a further evaluation of this data is currently underway.

Preliminary results confirmed that spurdog have declined, and that the decline is driven by high exploitation levels in the past, coupled with biological characteristics that make this species particularly vulnerable to such intense exploitation.

This model may be appropriate for improving assessments of spurdog, though the model could be better developed if the following data were available:

• Selectivity parameters disaggregated by gear for the main fisheries (i.e. for various trawl, long line and gillnets) • Appropriate indices of relative abundance from fishery-independent surveys, with corresponding estimates of variance • Improved estimates for biological data (e.g. growth parameters and reproductive biology).

Another possible assessment method for spurdog is the approach of Kristensen et al. (2005), who use a size-spectra model that assigns individual growth patterns to each recruit, assumes size-selective mortality, and estimates spectra-model parameters based only on scientific trawl survey length data. The approach uses length-based CPUE from individual hauls as raw data, instead of the mean CPUE, so that the stochastic variation between individual hauls is determined from analysis of data. The use of such an approach is relevant when age determination is uncertain and the quality of catch data poor.

2.6.3 Stock assessment

No new assessment was undertaken, as methods are still being developed.

2.7 Simulation of effects of maximum landing size regulations

Earlier demographic studies on elasmobranchs indicate that low fishing mortality on mature females is beneficial to population growth rates (Cortés, 1999; Simpfendorfer, 1999). Hence, measures that afford protection to mature females may be an important element of a management plan for the species. As with many elasmobranchs, female spurdog attain a larger size than males, and larger females are more fecund. The sex ratio of spurdog by length from commercial and research vessel catches are illustrated in Figure 2.14.

2.7.1 Methods

The length-structured population model which was used in the catch-at-size analysis (CASA) described in Section 2.6.1 can also be used as a simulation tool with fixed input parameters. tool with fixed input parameters. It can therefore be used to investigate the effects of altering exploitation pattern and rate on stock status.

The model uses a size-transition matrix approach to project the population length distribution forwards in time. The sex specific size-transition matrix is obtained from a stochastic growth model with fixed von Bertalanffy growth parameters. All population dynamics processes, such as recruitment and fishing mortality, are assumed to be dependent on length rather than age. It is further assumed that these processes are independent of sex so that equal numbers of males and females recruit to the fishery, and fishing mortality at length is identical. A fuller description of

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the population model can be found in Dobby (2004). A number of specific assumptions are made for the spurdog model which are discussed below.

Model assumptions

Growth

The mean growth for individuals of a particular length is described by a von Bertalanffy

growth function with sex specific parameters. The values used were L∞= 111 cm, K = 0.086 -1 -1 yr for females, and L∞= 81 cm, K = 0.17 yr for males. These are the mean of the values reported by Sosinski (1977), Fahy (1989), Holden and Meadows (1962) and Henderson et al. (2001). Variability in growth is modelled using a beta function.

Natural mortality

A natural mortality of 0.1 yr-1 (Aasen, 1964) is assumed in this model. It is further assumed to be independent of length and sex.

Fishing mortality

Fishing mortality is assumed to be separable into a temporal component and a fixed length dependent exploitation pattern so that

Fly = f y sl

where fy is an annual fishing mortality multiplier and sl is the length dependent exploitation pattern.

Maturity

The proportion mature at length was assumed to follow a logistic ogive with 50% maturity at 80 cm for females and 64 cm for males. Values of female length at 50% maturity from the literature include 74cm (Fahy, 1989), 81cm (Jones and Ugland, 2001) and 83cm (Gauld, 1979).

Recruitment

Total annual recruitment to the population is calculated from a function based on the length distribution of mature females as fecundity has been shown to be related to size (Gauld, 1979).

f Ry = ∑0.5*(a + bl)p f ,l Nl,y ll >70cm f Where Nl,y is the number of females with length l in year y, pf,l is the proportion of females mature at length l (parameters given above) and a=-23.876 and b=0.344 are parameters estimated from Gauld (1979). The factor of 0.5 is included in the relationship to account for the protracted spawning period of 22 months. Total annual recruitment is assumed to be divided equally between males and females.

Recruitment is assumed to occur over a range off lengths, the distribution is assumed to be Gaussian with mean length = 26 cm (Gauld 1979) and standard deviation of 2 cm.

Simulations

Some simple simulations are conducted here in which both the exploitation pattern and exploitation rate are assumed fixed. The simulations are run for 60 years from 1970 onwards. The length dependent exploitation pattern is assumed to be represented by a logistic curve with s50 (length at 50% exploitation) = 60 cm and k (slope of curve) = 0.2.

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1 s = l (1+ e −k (l−s50) )

The length at 50% exploitation used in these simulations is rather lower than the values estimated in the previously presented catch-at-size analysis. These analyses were based only on length frequencies from England and Wales, which seem to consist of a rather high proportion of large individuals. Initial comparisons with limited length frequency data obtained from Scottish fisheries show a higher number of smaller females in the catch and therefore the fishing mortality of smaller individuals is likely to be higher than previously estimated. From 2006 onwards, a maximum landings size is implemented with the assumption that discard survival of individuals above this length is 100% (i.e. fishing mortality of zero).

2.7.2 Results

The results of simulations with maximum landings sizes of 70 cm, 85 cm and 90 cm are shown in Figure 2.15. Implementing a maximum landing size of 70 cm in 2006 results in a very sudden drop in catch, but the stock biomass and recruitment are predicted to increase very quickly and this results in increasing catches after a few years, although it is approximately 15 years before catches return to their current levels. Only a small proportion of the current catch is above 85 cm and therefore protecting individuals above either 85 or 90 cm has only a small immediate effect on the level of the catch. Consequently the increases in stock biomass and recruitment are slower in these cases.

As the assumed fishing mortalities used in these simulations have not been obtained from an analytic assessment of the stock, the results should be viewed as illustrative of what may happen when such management strategies are implemented. In particular, levels of biomass, catch, etc should certainly not be regarded as absolute. Such simulations should be explored further with alternative assumptions about discard survival, incorporating stochasticity into recruitment values and with different exploitation strategies.

2.8 Reference points

No reference points have been proposed for this stock.

2.9 Quality of the assessment

The assessments provided above are preliminary, as the nature and quality of the data are highly variable.

2.10 Pupping and juvenile fishing area closures

There is limited information on the distribution of spurdog pups, though they have been reported to occur in Scottish waters, in the Celtic Sea and off Ireland. The lack of accurate data on the location of pupping and nursery grounds, and their importance to the stock precludes spatial management for this species at the present time.

2.11 Management considerations Spurdog were subject to targeted fisheries, though are now most often taken as a by-catch in mixed fisheries, and most targeted fisheries have ceased. Analyses of fishery-independent survey data highlight that spurdog are less frequently caught in groundfish surveys, and that the number of hauls with large catches of spurdog has also decreased. WGEF consider that the NE Atlantic stock of spurdog is depleted and that urgent measures are required to prevent stock collapse. Measures that should be established should include a maximum landing size, and target fisheries should not be allowed to proceed. Additional

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measures may also be required in order to allow the stock to better rebuild. Data are either limited or too variable to determine accurately by how much the stock is depleted.

Spurdog are considered to be highly vulnerable to over-exploitation, as they have a low population productivity, low fecundity and protracted gestation period. Furthermore, targeted long line and gillnet fisheries have exploited aggregations of large fish (i.e. mature females).

Those fixed gear fisheries that capture spurdog should be reviewed to examine the catch composition, and those taking a high proportion of mature females should be subject to technical measures.

Measures to afford protection to mature females (e.g. through a maximum landing size) may have benefits to the stock, depending on the survivorship of discards in the various fisheries. Survey data indicate that at a length of 85 cm, 75% of spurdog are female, and at 90 cm more than 95% of spurdog are female (Figure 2.14). Given that spurdog aggregate by sex and size, a maximum landing size may also serve to deter fisheries targeting mature females.

While there is no EU minimum landing size for spurdog, there is some discarding of smaller fish, and it is likely that spurdog of <40 or 45 cm are discarded in most fisheries. The survivorship of discards of juvenile spurdog is not known.

The TAC for spurdog in the EC waters of the North Sea (IV) and IIa, for EC nations and Norway between 1999–2004 has not restricted the fishery (Figure 2.16).

The TAC area should correspond to the stock’s distribution, which covers ICES sub-areas I– VIIIa. In 2004, Germany proposed that the EU propose that spurdog be listed under Appendix II of CITES (i.e. so that nations involved in the import/export trade would have to show that the harvesting and utilisation was sustainable). Sweden has recently added spurdog to their national Red List.

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70000

60000

50000

40000

30000

20000

10000

0 1905 1910 1915 1920 1925 1930 1935 1940 1945 1950 1955 1960 1965 1970 1975 1980 1985 1990 1995 2000

Figure 2.1: Landings of NE Atlantic spurdog (1905–2004)

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Spurdog

60 50 40 30

Number 20 10 0 30 40 50 60 70 80 90 100 110 120 Total length (cm)

Discarded Retained

Figure 2.2a: Length distribution of Squalus acanthias discarded and retained in fisheries in western waters. These data are aggregated across individual catch samples for all gears and divisions combined (Source: UK (E&W) Discards surveys).

Spurdog

10 Number 5

0 30 40 50 60 70 80 90 100 110 120 Total length (cm)

Discarded Retained

Figure 2-2b: Length distribution of Squalus acanthias discarded and retained in fisheries in the North Sea. These data are aggregated across individual catch samples for all gears and divisions combined (Source: UK (E and W) Discards surveys).

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(a) North Sea (Q1, FRS)

35 30 25 20 15 10 5 0 15 25 35 45 55 65 75 85 95 105 115

Female Male

(b) North Sea (Q3, FRS)

70 60 50 40 30 20 10 0 15 25 35 45 55 65 75 85 95 105 115

Female Male

600

500

400

300

200

100

0 15 25 35 45 55 65 75 85 95 105 115

Female Male

Figure 2.3: Size distributions of male and female spurdog in the North Sea from (a) Scottish quarter 1 surveys (1985–2005), (b) Scottish quarter 3 surveys (1985–2004) and (c) English surveys (1977–2003).

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(a) West Coast (Q1, FRS)

1600 1400 1200 1000 800 600 400 200 0 15 25 35 45 55 65 75 85 95 105 115

Female Male

(b) West Coast (Q4, FRS)

800 700 600 500 400 300 200 100 0 15 25 35 45 55 65 75 85 95 105 115

Female Male

500

400

300

200

100

0 16 26 36 46 56 66 76 86 96 106 116

Female Male

(d) Irish Sea (DARD)

80 70 60 50 40 30 20 10 0 15 25 35 45 55 65 75 85 95 105 115

Combined

Figure 2.4: Size distributions of male and female spurdog in the Celtic Seas region from (a) Scottish west coast quarter 1 surveys (1985–2005), (b) Scottish quarter 4 surveys (1985–2004), (c) English surveys in the Celtic Sea (1977–2003) and (d) DARD surveys in the Irish Sea (1991–2001).

ICES WGEF Report 2005 | 23

Occurrence in traw l catches (%)

80 70 60 50 40 30 20 10 0 1982(q1) 1983(q4) 1984(q4) 1985(q4) 1986(q4) 1987(q4) 1988(q4) 1990(q1) 1992(q1) 1994(q1) 1996(q1) 1998(q1) 2000(q1) 2002(q1)

Figure 2.5: Frequency of occurrence of Squalus acanthias in survey hauls in the Celtic Sea (1982- 2002)

Proportion of stations with catches >20 (%)

25.0

20.0

15.0

10.0

5.0

0.0 1982(q1) 1983(q4) 1984(q4) 1985(q4) 1986(q4) 1987(q4) 1988(q4) 1990(q1) 1992(q1) 1994(q1) 1996(q1) 1998(q1) 2000(q1) 2002(q1)

Figure 2.6: Proportion of survey hauls in the Celtic Sea (1982–2002) in which occurrence of Squalus acanthias was ≥ 20 ind.h-1.

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Spurdog in the Celtic Sea

45.0

1987

1990

30.0 1989 1988

1992 1991 1999 1996 1995 1993 15.0 2000 2001 1994 1997 1998 Frequency of occurrence (%) occurrence Frequency of 2002

0.0 01234567 Mean CPUE (where CPUE is >0 and <20)

Figure 2.7: Abundance-occupancy relationship of spurdog in the Celtic Sea (1987–2002). Bubble size is proportionate to the frequency of large catches.

Occurrence in trawl catches (%)

0 1985 1986 1987 1988 1989 1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005

Figure 2.8: Frequency of occurrence of Squalus acanthias in survey hauls in the Scottish west coast survey (Q1, 1985–2005).

ICES WGEF Report 2005 | 25

Proportion of stations with catches >20 (%)

0 1985 1986 1987 1988 1989 1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005

Figure 2.9: Proportion of survey hauls in the Scottish west coast survey (1985–2005) in which CPUE of Squalus acanthias was ≥ 20 ind.h-1.

West coast Q1 survey

100.0

80.0 1985

1986 60.0 1990 1987 1994

1991 1993 1992 1989 40.0 1988 1995 1996 1998

Frequency of occurrence (%) ofoccurrence Frequency 1999 1997 2000 2001 2002 20.0 2005 2003 2004

0.0 2468 Mean CPUE (where CPUE >0 and <20)

Figure 2.10: Abundance-occupancy relationship of spurdog from the Scottish west coast survey (1985-2005). Bubble size is proportionate to the frequency of large catches. 26 | ICES WGEF Report 2005

2500000

0.05 2000000

0.1 1500000 0.2 0.3 1000000

500000

0 1980 1985 1990 1995 2000 2005

Figure 2.11: The trends in total population numbers of mature fish estimated using a Separable VPA analysis of the catch numbers at age data derived from length slicing of the UK(E and W) commercial spurdog landings raised to the total recorded landings for all countries. Each line represents a different assumption for terminal F (0.05 – 0.3) on the reference age in the final year (From Figure 4.1.13 of ICES (2002a)).

Biomass time series

800000 700000 600000

500000 Lower 5% 400000 Median 300000 Upper 5% 200000 100000 0 1977 1981 1985 1989 1993 1997 2001 Year

Figure 2.12: The biomass time series estimated from a Bayesian assessment (From Figure 4.1.20 of ICES (2002a)).

ICES WGEF Report 2005 | 27

exploitation pattern recruitment 50

millions 20

0 10 50 90 130 1985 1990 1995 2000

length (cm) Year Ft catch 50 1.5 data 40 model 1.0 30 '000 t 20 0.5

0.0 0 1985 1990 1995 2000 1985 1990 1995 2000

Year Year Female biomass Male biomass 100 100

total total 80 80 SSB SSB

60 60 '000 t '000 t 40 40

20 20

0 0 1985 1990 1995 2000 1985 1990 1995 2000

Year Year

Figure 2.13: Summary of model results from a length-based assessment of NE Atlantic spurdog (From Figure 4.1.8 of ICES (2003)).

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100

50 % Females 25

0 33 42 51 60 69 78 87 96 105 <25 Total length (cm)

Survey data Commercial catch

Figure 2.14: Sex ratio of spurdog at length, as estimated from fishery-independent survey data and from commercially landed fish.

ICES WGEF Report 2005 | 29

Exploitation pattern Catch

70 cm 1.2 8 1 85 cm 6 0.8 90 cm 0.6 4

0.4 '000 t 2 0.2 0 0 0 20 40 60 80 100 120 140 1970 1980 1990 2000 2010 2020 2030 cm Year

Recruitment Total biomass

12 100 10 80 8 60 6

'000 t 40

millions 4 2 20 0 0 1970 1980 1990 2000 2010 2020 2030 1970 1980 1990 2000 2010 2020 2030 Year Year

Female spawning biomass Male spawning biomass

25 20 20 15 15 10 '000 t

10 '000 t 5 5

0 0 1970 1980 1990 2000 2010 2020 2030 1970 1980 1990 2000 2010 2020 2030 Year Year

Figure 2-15. Summary of length-based simulations with alternative maximum landing sizes.

18000

16000

14000

12000

10000

8000

6000

4000

2000

0 1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005

Figure 2.16. Estimated landings of spurdog from areas IIa, III and IV (line) with TAC (grey bars) as allocated to Norway and EC nations. ICES WGEF Report 2005 | 30

Table 2.1: Total landings of NE Atlantic spurdog (1947–2004).

Landings Landings Landings Year Year Year (Tonnes) (Tonnes) (Tonnes)

1947 16893 1967 44116 1987 44898

1948 19491 1968 56043 1988 37730 1949 23010 1969 52074 1989 30204 1950 24750 1970 47557 1990 29874 1951 35301 1971 45653 1991 29447 1952 40550 1972 50416 1992 28819 1953 38206 1973 49412 1993 23159 1954 40570 1974 45684 1994 21034 1955 43127 1975 44119 1995 20245 1956 46951 1976 44064 1996 16707 1957 45570 1977 42252 1997 14957 1958 50394 1978 47235 1998 14088 1959 47394 1979 38201 1999 11197 1960 53997 1980 40943 2000 15514* 1961 57721 1981 39961 2001 16007* 1962 57256 1982 32402 2002 9138 1963 62288 1983 39386 2003 8808 1964 60146 1984 39449 2004 5079 1965 49336 1985 41126 1966 42713 1986 35098 * May include some mis-reported deep-sea sharks or other species

3 Deep-water sharks in the North East Atlantic (ICES Areas I–XIV)

A number of species of deepwater sharks are exploited in the ICES area. This section deals mainly Centrophorus squamosus and Centrocymnus coelolepsis, which are of greatest importance to commercial fisheries in the northern area. Off Portugal, small scale fisheriesoperate for several other species and these are dealt with in Section 4.

LEAFSCALE GULPER SHARK (Centrophorus squamosus) has a wide distribution; in the eastern Atlantic from Iceland and Atlantic slope (off Ireland, Scotland and Portugal) to the Canary Islands, Senegal, Faeroes, Madeira, Azores, Gabon to Dem. Rep. Congo, Namibia, and western Cape of Good Hope (South Africa). On the Mid-Atlantic Ridge it is distributed from Iceland to Azores (Hareide and Garnes, 2000) The species can live as a demersal shark on the continental slopes (depths between 230 and 2400 m) or present a more pelagic behaviour, occurring in the upper 1250 m of oceanic water in areas with depths around 4000 m (Compagno and Niem, 1998). Data on stock identity is inconclusive, though available evidence suggests that this species is highly migratory. In the absence of more clear information on stock identity, a single assessment unit of the Northeast Atlantic has been adopted.

PORTUGUESE DOGFISH (Centrophorus coelolepis) is widely distributed in the Northeast Atlantic. Stock structure and its dynamics are poorly understood. Specimens below 70 cm have been very rarely recorded in the NE Atlantic. There is a lack of knowledge on migrations, though it is known that females move to shallower waters for parturition and vertical migration seems to occur (Clarke et al. 2001). In the absence of more clear ICES WGEF Report 2005 | 31

information on stock identity, a single assessment unit of the Northeast Atlantic has been adopted.

These two species are usually referred to as “siki sharks”

3.1 The fishery

3.1.1 Advice and management applicable to 2005 and 2006

Only in 2002, did ACFM provide management advice for deepwater sharks. In 2002 ACFM reported that the state of deep-water sharks was unknown. Mixed species CPUE were declining, which is consistent with decreasing abundance of the complex of deepwater shark species as a whole, and particularly with a deteriorating state of species preferred or most vulnerable when the deepwater fisheries for sharks expanded/commenced.

Based on that, 2002 ACFM advice on management was: Deepwater sharks can sustain only very low exploitation rates. They are taken in mixed fisheries, which make it difficult to manage them in a single-species context. Due to the declining trends in CPUE, despite the mixed nature of the catches, ICES recommended that the overall exploitation be reduced. ICES further advised that species-specific landings data be collected for all deepwater sharks to allow better understanding and quantification of the status of exploited shark species. ACFM also considered that other relevant factors needed to be considered in management, namely, without information on trajectories of individual species’ abundances, it is not possible to advise on the size of the reduction in exploitation necessary for the fisheries to be sustainable, but it is more likely to be large (e.g. 50%) than small (e.g. 10%). Moreover, due to the biology of these species, such reductions would have to be maintained for several years before the status of the more heavily exploited stocks will show evidence of recovery. In 2004, ACFM reviewed the status of these stocks and concluded that there was no evidence that the situation had changed.

Annual fishing opportunities in zones in Community waters and in certain non Community waters for stocks of deep-sea species were fixed for 2005 and 2006 (EC no 2270/2004 article 1). Fishing opportunities for stocks of deep-sea shark species for Community vessels were presented in an Annex (EC no 2270/2004 article 3) (Table 3.1). A list of species was given to be considered in the group of ‘deep sea sharks’.

The TAC for V, VI, VII, VIII and IX is 6763 t. In Sub-area X the TAC is 14 t. In Sub-area XII for these and other species is 243 t. This is allocated by country. These quotas apply to the following list of species: Portuguese dogfish (Centroscymnus coelolepis), Leafscale gulper shark (Centrophorus squamosus), Birdbeak dogfish (Deania calceus), Kitefin shark (Dalatias licha), Greater lanternshark (Etmopterus princeps), Velvet belly (Etmopterus spinax), Black dogfish (Centroscyllium fabricii), Gulper shark (Centrophorus granulosus), Blackmouth dogfish (Galeus melastomus), Mouse catshark (Galeus murinus), Iceland catshark (Apristuris spp.). In Subarea XII, Deania histicosa and Deania profundorum are added to this list.

3.1.2 The fishery

C. squamosus and C. coelolepis are both taken in several mixed trawl fisheries in the northeast Atlantic and in mixed and directed longline fisheries.

The deepwater fisheries (trawl and longline), taking these sharks in this area have been extensively described, see ICES (1998; 2004). However the gillnet fisheries, targeting deepwater sharks are only recently receiving attention, though some notes on these fisheries were made in ICES (1998). These fisheries were described as part of an international project entitled DEEPNET (Hareide et al., 2004) that aimed to get basic information about deep-water set net fisheries in NE Atlantic.

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The gillnet fishery was initiated at the mid-1990s on the continental slopes to the West of the British Isles, North of Shetland, at Rockall and the Hatton Bank in depths between 200 and 1200 meters. Monkfish (Lophiidae) and deepwater sharks (C. coelolepis and Centrophorus spp.) are the main target species of this fishery. The fleet is composed of vessels, mostly based in Spain but registered in the UK, Germany and other countries outside the EU such as Panama. This fishery was largely unregulated, with little or no information on catch composition, discards and a high degree of suspected misreporting.

UK vessels are now monitored through an observer scheme, and it is expected that reliable data on fishing practises, catches, and discards will be available for the 2006 WGEF.

Country by country accounts are presented as follows:

Norway – Norwegian longliners target blue ling (Molva dypterigia), Mora (Mora moro) and leafscale gulper shark (Centrophorus squamosus) on the continental slope between 800 and 1100 metres. In 2000 and 2001, a longline fishery for Greenland Halibut with a bycatch of Portuguese dogfish operated on Hatton Bank between 1300 and 1600 metres. The fishery in 2004 was carried out by only one vessel fishing in area VI and XII. This vessel targeted blue ling, mora, and deep water sharks in depths between 700 and 1200 m.

Faroes - A directed longline fishery on deep water sharks was carried out in the southern and western slopes of Faeroes Island from 1995 to 1999. No detailed information on this fishery is available although anecdotal information suggests that fishing was developed at depths between 800 and 1200 meters in the slopes west of the Wyville Thompson Ridge and south of the Faeroe Bank Plateau.

Germany - Two German vessels have been conducting a deep-water gillnet fishery in recent years (Hareide et al., 2004). The main fishing area is Southern part of area VII (Porcupine Seabight and around Rockall. (Area VI and XII) The deepwater sharks are landed in Spain as various sharks.

France – C. squamosus and C. coelolepis and lately, Centroscyllium fabricii, are landed by the French trawl fishery for mixed deep-water species. Initially this fishery was conducted in ICES sub-areas VIa, VIIc,k but in 2001 when the Irish deep-water trawl fishery started to operate in Subarea VII most of the French fishing fleet moved to Subarea VIa.

In Sub-area XII there have been some French landings of deep-water sharks, but it is not possible to detect any trends from the available data. Note that this Sub-area contains both the western part of Hatton Bank and the Mid-Atlantic Ridge.

Ireland – An Irish longline fishery targeting ling and tusk in the upper slope and deep-water sharks started in 2000 and ceased in 2003. Mainly two species of deep water sharks are marketed, C. coelolepis and C. squamosus. There have been some landings of birdbeak dogfish and longnose velvet dogfish.

Several large new trawlers have targeted deepwater species in Sub-areas VI and VII. There is a directed fishery for orange roughy in Subarea VII, with a low a by-catch which includes C. coelolepis and C. squamosus as well as a more extensive fishery on the continental slopes of Sub-areas VI and VII for mixed deep-water species including C. coelolepis and C. squamosus.

UK – Since 1991, UK registered longliners and gillnetters have operate a directed fishery for deep water sharks in subareas VI, VII and XII. In 2003–2004 the gillnet fishery was conducted by 11 vessels with the main fishing grounds located at western part of Porcupine (Division VII) and around Rockall

ICES WGEF Report 2005 | 33

C. squamosus and C. coelolepis are landed by a Scottish deep water mixed-species trawl fishery operating mainly in Sub-area VI. Since the introduction of TAC´s for a number of deep-water species in 2003, effort has declined considerably.

Spain - A fleet of around 24 large freezer trawlers conducts a mixed deepwater fishery in international waters of the Hatton Bank, mainly in ICES Subarea XII and partially in Division VIb, however, few of these vessels worked full time in this fishery (two in 2000 and four in 2001). The main commercial fish species are smoothheads, roundnose grenadier, blue ling and Portuguese dogfish. In addition, some of the trawlers were operating occasionally in international waters at Reikjanes Ridge (ICES Division XIVb), during few days of the spring targeted to blue ling.

An overview of the updated Basque deep-sea fishery has been presented to the WD by Lucio et al. (2004). The Basque “baka” trawl fishery operates in subareas VI and VII and divisions VIIa,b,d, but deep-water species including sharks are important only in only in subarea VI. In the period 1997–2002, a small long line fishery landed annually in Basque ports about 150 t in “trunk” weight (i.e. gutted and without head, skin and fins) of deep-water sharks.

Portugal – At Sesimbra (Division IXa), the longline fishery targeting black scabbardfish Aphanopus carbo takes a bycatch of deep-water sharks, The most important shark species caught by this fishery are the Portuguese dogfish and leafscale gulper sharks. Deep-water sharks are also caught by the Portuguese deep-water bottom trawl fishery that targets the rose shrimp Parapenaeus longirostris and Nephrops mainly south and southwest of the Portuguese mainland. Deep-water shark species caught in this fishery are: birdbeak dogfish, blackmouth catshark, gulper shark, kitefin shark, leafscale gulper shark, smooth lanternshark Etmopterus pusillus and velvet belly.

A directed longline fishery for deep-water sharks, based at Viana do Castelo in northern Portugal, was initiated in 1983 and the landings in this fishery predominantly consisted of gulper shark. leafscale gulper shark and Portuguese dogfish are caught in relatively smaller quantities. In more recent years only one longliner has fished full time. There is also another longliner with a continuous activity along the year that is registered at Sesimbra landing port. This longliner targets deep-water sharks, mainly C. coelolepis but C. squamosus is also caught.

Landings from the directed fishery for deep-water sharks in the Azores, in which the kitefin shark Dalatias licha has been targeted by both gillnets and handlines, peaked at 950 t in 1981 and have decreased to 40 t in 1998 (Table 5.3). The last boat operated until 1998, after which the fishery ceased. Presently, a few small open-deck boats have returned to the traditional handlines to fish for kitefin shark, with landings of about 30 t in 1999 and 2000. Deep-water sharks are also caught as bycatch both from the general demersal and black scabbardfish fisheries, but the landing data are not collected by species.

3.2 Biological composition of the catch

3.2.1 Quality of catch and biological data

In 2005, WGEF reconstructed the catch data for deep-water sharks. The data are still incomplete and inadequately segregated and further errors may arise from the application of incorrect conversion factors, however, the best estimates of catch currently available were produced and the method used to derive these estimates is documented below.

Since the start of the fishery, a number of generic categories have been used to report landings of deep water sharks - these include “various sharks not elsewhere identified (NEI)”, “dogfish sharks NEI” and “cartilaginous fishes NEI”. This has made it very difficult to quantify landings of deep-water sharks, particularly as the same categories are often used to report

34 | ICES WGEF Report 2005

other species such as pelagic sharks or spurdog. In many cases, knowledge of the fisheries operating in a particular area at the time makes it possible to determine the most likely identity of these landings. In some cases it is not possible to be certain that the sharks were deep-water species but this division represents the best judgement of the group. The shark landings which the working group considers likely to be deepwater sharks have been included in the working group estimates for siki sharks (Figure 3.1.). This category consists mainly of C. squamosus and C. coelolepis but probably also contains a small component of other species.

In more recent years, an increasing quantity of sharks has been reported in species specific categories however examination of the data suggests that a certain amount of misidentification has taken place. Where the group is satisfied that reported landings are reliably identified, they have been included in species specific tables, while all others have been included in the siki estimates. Some countries such as Portugal have supplied species specific data for many years.

Examination of the “cartilaginous fishes NEI data” suggested that none of it referred to siki. The two categories most likely to contain deep-water species are “various sharks NEI” and “dogfish sharks NEI”. All the data in these categories in the FISHSTAT database were examined and, where possible, those considered likely to be deep-water species allocated as follows

The following records of various sharks NEI in the FISHSTAT database were considered to be deepwater species and have been included in the working group estimates for siki sharks.

• UK-Scotland; all subareas from 1989 to 2001 (data supplied by to the working group by Scotland were used for more recent years) • UK-England and Wales; subareas V, VI and VIIc, from 1990 to 2002 (data supplied to the working group by CEFAS were used for more recent years. • Portugal; Subarea VIIIc 1990 to 2000 • Poland; Subarea VIb 2002 and 2003 • Estonia; VIb in 2002 and 2003 • Lithuania; landings in subarea XII between 2001 and 2003.

The remainder of the records in this category were considered more likely to be other species with the following exceptions;

• France; although French landings were thought likely to be siki, more reliable data were supplied to WGDEEP 2002, and these have been used. • UK-England and Wales: Landings in Subareas VIId–k and VIII – probably include both siki and pelagic sharks. Further examination of the national database will be necessary to determine the identity of these landings. • Portugal: Landings in Subareas VIII and IX – probably include both siki and pelagic sharks. Further examination of the national database will be necessary to determine the identity of these landings.

The following records of dogfish sharks NEI in the FISHSTAT database were considered to be deepwater species and have been included in the working group estimates for siki sharks.

• German landings in subareas V, VI, VII and XII between 1995 and 2003

All other data entered in this category was considered more likely to be other species such as spurdog

Some landings data in the FISHSTAT is identified to species level however, it is not always certain that this is reliable. For example, it is probable that some records of Portuguese dogfish include both siki species.

ICES WGEF Report 2005 | 35

• Faroes: records of Portuguese dogfish probably contain unknown quantities of leafscale gulper shark and have been included in the siki sharks estimates • France: all data in FISHSTAT was replaced by data provided to WGDEEP 2002 • Iceland: records of Portuguese dogfish considered to be correct. • Ireland: records of Portuguese dogfish probably contain unknown quantities of leafscale gulper shark and have been included in the siki sharks estimates • Lithuania: records of Portuguese dogfish probably contain unknown quantities of leafscale gulper shark and have been included in the siki sharks estimates • Norway: records of Portuguese dogfish considered to be correct • Portugal: data from FISHSTAT were replaced by data supplied by Portugal • UK E&W: records of Portuguese dogfish and leafscale gulper shark probably contain a mixture of species and have been included in the siki sharks estimates. Data from 2003 and 2004 replaced with data from CEFAS • UK Scotland records: of Portuguese dogfish probably contain unknown quantities of leafscale gulper shark and have been included in the siki sharks table. Records of Leafscale gulper shark are considered to be correct.

Data supplied to the group

• UK-England and Wales supplied landings from the Anglo-Spanish longline and Gillnet fleet which were broken down by species. The group considered that species identification by the fishermen was likely to be unreliable and so the data has been combined as unidentified deep water sharks and included in the siki estimates (Tables 3.2 and 3.3). • UK – Scotland. Data were separated by species but it was considered likely that identification as unreliable and so data were included in siki shark estimates (Table 3.4) • Data supplied by Norway were not separated by species and have been included in the siki shark estimates. • Data supplied by the Basque Country were not separated by species and have been included in the siki shark estimates.

The working group was satisfied that catch estimates derived through this analysis are now very close to the total landings for the deep-water sharks. One outstanding exception is in the catches from UK England and Wales before 2003 from subarea VIIe–k which probably includes a mixture of deep-water and pelagic species. These have been excluded from the catch estimates meaning that the total landings are probably still underestimated. It will be necessary to examine the data in the UK database more thoroughly, possibly even going back to the level of identifying individual vessels, in order to solve this problem. An additional and major problem is related to the increasing quantities of liver and oil, which are most certainly a mixture from different species, and thus cannot easily converted to species live weight. Before 1996, the catches may be underestimated due to the retention of oil only, and discarding of carcasses.

3.2.2 Length and age frequencies

Length frequencies were only provided by Portugal. Several other countries may have length frequency data for these species and these will be available to future working groups. A common format for exchanging this information will be developed for the next WGEF meeting.

Portuguese longliners – Length frequency distribution based on samples collected under the IPIMAR landing sampling program for males and females of C. squamosus in 2002 and 2003 are presented in Figure 3.2.

36 | ICES WGEF Report 2005

Length frequency distribution based on samples collected under the IPIMAR landing sampling program for males and females C. coelolepis in 1999 and 2000 are presented in Figure 3.3.

3.3 Fishery-independent information

Independent fishery data are scarce and spatially restricted for these species. Survey data were available from Norway (autoline) and Ireland (autoline and trawl) for several years from 1991 to 2000 and 2005 trawl Irish survey (Table 3.5).

Survey CPUE were included in the analysis, only for the middle of the known range of the bathymetric distributions of C. coelolepis (1100–1600 m) (Clarke et al., 2001). These data were not directly comparable with the commercial data because the latter are for the two species combined, so survey CPUE was pooled for both species, including those catches where their bathymetric ranges overlap (see also Section 6.4.6).

Since 1996, Scotland has conducted deep-water surveys in division VIa and, since 2000, these have been conducted as regular biennial surveys on the continental slope between 55 and 59 degrees north. Surveys prior to 2000 cannot be regarded as forming part of a continuous data series with later surveys, as there was a change of vessel in 1998 and of gear in 2000. Surveys since 2000 used the same gear and vessel but did not always exactly replicate fishing positions and the 2004 survey was truncated due to a breakdown. Numbers of hauls per survey and catch rates of deep-water sharks are presented in Tables 3.6 to 3.8.

3.4 Catch per unit of effort

Neither Portuguese dogfish nor leafscale gulper shark form dense aggregations and may be considered to be evenly distributed through its optimal depth range (ICES, 2002). In contrast with species displaying a more aggregating behaviour, bycatch CPUE is therefore considered to be an adequate estimator of stock abundance in these species and it was considered appropriate to use the non-target commercial CPUE series for the investigation of possible assessment approaches (ICES, 2002).

There are some CPUE series available for different European countries using both commercial and survey data, however, not all of them are discriminated by species. WGEF spent much time compiling the available data.

The different time series available, as well as the procedure used to discriminate some of them to species level is described below.

France - A CPUE series from a reference fleet of French trawlers for Portuguese dogfish and leaf-scale gulper shark, collectively called “siki”, was presented to WGDEEP (ICES, 2002, Table 17.3). This series was calculated from total landings from these vessels and total effort directed at all deep-water species combined. A different CPUE series was presented at SGDEEP (ICES, 2000, Table 17.2), based on the same fleet of French trawlers, but calculated from catches by vessels whose effort was considered to be directed at squalids, i.e., if it produced more than 10% of total catch or 20% of total annual catch, by statistical rectangle (Lorrance and Dupouy, 2001). The WGDEEP 2002 series produced lower estimates of CPUE. The two CPUE series for Subarea VI, where most effort takes place, displayed downward trends until 1998. The WGDEEP 2002 series did not display the high peak in the SGDEEP 2000 series for 1991, though the value for 2001 was the highest since 1994.

In 2004, French trawl CPUE series were presented for several deep-water teleost species caught in the same fishery (WGDEEP report ICES; 2004b). In this CPUE series, it became evident that clear change in fishing pattern occurred in sub-area VI from 1999 onwards. During this period, it is evident that black scabbardfish became a more important species,

ICES WGEF Report 2005 | 37

becoming in recent years the target of the French trawl fishery. As a result of this, the fishing grounds explored by the French trawlers are now deeper and as a consequence, more deep- water sharks are caught together with black scabbardfish (a species which presents a high correlation level with deep-water sharks in this fishery). In view of this, the French CPUE data from area VI from the years 1999 and 2000 should be excluded from the analysis since they do not represent the same fishing pattern as shown in earlier years from either CPUE series. In addition, and since that subarea VI covers huge variety of habitats (such as Rockall Trough, the western and Northern slopes of Rockall and Hatton bank) a change in the fishing grounds might have a strong influence on the CPUE estimate.

French CPUE data were presented as mixed siki. To split these CPUE by species, several sources of information were available, namely, landing data from French landings ports (Concarneau, Lorient and Boulogne) from 1994 to 1998 (ECFAIR, 1999) and French landings at Scottish landing port from 1999 to 2001 (Crozier, 2003). From 2002 to 2004 an increasing fraction of the French landings are reported by species. All these sources were used to get estimates of French trawler CPUE by species (Table 3.9; Figures 3.4 and 3.5).

Across the period for which species composition is available, C. coelelopis has become increasingly important in the landings; it increased from a level of 50 % in 1995 to nearly 80% in 2003. Although the reason for this change it is not known yet, it might be due to changes in fishing pattern. French trawlers have increasingly explored deeper grounds as a result of increased targeting black scabbardfish, as mentioned before. This seem to be further supported by the markedly increase in siki sharks CPUE in subarea VI in 1999 and 2000.

Ireland – There are CPUE information from both Irish trawlers and longliners from subarea VII, however, these are for combined siki catches and are not differentiated by species.

To get trawler CPUE for each of two main species included in the “siki” category (Table 3.9) three different sources of data on species composition were used: i ) onboard observer data for 2001, 2003 and 2004 ii ) survey data for 2005 iii ) personal Logbooks for 2002 and 2003. The personal logbooks only contained landings of Portuguese dogfish since leafscale gulper shark was at that time discarded by the Irish trawlers.

Personal logbooks from Irish longliners were available for 2001 and 2003. Also official logbooks were available from 2001 to 2003 (Table 3.10). Both these two series only gave landings for combined “siki” species. These two CPUE series were further split into species using Irish longliner survey data composition in sub-area VII in 1999; and from observer data in 2001 and in addition sampling data for species composition in 2003. It is important to notice that during the overall time period, a change in relative occurrence of the two species has occurred; C. coelolepis in 1999 represented 24% of landings but in 2003 was reduced to 12%. This might reflect a decrease on the population of pregnant female population which tends to concentrate in depths around 800 m, which have been heavily exploited by many European deep-water fisheries.

Portugal – Preliminary Portuguese longliner CPUE was given for C. coelolepis and C. squamosus. The data were derived from personal logbook but are still considered preliminary because, although globally covering several years, there were gaps with no information in some months which were not necessarily the same in the different years. Since the source of CPUE data from the Portuguese continental slope comprises only two vessels and the period analysed was very short (4 recent years only), a more comprehensive evaluation of the effects of the exploitation should only be conducted when data are available for a longer time period. Other sources of information such as VMS data from fishing vessels catching deep-water sharks were not yet analysed. As a consequence the Portuguese longliner CPUE estimates

38 | ICES WGEF Report 2005

should be analysed with caution avoiding any extrapolation which might not mirror the real situation in IX ICES subarea.

The levels of uncertainty in CPUE estimates were not the same over the years for the two species; while in first three years the CV were around 50%, in the last the two years were about the 30%.

Norway – The Norwegian longline CPUE series for sub-area XII were available from surveys in 1996, 1999 and 2000 and from onboard observer program for 2001 (Table 3.9). These series were given by species.

TRENDS in CPUE

Subarea V – in this Subarea, there is only CPUE information from the French trawlers (Tables 3.11 and 3.12; Figures 3.6. and 3.7). Despite the uncertainties on the CPUE estimates, it seems evident that in both species there is a clear decreasing trend in CPUE for both species.

• C. squamosus has been reduced in 2001 to around 20% of the level recorded in 1995. • C.coelolepis has been reduced in 2001 to around 50% of the level recorded in 1995.

Although there is no information available on changes in fishing pattern in this Subarea, the general tendency of French trawlers towards deeper fishing grounds might also be reflected in the CPUE trends.

Subarea VI – in this subarea several CPUE series are available for French trawlers and also for Irish and Scottish surveys (Tables 3.11 and 3.12; Figures 3.6 and 3.7). The Irish survey was only performed in one year, so it is not used for comparison purposes. The information from French trawlers shows that:

• C. squamosus has been reduced in 2001 to around 34% of the level recorded in 1995. • C.coelolepis, there is no clear trend.

In case of the Scottish trawl surveys CPUE is expressed as numbers of individuals per hour. The information is available for the years 2000, 2002 and 2004 and shows:

• C. squamosus has been reduced in 2004 to around 20% of the level recorded in 2000. • C. coelolepis. has been reduced in 2004 to around 20% of the levels recorded both in 2000 and 2002.

Subarea VII – in this Subarea, several CPUE series are available from Irish trawlers and longliners, French trawlers and Irish longliners surveys (Tables 3.11 and 3.12; Figures 3.6. and 3.7). The information from trawlers shows that;

• C. squamosus has reduced in 1999 to around 23% of the level recorded in 1995 for French trawlers. For Irish trawlers the reduction in 2004 was around 14% of the levels recorded in 2001. The CPUE from Irish commercial longliners shows a reduction from 2001 to 2003. The Irish longliner surveys, which took place in 1997 and 1999, show no changes in CPUE between those two years. • C.coelolepis: there is no clear downward trend in the French trawlers CPUE, however, in the Irish trawlers there is a very strong decline from 2001 to 2004 and 2005. In these last two years, the levels of CPUE were about 10% that recorded in 2001. In the Irish longline survey, which took place in 1997 and 1999, the level in 1999 was about 67% of that registered in 1997. In the Irish longliner fishery the CPUE from 2003 for area VIIbc was about 41% of the 2001 level, whereas for division VIIk, it was almost the same with a CPUE of 91% of

ICES WGEF Report 2005 | 39

the one registered in 2001. The fishery moved from VIIbc because of the unprofitable CPUE. On some small peaks in division VIIk it was possible to continue the fishery for a year but by the end of 2003 it was also considered unprofitable in this area.

Subarea IX – in this Subarea, a CPUE series is available from personal log book from Portuguese longliners (Tables 3.11 and 3.12; Figures 3.6. and 3.7). These estimates are very preliminary and only cover the most recent years

• C. squamosus CPUE in 2004 was around 74% of the level recorded in 2001. • C.coelolepis CPUE in 2004 was around 92% of the level recorded in 2001.

Subarea XII – in this Subarea, CPUE series from French trawlers, Norwegian longliner surveys and Norwegian commercial longliners (Tables 3.11 and 3.12; Figures 3.6 and 3.7) show that;

• C. squamosus has been reduced in 1999 to around 32% of the level recorded in 1995 in French trawlers. The CPUE from Norwegian commercial longliners in 2001 was about 1% of that registered in 1999. The Nowegian longliner surveys, which took place in 1998 and 1999, show also a high decrease of CPUE; the level registered in 1999 was about 2% of that in 1998. • C.coelolepis has been reduced in 2001 to around 80% of the level recorded in 1995 in French trawlers. The CPUE from Norwegian commercial longliners in 2001 was about 16% of that registered in 1999. The Nowegian longliner surveys, which took place in 1998 and 1999, show no clear decline on the CPUE between those two years.

3.4.1 Discards

Ireland - Irish trawl fishery operating in Division VII discarded C. squamosus in 2002–2003, however by the end of 2004 the species began to be landed. All the landings from this fishery reported, as “Siki” are in fact Portuguese dogfish. Based on interviews and on the official landings registered to this fishery it was possible to estimate landings on a species level. Observer program onboard vessels from this fishery took place from 2001 to February 2005, which allowed estimating the species composition of discards and discard rates. The landings of deepwater sharks have been used as raising factor for discards of C. squamosus.

In the Irish longline fishery, 2000–2003 there was no discards of C. squamosus.

France - Discards in the French trawl fisheries were described in the FAIR report (ECFAIR, 1999) and by Blasdale and Newton (1998). Levels of discarding were found to be very low for both of these species.

Norway - Norwegian longliners land both C. coelolepis and C. squamosus. However these two species are commonly discarded in fishery for ling and tusk in the upper slopes of Hebrides, Porcupine bank and Rockall (400–700 m) (ICES Subareas VIa, VIb and VII) they are normally discarded, however there is no sampling program to estimate discard levels.

A program of cooperation between sales organizations and the Norwegian Directorate of Fisheries, gave some information on discards from Greenland halibut fishery. Logbooks were collected from three longliners and a trawler participating in the feasibility study. By weight, the discards represented 47% and 43% of the total catch in ICES sub-areas Ia and IIa respectively. Sampling was carried out during the first two weeks of the feasibility fishery and hence before dense concentrations of Greenland halibut were found. The catch compositions therefore did not reflect the real situation in the commercial fishery and cannot be used to calculate total discards in the fishery (STECF, 2003).

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Some Norwegian vessels fishing on the deep slope (800–1100 m) and targeting blue ling and mora discard both C. squamosus and C. coelolepis while others land both species under the generic name of Siki. The levels of discarding from these vessels can however be estimated based on catch compositions from surveys in the same areas and time period.

Portugal - In the early years of the Portuguese longline fishery to the North of Portugal (Viana do Castelo) targeting deep-water sharks and particularly, gulper shark, only livers where retained on board. Because of this, high levels of discards (eviscerated specimens) were expected to occur during that period (years 1992 to 1997). Since that period, the whole bodies of deep-water sharks have been landed.

British and German gillnetters target deep-water sharks or monkfish west of the UK and Ireland. Although there are no discard data for deep-water shark, the discards rates of monk from this fishery were tentatively estimated to be around 60–70%. (Hareide et al., 2004). The main reason for this high level of discarding is long soak times (4–10 days) and consequent high rates of degradation of the specimens. In view of these observations, there are good reasons to believe that there is also a high proportion of discards of deep-water sharks.

There are no data currently available on discards in the shark gillnet fishery on the lower slope, although if long soak times are practised discards may also be high. UK vessels participating in this fishery are now monitored through an observer scheme, and it is expected that further data and direct observations on fishing practises, catches, and discards will be available for the 2006 WGEF.

3.5 Mean length, weight, maturity, natural mortality and recruitment

For most of the European fisheries independently of the fishing gear used, mature (pregnant) females of C. coelolepis are commonly caught, while in C. squamosus pregnant females are rarely caught by the commercial vessels. This difference might cause greater impact on the vulnerability of C. coelolepis to exploitation.

3.5.1 Leaf scale gulper shark

C. squamosus attains a maximum length of 1.6 m (Compagno and Niem, 1998). Early work suggested that the species attains maturity at ~100 cm TL in males and at ~125 cm in females (Girard and Du Buit, 1999; Clarke et al., 2001). However this value can be underestimated since it was based on females with mature oocytes in the ovary and recent information suggests that this stage has a long duration (Figueiredo et al., 2005, WD).

C. squamosus is an aplacental yolk sac viviparous species. With the exception of two specimens caught in Portuguese waters, pregnant females have not been caught in the Atlantic and a single pup found on Madeira fish market is the only known observation of this life stage. Early studies indicated no apparent seasonal reproductive cycle in males (Girard, 2000). Recent studies with specimens from Portuguese slopes suggest that the species has a discontinuous breeding cycle with a gestation period of between 22 and 24 months. Large females may loose their reproductive capacity. One female carrying 6 full-term embryos (without vestiges of yolk sac) was caught in August, perhaps suggesting that extrusion occurs during summer months. The mean length of embryos was around 46 cm, which is thus assumed to correspond to length at birth (Figueiredo et al., 2005, WD). In New Zealand and Australia females with 5-8 young born at a length between 35 and 43 cm have been recorded. (Last and Stevens, 1994; Cox and Francis, 1997). There is some preliminary data on the dietary compositions of this species (Ebert et al., 1992).

ICES WGEF Report 2005 | 41

3.5.2 Portuguese dogfish

In most Atlantic fisheries there is a dominance of females in landings, which may indicate sexual segregation with depth. Additionally, females with mature oocytes are more abundant at the same depth as active mature males (Girard and Du Buit, 1999; Clarke et al., 2001; Verissimo et al, 2003).

3.6 Stock assessment

3.6.1 Previous assessments of stock status

The first preliminary assessment on C. coelolepis (combined with C. squamosus) was attempted by SGDEEP (ICES, 2000) using the available series of catch and effort from French reference fleet trawlers as inputs. The series of CPUE data presented in WGDEEP (ICES 2002b Table 17.2) formed the basis of attempted assessments. In all cases, however, these assessments were considered to be too unreliable to be included in the report of that working group.

Further analyses of stock status were presented in Basson et al. (2002) describes the results from the SGDEEP assessments of deep-water sharks using Schaefer and Delury analyses and from presence/absence analyses of long-term RV time-series data. This study showed that it is evident that the relative importance of larger size females increased in recent years. In addition the percentages of non-zero hauls in Scottish research trawl surveys shows a decline in percentage of hauls with C. coelolepis declined between 1975 and 2000.

A second attempt was made during DELASS. The French CPUE data for Sub-areas V, VI and VII for C. coelolepis and C.squamosus together were used as inputs. The combined CPUE for these Sub-areas was calculated from the total catch and effort data presented in WGDEEP report (ICES, 2002b). These data did not display as marked an upward trend as shown in the WGDEEP report (ICES, 2002b). Both CPUE data sets were used as inputs. The time series for Subarea VI, where most effort takes place, both displayed downward trends until 1998. The WGDEEP 2002 series did not display the high peak in the SGDEEP 2000 series for 1991. However, the value for 2001 is the highest since 1994. There is no similar upward trend for the other sub-areas, and it is unclear what the reasons for this trend are. The series for the Sub- areas combined displayed the same trend, indicating the importance of effort in Subarea VI on these sharks. However, there is no anecdotal evidence from the fishery to suggest that there is an upward trend in abundance in 2000 or 2001.In addition, Norway (autoline) and Ireland (autoline and trawl) survey abundance indices in Subarea VI did not mirror the upward trend in CPUE from the French commercial fishery. Furthermore, the pooled species data, from autoline surveys displayed a downward trend from 1997 to 2000. In Subareas VII and XII there is some evidence of a decline in survey CPUE throughout the 1990’s.

In the second attempt the CPUE data for siki representing non-directed effort as input to Schaeffer Production Model, using the CEDA package (Holden et al,. 1995). This model and package were chosen to allow for comparisons to be made with the previous assessment attempted for these stocks. A sensitivity analysis was used to evaluate the effect of error models and ratio of initial to virgin biomass. A time-lag of zero was used because that the time series of catch and CPUE were too short to explore the effect of recruitment over range of years. It was assumed, therefore, that growth rather than recruitment was the main contributor to biomass production. The available time-series data of CPUE data show a gradual decline across most of the time period. Given this sort of pattern, caution is needed because of the “one-way trip” (Hilborn and Walters, 1992) resulting in highly unreliable estimates of the parameters of this model. A value of the ratio of initial stock to virgin stock was chosen as 0.7, based on sensitivity analysis. The fit of the Schaeffer production model was very poor when all years were included. It was considered reasonable to exclude years 1991–1993 because the

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fishery was not fully developed then. The directed CPUE series (ICES, 2000) displayed a peak in 1991. However non-directed CPUE did not display a first peak until 1993, which probably reflected the targeting of the orange roughy fishery in Sub-area VI at that time. The years 2000 and 2001 were excluded because there was no supporting evidence of an upward trend in stock abundance in these years. Subsequent runs of the Schaeffer model gave a better model fit than when all years were included. Two additional scenarios were considered, using the WGDEEP 2002 CPUE and the CPUE recalculated in DELASS from the raw catch and effort data. The model was considered to fit the downward trend on abundance quite well, for the years considered.

Many of the output parameters from the Schaeffer production model are poorly estimated (Intrinsic rate of population increase (r) and maximum sustainable yield) and should not be used to assess the developments in these stocks. Carrying capacity and catchability seemed to be estimated with narrower confidence intervals. It was stressed that since the estimates of carrying capacity are sensitive to the catch data used, the absence of species-specific data is a cause for concern. Given that Portuguese dogfish has a deeper bathymetric distribution than the leafscale gulper shark, the combined series may mask important trends in their respective abundance. Further refinement of species-specific catch and effort data, perhaps considering other reference fleets should be carried out. Such work would be particularly valuable in the case of the fisheries that have taken place for the longest duration (French trawl and Portuguese longline fisheries). The stock of Portuguese dogfish certainly has not stabilised during the 1990’s. Estimates of maximum sustainable yield (MSY) and intrinsic population growth rate (r) derived from stock production models cannot be usefully applied with the current model fits.

3.7 Reference points

No reference points have been proposed for this stock.

3.8 Quality of the assessment

Reliable catch and effort data at a species-specific level are important requisites for the improvement of assessment outputs.

3.9 Management considerations

There is clear evidence of a decline in abundance of both species. Stocks are clearly depleted, though it is not possible to know what level the stocks are currently at. There is a need to restrict effort.

The current TAC and WG estimates of landings are presented in Figure 3.8. It is clear that the quota is restrictive for some countries, if adequately enforced. For other countries, the quotas are not effective to regulate fishing effort.

It is unacceptable that species specific data are still not presented for these two species. The WGEF considers that fisheries should not proceed if adequate data are not collected to assess the sustainable exploitation levels. Such data include, especially species-specific catch data.

There is information that illegal unregulated and unreported fishing of these species is taking place by non-ICES countries in the ICES area.

The situation of the fishing impact on deep-water sharks, namely the two siki species, is not uniform across different ICES Subareas. In Subareas VI and VII the average landings are quite high in the period 1996 to 2003, of an order of magnitude of about 6500 tonnes in recent years, while in other areas such as subarea IX, catches are relatively stable over the entire period (1000). Also, while in subareas VI, VII and XII deep-water sharks are caught by

ICES WGEF Report 2005 | 43

several fishing gears (trawl, longliners and gillnets), in Subarea IX deep-water sharks can only be caught by longliners due to the Portuguese legislation of licensing deep-water vessels.

The fact that in subareas VI, VII and XII several different fishing fleets using different fishing gears are catching deep-water sharks means that that, together, they are acting across the major optimal depth of deep-water sharks occurrence. This situation seems to have a major impact in C. coelolepis since the depth range of commercial exploitation includes both depths of around 800 m where pregnant females tends to concentrate and greater depths, were the remaining of populations occurs. The predominance of mature females in the catch, a large proportion of which is pregnant, together with the increasing trends in the catches of this species ( the ratio of C. coelolepis versus C.squamosus have increased in the last years) which implicitly seems to reflect an increasing depth of fishing operations, is a cause of special concern. A high fishing pressure on females and increasing pressure on deeper grounds may impair the reproductive capacity and severely impact the stock structure.

In Subarea IXa CPUE data are only available since 2000, so it is difficult to detect trends. The ratio of the two species has been unchanged in this area.

It is clear that depletion of both these stocks has occurred in the ICES area. The current level of these fisheries is unsustainable. WGEF considers that directed fisheries for these species should cease.

The gillnet fishery can be better evaluated in 2006 on the basis of detailed data on catches, fishing effort, soak times and discards, collected in 2005 under the UK observer scheme. It should also be noted that the largest proportion of the catch of deep-water sharks from these areas is taken in mixed trawl fisheries, and fishing effort in these fisheries should likewise be severely reduced and/or subject to appropriate spatial restrictions.

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Table 3.1 - TACs and quotas for deep-water sharks

Zone: V, VI, VII, VIII, IX (Community waters and international Species: Deep Sea Sharks waters)

Germany 161 Spain 767 Estonia 10 France 275 Ireland 448 Lithuania 10 Poland 10 Portugal 1044 UK 1538 EC 6763

Species: Deep Sea Sharks Zone: X (Community waters and international waters)

Portugal 14 EC 14

Deepsea sharks and Deania Zone: XII (Community waters and international histicosa and Deania waters) profondorum Spain 169 France 54 Ireland 10 UK 10 EC 243

ICES WGEF Report 2005 | 45

Table 3.2 - UK landings into England and Wales in 2003 and 2004. (tonnes) (Official data from CEFAS UK).

2003 2004 Leafscale gulper shark 1313 1345 Portoguese dogfish 1080 1109 Gulper shark 580 460 Total 2973 2914

Table 3.3. - UK (England and Wales) landings outside the UK 2003 and 2004. (tonnes) (Official data from CEFAS UK).

2003 2004 TOTAL Kitefinshark 421 200 621 Leafscale gulper shark 1135 1170 2305 Portuguese dogfish 976 961 1937 Gulper shark 380 346 726 Red Crab 668 205 873 Blue ling 6 3 9 Black scabbardfish Longnose velvet dogfish 334 175 509 Bird beak dogfish 19 46 65 Unidentified dogfish 7 1 8 Unidentified sharks 18 29 47 Greater Forkbeard 64 54 118 Greenland Halibut 3 2 5 Ling 505 416 921 Liveroil 342 685 1027 Spiny Scorpion fish 2 2 Velvet belly 10 10 Total 4878 4305 9183 Total siki sharks 2111 2131 4242 Leafscale gulper shark % 53,8 54,9 54,3 Portuguese dogfish% 46,2 45,1 45,7 Table 3.4 - Landings by species of gillneteres landing into Scotland. Data from official logbooks. (Marine Lab, Aberdeen)

1997 1998 1999 2000 2001 2002 2003 2004 Deepwater Crabs 0,0 0,0 1,0 4,4 3,4 69,6 312,3 113,284 Leafscale gulper 0,0 0,0 0,0 0,0 0,0 0,0 108,6 62,878 (False siki) Kitefin 0,0 0,0 0,0 0,0 0,0 0,0 29,2 0 Spurdog 235,0 217,9 260,9 311,7 142,2 18,9 35,8 9,608 Gulper shark 0,0 0,0 0,0 0,0 0,0 0,0 52,1 18,855 Monkfish (Gutted) 623,7 884,3 855,3 660,7 984,8 624,2 721,9 1043,442 Portuguese shark (Siki) 21,0 34,4 0,1 0,0 408,7 421,5 276,2 202,302

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Table 3.5 – CPUE (kg/1000 autoline hooks; kg/hour trawled) data for C. squamosus and C. coelolepis from Norwegian and Irish research surveys in the Northeast Atlantic. Gear configurations were the same for both countries (Heesen, 2003)

C. squamosus C. coelolepis Combined Sub Area Country Date Gear 600– 1000 1100– 1600 600–1600 VI Ireland 1997 Autoline 218 70 133 VI Norway 1999 Autoline 219 83 178 VI Norway 2000 Autoline 42 92 86 VI Ireland 2000 Autoline 24 76 38

VII Norway 1996 Autoline 221 227 264 VII Ireland 1997 Autoline 56 158 69 VII Ireland 1999 Autoline 51 107 61 VII Ireland 2000 Autoline 73 166 81

XII Norway 1999 Autoline 100 128 174 XII Norway 2000 Autoline 78 98 113 XII Ireland 2000 Autoline 38 19 33

XIV (b) Norway 1991 Autoline 8 8

VI Ireland 1993a Trawl 55 62 VI Ireland 1993b Trawl 63 8 49 VI Ireland 1995 Trawl 15 11 14 VI Ireland 1996 Trawl 48 9 37 VI Ireland 1997 Trawl 24 25 20 VI Scotland 1996 Trawl 1.1 1.1 VI Scotland 1997 Trawl 28.0 28.0 VI Scotland 1998 Trawl 27.7 27.7 VI Scotland 2000 Trawl 22.6 22.6 VI Scotland 2002 Trawl 22.1 22.1 VI Scotland 2004 Trawl 5.0 5.0

VII Ireland 1993a Trawl 6 32 VII Ireland 1995 Trawl 242 197 VII Ireland 1996 Trawl 30 26 27 VII Ireland 1997 Trawl 6 15 15 VII Ireland 2005 Trawl 1 2 Table 3.6 -Numbers of valid hauls by depth category in Scottish deep-water surveys

Year Depth category 1996 1997 1998 2000 2002 2004 Total 0-499 2 6 5 4 17 500-999 13 29 17 13 11 11 94 1000-1499 1 10 9 5 25 1500-1999 5 7 6 18 Total 13 29 20 34 32 26 154 ICES WGEF Report 2005 | 47

Table 3.7 -CPUE (numbers/hour) of Portuguese dogfish by depth in Scottish surveys area VIa.

Year Depth category 1996 1997 1998 2000 2002 2004 0 0.00 0.00 0.00 0.00 500 6.09 15.53 24.39 7.02 2.00 0.50 1000 0.67 25.02 9.00 1.07 1500 19.60 22.86 12.00 Mean 6.09 15.53 8.35 17.21 11.29 4.52 Table 3.8 - CPUE (numbers/hour) of leafscale gulper shark by depth in Scottish surveys area VIa.

Year Depth class 1996 1997 1998 2000 2002 2004 0-499 0.00 0.00 0.00 0.00 500-999 1.11 27.96 27.67 22.56 22.11 5.00 1000-1499 0.00 10.52 16.00 3.00 1500-1999 2.00 1.00 1.00 Mean 1.11 27.96 9.22 8.77 9.78 2.25

Table 3.9 – Ratios of C. squamosus and C. coelolepis used for splitting CPUE series from different fleets and gear.

C. C. Landing port Area Fleet Year coelolepis squamosus Reference or Depth range % % NE Atlantic Fr. trawlers 1994 59 41 Concarneau & Lorient (ECFair,1999) NE Atlantic Fr. trawlers 1994 61 39 Concarneau & Lorient (ECFair,1999) NE Atlantic Fr. trawlers 1995 48 52 Concarneau & Lorient (ECFair,1999) NE Atlantic Fr. trawlers 1995 47 53 Concarneau & Lorient (ECFair,1999) NE Atlantic Fr. trawlers 1996 54 46 Concarneau & Bologne (ECFair,1999) NE Atlantic Fr. trawlers 1997 58 42 Concarneau & Bologne (ECFair,1999) NE Atlantic Fr. trawlers 1998 61 40 Concarneau & Bologne (ECFair,1999) NE Atlantic Fr. trawlers 1999 75 25 Lockinver (Crozier, 2003) NE Atlantic Fr. trawlers 2000 67 32 Lockinver (Crozier, 2003) NE Atlantic Fr. trawlers 2001 71 29 Lockinver (Crozier, 2003) NE Atlantic Fr. trawlers 2002 83 17 All ports IFREMER NE Atlantic Fr. trawlers 2003 88 12 All ports IFREMER NE Atlantic Fr. trawlers 2004* 56 44 All ports IFREMER VI &VI Irish longliners 1997 29 71 700–1200 m Survey VII Irish longliners 1999 24 76 700–1200 m Survey VII Irish longliners 2000 25 75 700–1200 m Privat logbook XII(Hatton) Irish longliners 2001 93 7 1100–1500 survey Vib Irish longliners 2001 19 81 700–1200 m Privat logbook VII Irish longliners 2001 700–1200 m Survey VII Irish longliners 2003 12 88 700–1200 m Landings NE Atlantic English and German gillnetters 2003 45 55 Official Logbook NE Atlantic English and German gillnetters 2004 45 55 Official Logbook XII(Hatton) Norw. longliners 1999 9 91 600–1100 m Survey XII(Hatton) Norw. longliners 2000 57 43 1000–1500 m Survey XII(Hatton) Norw. longliners 2001 Observers

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Table 3.10 – Relative proportion of C. coelolepis and C. squamosus in Irish longline fishery (1997– 2003)

Year C. coelolepis C.squamosus Division Depth Source 1997 29 71 VI &VI 700–1200 Survey m 1999 24 76 VII 700–1200 Survey m 2000 25 75 VII 700–1200 Privat logbook m 2001 93 7 XII(Hatton) 1100–1500 survey 2001 19 81 Vib 700–1200 Privat logbook m 2001 30 70 VII 700–1200 Survey m 2003 12 88 VII 700–1200 Landings m

Table 3.11 - C. squamosus CPUE series from different fleets and gear.

French French French French Irish Scottish Irish Irish Norw Norw Portuguese Trawlers Trawlers Trawlers Trawlers trawlers Trawl Longline Longline longline comm. longline area V area VII area VI area XII VII surveys surveys fishery surveys Longline fishery area VII VII IX * VI XII XII Kg/h Kg/h Kg/h Kg/h Kg/h n/h Kg/h Kg/1000 Kg/1000 Kg/1000 Kg/1000 hooks hooks hooks hooks 1990 1991 1992 1993 1994 37 28 40 40 1995 51 30 53 53 1996 58 21 41 41 1997 24 22 33 33 56 1998 23 17 35 35 1999 9 7 18 18 51 219 138 2000 11 20 20 9 42 14 97 2001 8 16 16 35 182 2 94 2002 10 192 82 2003 144 58 2004 5 2 65 2005 2

* preliminary estimates

ICES WGEF Report 2005 | 49

Table3.12 - C.coelolepis CPUE series from different fleets and gear.

French French French French Irish Scottish Irish Irish Norw Norw Portuguese Trwlers Trwlers Trawlers Trwlers trawlers Trawl Longline Longline longline comm. longline area V area area VI area VII surveys surveys fishery surveys Longline fishery VII XII VII VII area IX * VI XII XII Kg/h Kg/h Kg/h Kg/h Kg/h n/h Kg/h Kg/1000 Kg/1000 Kg/1000 Kg/1000 hooks hooks hooks hooks 1990 1991 1992 1993 1994 56 42 59 59 1995 46 27 48 48 1996 68 25 49 49 1997 34 30 46 46 158 1998 35 26 54 54 1999 26 21 55 55 107 83 87 2000 23 40 40 12 92 98 321 2001 18 40 40 21 78 52 337 2002 8 8 48 18 243 2003 4 16 15 311 2004 2 3 293 2005 1

* preliminary estimates

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12000 XIV XII 10000 X IX VIII 8000 VII VI 6000 Vb Va IV a 4000

2000

0 1988 1989 1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 2003 2004

Figure 3.1 - Total landings of of siki shark within the ICES area 1988-2004.

12% F (50) 10% M (73) 8%

0% 70 80 90 100 110 120 130 140 Length class (cm)

10% F (68) 8% M (123)

0% 70 80 90 100 110 120 130 140 Length class (cm)

Figure 3.2 - Length frequency distributions for each sex based on samples collected from landing of the Portuguese longliner fishery: 2002 (upper) and 2003 (lower)

ICES WGEF Report 2005 | 51

12%

10%

8% F (209) 6% M (71) 4%

0% 71 79 87 95 103 111 119 Length class (cm)

12%

10%

8% F (551) 6% M (150) 4%

0% 71 79 87 95 103 111 119 Length class (cm)

Figure 3.3 - Length frequency distributions for each sex based on samples collected from landing of the Portuguese longliner fishery: 1999 (upper) and 2000 (lower)

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C. coelolepis 100% C. squamosus

80%

60%

40%

20%

0% 1993 1995 1997 1999 2001 2003 2005 Year

Figure 3.4 - Relative proportion of the Portuguese dogfish and leafscale gulper shark in French landings (Data from 2004 must be regarded as preliminary).

C.squamosus

100

60 1994 50 1995 1996 40

0 jan fév mar avr mai jun jul aoû sep oct nov déc Date 199 199 199 jan 67Date 60 fév 50 80

Figure 3.5 - Monthly relative proportion of the Leafscale gulper shark in French “Siki” landings (Data from 2004 must be regarded as preliminary).

ICES WGEF Report 2005 | 53

120.0 400.0

350.0 100.0

300.0

80.0 250.0

60.0 200.0

150.0 CPUE trawl (kg) hour) CPUE trawl 40.0 CPUE longline (kg/1000 hooks) CPUE longline (kg/1000 100.0

20.0 50.0

0.0 0.0 1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005

French Trawlers area V French Trawlers area VII French Trwlers area VI French Trwlers area XII Irish trawlwers VII Scottish trawlsurveys Vi Irish Longline surveys VII Irish Longline fishery VII Norwegain longline surveys Norw Longline surveys Portugues longline fishery

Figure. 3.6 - C. coelolepis. CPUE series from trawls fisheries, longline fisheries and surveys.

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70.0 250.0

60.0 200.0

50.0

150.0 40.0

30.0 100.0 CPUE trawlCPUE (kg)hour) 20.0 CPUE longlineCPUE (kg/1000hooks) 50.0 10.0

0.0 0.0 1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005

French Trwlers area V French Trwlers area VII French Trwlers area VI French Trwlers area XII Irish trawlwers VII Scottish trawlsurveysVI Irish Longline surveys VII Irish Longline fishery VII Norwegain longline surveys Norw Longlinefishery Portugues longline fishery area IX

Figure. 3.7 - C.squamosus. CPUE series from trawls fisheries, longline fisheries and surveys.

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6000

5000 quota 2003 4000

3000 Ton

2000

1000

0 UK France Portugal Spain Germany Ireland Norw ay Lithuania Estonia Poland (mean)

Figure. 3.8 - Current quota and WG estimates of landings in 2003.

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4 Other deepwater sharks from the northeast Atlantic (ICES Subareas IV–XIV)

The present chapter includes miscellaneous information about other deep-water species with reported landings from ICES areas (I–XIV). In general, these species exhibit lower commercial value than the species dealt in the previous chapter, namely, Portuguese dogfish and leaf-scale gulper shark. Little information exists on the majority of the species presented here besides the annual landings composition data.

The species and generic landings categories (includes more than one species) presented are:

Gulper shark (Centrophorus granulosus), birdbeak dogfish (Deania calceus), longnose velvet dogfish (Centroscymnus crepidater), black dogfish (Centroscyllium fabricii), velvet belly (Etmopterus spinax), blackmouth catshark (Galeus melastomus), lantern sharks NEI (Etmopterus spp.) and ‘aiguillat noir’.

4.1 The fishery

4.1.1 Advice and management applicable ACFM has never provided advice for other deep-water species stocks.

Annual fishing opportunities in European Community waters zones and in certain non Community waters for stocks of deep-sea species were fixed for 2005 and 2006 (CR (EC) No 2270/2004 of 22 December 2004). Fishing opportunities for stocks of other deep-sea shark species for Community vessels were presented in Annex part 2 of CR (EC) no. 2270/2004. In this Annex are indicated by ICES sub-area the possibilities for fishing ‘Deep sea sharks’. This group refers to many shark species addressed in this chapter, including Birdbeak dogfish (Deania calceus), Velvet belly (Etmopterus spinax), Black dogfish (Centroscyllium fabricii), Gulper shark (Centrophorus granulosus) and Blackmouth catshark (Galeus melastomus).

4.1.2 Description of the fishery

Subareas IV, V, VI, VII, VIII and XII)

Most of the fisheries taking deep-water elasmobranch species are described in the previous chapter dealing with the Portuguese dogfish and leaf-scale gulper shark.

Divisions IXa and X

Gulper shark This species was the main target of a directed longline fishery for deep-water sharks, which started in 1983 at Viana do Castelo port in northern Portugal (STCEF, 2003). The fishery operated in grounds off the northern coast of mainland Portugal and west of the Galician coast. The landings predominantly consisted of gulper shark, with leafscale gulper shark and Portuguese dogfish caught in relatively small quantities. In the early years of the fishery, only the livers of the sharks were of commercial value and the carcasses were discarded at sea. Fishermen then started to process part of the catches on board to increase the value of the fish that is landed. In more recent years only one longliner has fished full time.

Gulper shark is occasionally captured by the deep-water fishery for black scabbardfish operating in the Portuguese continental slope.

Other species The other deep-water species are captured by artisanal longline fisheries operating in ICES sub-areas IX and X. Reference to these fisheries is made in chapter 3. A deep-water crustaceans trawl fishery operating in the Portuguese continental deep-water slope also captures species such as birdbeak dogfish, black mouth catshark and lantern sharks.

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4.2 Biological composition of the catch

An overall resume of the total landings (in tonnes) from each species, reported by country and by ICES division, for the period 1990 to 2004 is given in Table 4.2.1. Some of the data presented in the tables were compiled from FishStat Plus database for 1973 – 2003 (Figures in grey). No landings statistics reported by UK (E&W) are presented. These quantities are included in landings tables from chapter 3, as well as relevant comments to the quality of the data.

Gulper shark

Four European countries have reported landings: Ireland, UK, Spain and Portugal.

Ireland reported very few landings and only for the last two years. These values are from subarea VII. The landings data presented from Spain were retrieved from the FishStat Plus database (1973–2003). This country reported very few landings, having its highest annual value in 2002. Portugal presented landings for the period 1990–2004, having the highest values (>800 tonnes/year) between 1988 and 1993. The great majority of the Portuguese landings (>95%) came from division IXa.

Birdbeak dogfish

Three European countries have reported landings on Birdbeak dogfish: UK, Spain and Portugal.

Portugal presented landings from 2000 to 2004, with the highest value in 2004. All the reported Portuguese landings came from division IXa. The majority of Spanish landings are from sub-area XII, where values have been decreasing. No Spanish data are available for 2004.

Longnose velvet dogfish

Four European countries have reported landings: UK, France, Spain and Portugal.

Landings of in the ICES area have been higher for the last two years. France reported landings from almost every sub-area/ division considered, however, the figures were very low. Portugal reported very few landings from division IXa. Spain presented annual values over 50 tonnes / year in sub-area XII in 2000 and 2001, but after that no data were made available.

Black dogfish

Four European countries have reported landings on Black dogfish: Iceland, France and Spain.

France has reported the majority of the landings on black dogfish in the ICES area. This country has started to report landings in 1999. French annual landings on the species have decreased from about 250 tonnes in 2000 to nearly 30 tonnes in 2004. These landings are mainly from division Vb and sub-area VI. Iceland presented very few landings, being all from division Va. The largest annual landings reported by Spain came from sub-area XII in 2000 (85 Tonnes) and 2001 (91 Tonnes).

Velvet belly

Three European countries have reported landings on Velvet belly: Denmark, UK (E&W) and Spain.

Denmark has reported the majority of the landings on black dogfish in the ICES area from 1992 to 2002. All these landings refer to division IVa. Spain has reported few landings from sub-area VII (< 15 tonnes/year), but reported 85 tonnes in 2002 from sub-area VIII.

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Blackmouth catshark

Three European countries have reported landings on Blackmouth catshark: Iceland, Spain and Portugal.

Ireland has reported very few landings on this species (<= 1 tonne/year) and only for 2003 and 2004. Spain presented landings from several subareas, however, most of them refer to subarea VIII. The quantities reported were low, less than 10 tonnes / year. Portugal reported landings on Blackmouth catshark from 1990 to 2004. More than 98% of these landings came from division IXa. The annual landing values have ranged from 16 to 51 tonnes.

Lantern sharks NEI

Three European countries have reported landings on Lantern sharks NEI: France, Spain and Portugal.

France was the country that reported the majority of annual landings values between 1994 and 1998. However, these have largely decreased in the following years to less than 1 tonne. Sub- areas VI and VII have accounted for most of these figures. Portugal presented very few landings (only from Division IXa) throughout the all period (< 1 Tonne/year), reaching its maximum value in 2004 (55 Tonnes). Spanish landings reported were mainly from Subarea XII. In this sub-area, Spain reported 38 tonnes in 2000 and 317 tonnes in 2001. No information on Lantern sharks NEI from Spain and France is available for 2004.

Aiguillat noir This landings category is only used by France to register landings on small deepwater squalid sharks, including Black dogfish, Longnose velvet dogfish and Lantern sharks NEI. Division IVa accounted for the last majority of the French landings on ‘Aiguillat noir’. No more data was made available to WGEF since 2003.

Quality of catch and biological data

Gulper shark. Ireland, UK (E&W), UK (Scotland) and Portugal provided official landings data to the WGEF. UK (E&W) landings probably correspond to misidentifications of leaf-scale gulper shark or Portuguese dogfish (J. R: Ellis, personal communication). As referred before, these landings are presented in Tables from chapter 3.

Birdbeak dogfish. UK (E&W), UK (Scotland) and Portugal provided official landings data to the WGEF.

Longnose velvet dogfish. UK (E&W, Scotland), France, and Portugal provided official landings data to the WGEF.

Black dogfish. France provided official landings data to the WGEF.

Velvet belly. UK (E&W) provided official landings data to the WGEF.

Blackmouth catshark. Ireland, Spain (Basque country) and Portugal provided official landings data to the WGEF.

Lantern sharks NEI. Portugal provided official landings data to the WGEF.

‘Aiguillat noir’. No more data was made available to WGEF since 2003.

Length and age frequencies

Blackmouth catshark. There is information available from the Portuguese continental coast and west of Ireland.

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4.3 Fishery-independent information

Groundfish surveys

Blackmouth catshark. There is information from IPIMAR deep-water surveys in the Portuguese continental coast.

4.4 Catch per unit of effort

Blackmouth catshark. There are some CPUE data available from Norway and Ireland.

4.5 Discards

Birdbeak dogfish

There is some information published in a paper by Clarke et al. (2002) for the west and north of Ireland. The percentage discard rate was higher on the southern slopes of the Rockall Trough and on the southwestern slopes of the Porcupine bank. Discards must be considerable.

Blackmouth catshark

There is information included in the final report of the ‘Deep-water fisheries’ FAIR EC CT 95-0655 research project. Data was obtained from the Norwegian deep-water longline fishery for Ling (Molva molva) and Tusk (Brosme brosme) for the period 1995–1997. Blackmouth catshark was one of the major discarded species in divisions IVa and VIa. There is also information from the west of Ireland, but it was not presented to this Working group.

Other species

No information available for the ICES area.

4.6 Mean length, weight, age, maturity, natural mortality

Birdbeak dogfish

Northwest of Ireland. There is some information on length frequencies, age and maturity

published in a paper by Clarke et al. (2002). TL50 for males: 85 cm; TL50 for females 105 cm.

Portuguese continental slope. There is information on age determination in a paper by Machado and Figueiredo (2000).

Blackmouth catshark

Portuguese continental slope. There is a study on age determination using vertebrae by Correia and Figueiredo (1997).

Black dogfish

There is information for the west of Greenland waters (Yano, 1996). Size at maturity: Males (550 mm TL) and Females (650 mm TL).

Other species

No information available for the ICES area.

4.7 Stock assessment

Blackmouth catshark

Though it was one of the nine case-study species considered in the DELASS EU project, the lack of data available has been preventing stock assessment studies. However, abundance indices were calculated for two regions in the Portuguese continental slope (Table 4.7.1), Algarve (south) and Alentejo (west), based on data from deep-water surveys conducted by

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IPIMAR in the summer months (ICES, 2002b). The period considered ranged from 1990 to 2001. In the Algarve region, its abundance has fluctuated over the last decade without any marked trend, and its abundance off Alentejo has been stable throughout the series.

Table 4.7.1 - Mean annual density values ( 10-3 kg/ mn2) of blackmouth catshark in two different regions of the Portuguese continental slope (Algarve and Alentejo).

Region Year Algarve Alentejo 1990 0,36 0,93 1991 0,29 0,37 1992 0,51 1,55 1994 0,30 1,70 1995 0,44 1,70 1997 0,41 n.a. 1998 0,49 n.a. 2001 0,35 n.a. Other species

No assessment studies were conducted so far.

4.8 Stock status

Blackmouth catshark

In the SGEF 2002 report (ICES, 2002a) it was referred that may be reasonable to nominate two stocks, one off the Portuguese continental coast and one in Subareas VI/VII, nevertheless, there is still insufficient data available to distinguish between them. It is possible that blackmouth catshark populations are essentially local (like Lesser spotted dogfish), with one large population in which pseudo population segments can be distinguished (ICES, 2002a).

Other species

No information available.

4.9 Reference points

No reference points have been proposed for any of these species stocks.

4.10 Quality of the assessment

No assessment studies were conducted so far.

4.11 Management considerations

In the contnnetal slopes of Euurope these species should be managed in a multi-species context with particular attention to the management of leafscale gulper shark and Portuguese dogfish (Section 3).

Gulper shark

The species is listed under the I.U.C.N. Shark Specialist Group Red List as Vulnerable to exploitation. The species has low resilience with a minimum population doubling time from 4.5 to 14 years (FishBase).

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Table 4.2.1 - Landings data of other deep-water species by country and ICES division. Species Division Country 1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 IV UK (Scotland) +++++++++++++8n.a. V UK (Scotland) +++++++++++++30n.a. VI UK (Scotland) +++++++++++++18n.a. Ireland +++++++++++++ 2+ VII UK (Scotland) +++++++++++++2n.a. VIII Portugal +++++++++ 3+3718n.a.

Gulper shark Gulper Portugal 1056 801 958 886 344 423 242 291 187 92 54 93 148 166 83 IXa Spain ++++++++++++ 8+n.a. XPortugal ++++++++++++ 419n.a. Spain ...... ++n.a.n.a.n.a. VI UK (Scotland)...... 1+12 Spain ...... ++ 5+n.a. VII UK (Scotland)...... +++ 236 VIIISpain ...... ++ 5+n.a. IXaPortugal ...... 13376772146 Birdbeak dogfish Birdbeak XIISpain ...... 1252+ n.a. IVFrance ...... +n.a VFrance ...... ++ + 331 France ...... ++ + 542 VI Spain ...... ++n.a.n.a.n.a. UK (Scotland)...... ++++21 7 France ...... +++ VII UK (Scotland)...... + IXaPortugal ...... 134 21

Longnose velvet dogfish velvet Longnose France ...... ++ XII Spain ...... 8568n.a.n.a.n.a. IVFrance ...... +148+ +. France ...... +123 101 10 36 9 V Iceland . . 1 . . 1 4 . . . . . ++n.a France ...... + 130 128 24 17 19 VI Spain ...... 1+n.a.n.a.n.a. VIIFrance ...... + 471++ VIIIFrance ...... + Black dogfish Black France + 32+1+ XII Spain . 84 91 n.a. n.a. n.a. IV Denmark . . . 27 + 10 8 32 359 128 25 52 . . . VIISpain ...... 3n.a.n.a.

V. belly VIIISpain ...... 82n.a.n.a. VISpain ...... 1+n.a... Ireland ...... +1 VII Spain ...... ++ + +9+n.a. Spain (Basque c.)...... +.+...+ Portugal ...... 12.n.a. VIII Spain ...... 4 3 623 1111 Portugal 17 17 16 20 37 29 35 29 22 23 35 35 50 29 51 IXa Spain ++++++++++++25+n.a. Blackmouth catshark Blackmouth XPortugal ...... 4 . ++. IV France . . . . . 17 23 . 26 +. + ++n.a Vb France . . . . 51 159 213 167 218 +. + ++n.a France . ... 343 1480 2039 1620 1355 + . + + + n.a VI Spain ...... +21n.a.n.a.n.a VIIFrance . ... 452 647 524 344 379 + . + + + n.a France ...... 31+.+++n.a VIII Spain . ... ++++++++91+n.a Portugal ....++++..+...55 IXa

Lanternsharks NEI Spain . ... ++++++++ 8+n.a. France . ... . 85 89 19 34 + . +++n.a XII Spain ...... 38317n.a.n.a.n.a r IVaFrance ...... 127120n.a.n.a.n.a. VbFrance ...... 14.n.a.n.a. VIIFrance ...... 46.n.a.n.a.

Aiguillat noi XIIFrance ...... 32.n.a.n.a. Total All All 1073 818 975 933 1227 2851 3181 2505 2617 248 751 1147 565 453 414

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5 Kitefin shark (entire ICES area)

There is still a lack of data that can accurately identify any different stocks of kitefin shark in the NE Atlantic. Nonetheless, Hareide and Garnes (2001) suggested that the species mainly occurs in ICES Sub-area X. For the assessment purpose the Azorean stock was considered as a management unit (ICES Subarea X).

5.1 The fishery

5.1.1 Advice and management applicable to 2003 and 2004

ACFM has never provided advice for this stock.

The kitefin shark, along with deepwater other sharks is subject to management in Community waters and in certain non Community waters for stocks of deep-sea species for 2005 and 2006 (EC no 2270/2004 article 1). Fishing opportunities for stocks of deep-sea shark species for Community vessels were presented in an Annex (EC no 2270/2004 article 3) (Table 3.1). A list of species was given to be considered in the group of ‘deep sea sharks’.

The TAC for V, VI, VII, VIII and IX for this and these species is 6763 t. In Subarea X the TAC is 14 t.

5.1.2 The fishery in 2004

Detailed descriptions of fisheries are presented in ICES (2002a) and Heessen (2003). As reported last year, the only new information that is available relates to gillnet fisheries for this species reported for the 2003 year. Gill-net vessels registered in the UK (England and Wales), UK (Scotland) and Germany, target this and other deepwater species. This fishery has been in operation since the mid 1990’s and takes place mainly west of the British Isles (Sub-areas VI and VII). These fisheries are described on the DEEPNET project report made available to the working group (Hareide et al., 2004). Kitefin from the Azores is now a by-catch from different deep-water fisheries, with a very low landing of 6.4 t during 2004 (Pinho, 2005).

The catches reported from each country, for the period 1988 to 2004 are given in Tables 5.1, 5.2 and 5.3 and total historical catches from 1988 to 2004 in Figure 5.1.

5.2 Biological composition of the landings

5.2.1 Catch in numbers

There is no length or age composition of the catch available for this stock. Available information on fishery length composition was reported by Silva (1988).

5.2.2 Quality of catch and biological data

Deepwater sharks taken in the Azores are usually gutted, finned, beheaded and also skinned. Only the trunks and, in some cases, the livers are used. Whenever these fish are landed, the real weight of the catch is clearly underestimated. Data from observers or fishing logbooks are not available. Species misidentification happens mostly with deepwater sharks. Official Landings come exclusively from the commercial first sale of fresh fish on the auctions. Landings that are not sold on the auctions, as the freeze fish, are not taken in account on the statistics provided to ICES.

There is no biological sampling of the landings. Biological data from the fishery were not collected in a systematic way over time and available data were reported by Silva (1988). Few individuals are caught and sampled on demersal surveys (only 25 individuals were caught from 1995 to 2004), because the gear configuration was not designed to target this species.

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5.3 Fishery-independent information

There is a spring demersal bottom longline survey running on the Azores annually (Subarea X). However, very few kitefin sharks have been caught on this survey because the gear configuration is not design for this species.

5.4 Mean length, weight, maturity and natural mortality-at-age

Mean weight and length by age are available from growth curves estimated by sex from data collected during the period 1982–1987 (Silva, 1988). However, there are no annual data on the composition of the catch.

5.5 Recruitment

Only mature females (gonad running, pregnant or resting) and males (sperm running from the claspers and resting) were observed in the Azores. Individuals less than 98 cm are not observed on the region suggesting that probably spawning and juveniles occurs in deep water or non- exploited areas. Males kitefin shark are more available to the fishery at 100 cm (age 5) and females at 120 (age 6).

5.6 Stock assessment

5.6.1 Previous assessments of stock status

Stock assessments of kitefin fishery were made, using equilibrium Fox production model (Silva, 1987). The stock was considered intensively exploited with the average observed total catches (809 t) near the estimated maximum sustainable yield (MSY=933 t). An optimum fishing effort of 281 days fishing bottom nets and 359 man trips fishing with hand lines were suggested, correspondent approximately to the observed effort.

During the DELASS project (Heessen, 2003) a Bayesian stock assessment approach using three cases of the Pella-Tomlinson biomass dynamic model with two fisheries (handline and bottom gillnets) was performed (ICES, 2003).

5.6.2 Data exploration and preliminary modelling

Assessment of the species status was not done during this WGEF meeting since no new data were available.

5.6.3 Stock Assessment

The methodology and results of the assessment on the kitefin shark presented in this section constitute a summary of the work developed by Silva et al. (2003) for the DELASS project (Heessen, 2003).

The Pella and Tomlinson (1969) model was fitted to time series of catch rates for Azorean kitefin shark handline (1977–1996) and gillnet fisheries (1980–1998) (Table 5.4). It was assumed that CPUE is proportional to abundance and that the observation errors are lognormally distributed. It was also assumed that the population was at the virgin equilibrium levels (B0) at the start of 1972, which seems plausible since the exploitation started in the early 1970s with very low catch levels taken only by the artisanal fishery.

The uncertainty of the curvature of the surplus production model was explored by fixing m at three different values (m= 1.0, 2.39 and 5.49). These values correspond to case studies where the maximum sustainable yield (MSY) occurs respectively at 50% (Schaefer model – the base case), 60% and 70% of the virgin biomass (the population’s carrying capacity K). Bayesian approach was adopted and no informative distribution was adopted for K and two gear

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catchability parameters. The prior distribution adopted for r was derived from the results of the demographic analysis, which incorporated the biological information from Silva (1988). Posterior distributions were computed, using Sample-Importance-Resample (SIR) algorithm, for the free parameters in the model (r, K, qh and qg) and three quantities of interest: biomass

at the start of 2001 (B2001), depletion level at the start of 2001 (B2001/B0) and maximum sustainable yield, MSY.

Risk analysis was performed and assuming the achieved MSY as the reference point. Forward population projections until 2010 were made for each model case studied (i.e., the three different curvature shapes of the surplus production curve considered). Five different levels of a constant catch policy were applied: 1) no catch; 2) 250 t; 3) 500 t; 4) 750 t; and, 5) 1000 t. Posterior distributions were generated for the following quantities of management interest:

biomass at the start of 2010 (B2010), proportion of the biomass in 2010 with respect to the

biomass at the start of 2001 (B2010/B2001) and depletion at the start of 2010 (B2010/B0).

5.7 Stock and catch projection

The Maximum Likelihood Estimation (MLE) carried out for the three different cases of the Pella-Tomlinson biomass dynamic model (m = 1.0, 2.39 and 5.49) gave unrealistic values for the intrinsic rate of population increase (r). This problem is illustrated in Figure 5.2 for the base case (m=1 Schaefer model). The Bayesian approach in which the prior assigned to r was derived from the demographic analysis output gave posterior distributions for r and K that fall into a narrow probability area where r-parameter values are restricted to positive space and are biologically consistent with the life-strategy of a shark (Figure. 5.3). Posteriors on r and the two catchability parameters were not sensitive to the three values of the m-parameter considered in the Pella-Tomlinson model. Posterior obtained for the carrying capacity (K) were strongly skewed to the right and slightly sensitive to m (Figure 5.4). As a result, the different case study models predict the same history pattern for the biomass dynamics, though the exploitation starts at slightly different K equilibrium levels (Figure 5.5).

Predicted time-series of biomass showed a continuous decline through the 1970s and 1980s when the exploitation was productive and profitable. During the 1990s, and following the gradual decline of the fishery due to market reasons.

As expected, the posterior for MSY is sensitive to the m curvature parameter, with the base case model (m = 1; Schaefer) allowing the highest MSY (posterior median of 219 t). Posteriors for MSY are skewed to the right, consistent with the uncertainty pattern of K. The probability of the stock to be overexploited (P(B2001>BMSY)) was 51% for m=1, 71% for m=2.39 and 85% for m=5.49 (Table 5.5).

The analysis of the risk consisted on projecting forward the kitefin shark population biomass under 5 different constant catch policies (no catch, 250 t, 500 t, 750 t and 1000 t per year). The risk curves are shown in Figure 4.5.4. Assuming Schaefer model (m = 1) and a constant no catch fishing policy the probabilities for the stock size to recover to MSY levels are 0.63 and 0.75, by 2006 and 2010 respectively. For the same model, a constant catch policy of 250 t will reduce these probabilities to approximately 0.50. Alternatively, a constant catch exceeding 250 t represents a risk of more than 50% that the stock will not attain MSY levels either by 2006 or 2010. The same risk level is associated for the other two models analysed (m = 2.39 and m = 5.49), regardless of the catch policy adopted.

5.8 Reference points

The highest posterior MSY median estimated was 219 t for the base case Schaefer option (m=1). Under this model option was found that the probability of the stock being overexploited (P(B2001

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5.9 Quality of the assessment

The assessment carried out on the kitefin shark has shown severe declines and suggests that the stock may be depleted. According to the data from the handline and gillnet fisheries the abundance of the species declined in the two periods analysed. This decline is interpreted as a real decrease on the population abundance. However, the catches and landings are likely to be influenced by market considerations, and fishery CPUE may not reflect real abundance trends, particularly in the last decade. This issue should be further investigated through the analysis of socio-economic data and its relation to CPUE temporal variation.

5.10 Management considerations

Preliminary assessment results show that the stock may be depleted. However, further analysis is required in to better understand the status of the stock, particularly analysing socio- economic aspects. The working group considers that the development of a fishery must not be permitted before data become available in order to have a more precise idea about the sustainable catch.

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Table 5.1 Total Landings (t) of Kitefin Shark Dalatias licha Subareas Vb, VI, VII, IX Country 1988 1989 1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 200 UK 39 (Scotland) UK (E+W) 51 Portugal 149 57 7 12 11 11 11 7 4 4 6 14 282 176 5 11 Total of Submitted 149 57 7 12 11 11 11 7 4 4 6 14 282 176 5 67 Data

Table 5.2 Total Landings (t) of Kitefin Shark Dalatias licha Subarea X Country 1988 1989 1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 200 Portugal 549 560 602 896 761 591 309 321 216 30 34 31 31 13 35 25 (Azores) Total of Submitted 549 560 602 896 761 591 309 321 216 30 34 31 31 13 35 25 Data

Table 5.3. Annual landings of kitefin shark by ICES statistical area. Landings data in V, VI and VII considered overestimates.

Year X IXa VII VI Vb 1988 549 149 1989 560 57 1990 602 7 1991 896 12 1992 761 11 1993 591 11 1994 309 11 1995 321 7 1996 216 4 1997 30 4 1998 34 6 1999 31 6 8 2000 31 5 277 2001 13 7 169 2002 35 5 2003 25 3 332 315 25 2004 6 1

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Table 5.4. Catch and CPUE data for the kitefin shark fishery in the Azores by fleet component (bottom gillnet and handline fleets). Total catch values can exceed sum of both fisheries because it includes by-catch of other fisheries or from unknown sources. Line in the year 1976 denotes a learning period of the fishery. Table is updated from 2001 to 2004 with total catch.

Handlines Bottom gillnets Total Average Catch CPUE Catch CPUE Catch Price/kg (t) (Euro) (t) (kg/man/day) (t) (kg/net/day) Year Mean cv Mean cv

1972 14.7 72.58 1.98 14.7 0.016 1973 22.3 102.8 0.98 22.3 0.015 3 1974 161.4 142.5 1.34 161.4 0.023 4 1975 97.4 176.9 1.10 97.4 0.020 5 1976 11.8 166.2 0.96 11.8 0.019 2 1977 153.9 224.3 0.92 188.0 0.025 2 1978 196.4 260.4 1.27 196.4 0.043 4 1979 232.7 214.5 1.85 232.7 0.079 7 1980 226.5 181.5 1.34 396.1 27.22 0.47 658.4 0.127 9 1981 173.7 119.4 0.92 667.2 9.85 1.27 947.0 0.154 4 1982 59.6 121.8 0.92 81.9 9.48 0.72 141.6 0.128 1 1983 90.9 112.8 0.84 83.4 17.57 0.62 220.3 0.344 7 1984 95.2 71.95 1.93 842.0 36.59 1.26 937.4 0.395 1985 73.8 80.27 1.21 814.4 55.52 0.84 902.5 0.323 1986 63.5 127.6 1.13 663.0 53.62 0.73 741.0 0.389 3 1987 117.9 156.8 1.02 290.3 41.52 0.78 413.2 0.303 5 62.6 105.2 0.89 443.3 79.61 0.63 548.9 0.341 6 1989 105.8 187.5 1.24 452.1 72.99 0.61 559.8 0.356 6 1990 100.9 103.9 0.92 492.0 83.85 0.48 601.8 0.404 4 1991 87.6 104.2 1.10 793.9 79.96 0.53 896.3 0.486 8 1992 64.3 86.46 0.90 672.2 23.37 0.98 760.8 0.788 1993 40.9 178.9 1.40 550.4 33.14 0.56 591.3 0.511 2 1994 49.8 104.6 1.10 258.7 41.39 0.69 309.0 0.562 6 1995 51.1 175.4 0.79 269.4 36.81 0.58 320.9 0.386 8 1996 68.4 243.4 1.14 147.7 29.22 0.51 216.4 0.501 6 1997 29.9 121.8 23.61 1.11 151.9 0.521 1998 29.9 6.3 22.49 0.86 40.4 0.582

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1999 23.6 31.3 0.405 2000 22.8 0.1 31.0 0.325 2001 10.6 0.9 12.7 0.347 2002 35.2 0.368 2003 24.8 0.322 2004 6.4 0.445

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Table 5.5. Descriptive statistics of the Bayesian posteriors for model parameters and quantities of management interest. Also, the probability for the stock size in 2001 to be greater than the MSY stock biomass (P(B2001>BMSY)) is also given for each model case.

Model parameters Quantities of interest P(B2001

Base-case (m = 1, Schaefer) 0.51 10% lower bound 0.043 10681 0.006 0.002 3153 28.5 151 50% median 0.063 13768 0.015 0.007 6696 49.2 219 90% upper bound 0.085 26927 0.027 0.012 20884 78.0 422 Mean 0.064 16412 0.016 0.007 9535 51.2 258 m = 2.39 0.71 10% lower bound 0.043 11553 0.006 0.002 2866 24.7 113 50% median 0.065 14879 0.014 0.006 7175 47.5 171 90% upper bound 0.087 29105 0.024 0.011 23464 78.6 320 Mean 0.065 17534 0.015 0.007 9955 49.5 199 m = 5.49 0.85 10% lower bound 0.042 12342 0.005 0.002 2897 23.3 70 50% median 0.063 16076 0.012 0.005 7315 45.1 112 90% upper bound 0.084 30695 0.022 0.010 23255 76.6 207 Mean 0.063 18769 0.013 0.006 10187 47.4 128

1000 900 800 700 600 500 400

Landings (mt) 300 200 100 0 1988 1990 1992 1994 1996 1998 2000 2002 2004 Year

UK (Scotland) UK (Scotland) UK (E+W) Portugal UK (E+W) Portugal Portugal (Azores)

Figure 5.1 Total catch of kitefin by ICES statistical areas. 70 | ICES WGEF Report 2005

Figure 5.2 – Joint likelihood surface of r and K for the base case model (m = 1; Schaefer model). Catchability coefficients fixed at MLE.

Figure 5.3 – Joint posterior surface of r and K for the base case (m = 1; Schaefer model). Calculated using the grid search method (see Punt and Hilborn, 2001).

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0.14 0.25

0.12 0.20

0.10

0.15 0.08

0.06 0.10 Probability Probability 0.04 0.05 0.02

0.00 0.00 0.00 0.02 0.04 0.06 0.08 0.10 0.12 0.14 0 10,000 20,000 30,000 40,000 50,000 Intrinsic rate of increase, r Karrying capacity, K (x103 kg)

0.18 0.35

0.16 0.30 0.14 0.25 0.12

0.10 0.20

0.08 0.15 Probability 0.06 Probability 0.10 0.04 0.05 0.02

0.00 0.00 0.000 0.005 0.010 0.015 0.020 0.025 0.030 0.035 0.040 0.045 0.050 0.000 0.005 0.010 0.015 0.020 0.025 0.030 0.035 0.040 0.045 0.050

Catchability handlines, qh Catchability gillnets, qg

0.14 0.30

0.12 0.25

0.10 0.20 0.08 0.15 0.06 Probability Probability 0.10 0.04

0.05 0.02

0.00 0.00 0 100 200 300 400 500 600 700 800 900 1,000 0 5,000 10,000 15,000 20,000 25,000 30,000 35,000 40,000 45,000 50,000 Maximum sustainable yield, MSY Start 2001 biomass (x103 kg)

0.15 0.12 0.10

0.10 0.05 m = 1

0.08 0.00 0 50 100

0.06 m = 2.39 Probability 0.04

0.02

m = 5.49 0.00 0 102030405060708090100

Depletion, B2001/B0 (%)

Figure 5.4. Bayesian marginal posterior distributions for model parameters (r, K, qh and qg) and quantities of management interest (MSY, B2001 and B2001/B01). Posteriors are presented for each Pella-Tomlinson case study model analyzed (m = 1, 2.39 and 5.49).

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18,000

16,000

14,000

12,000 m = 1 10,000 m = 2.39 8,000 m = 5.49 6,000 Biomass (mt)

4,000

2,000

0 1972 1976 1980 1984 1988 1992 1996 2000 Year

Figure 5.5. Time series of biomass predicted by the three case studies of the Pella-Tomlinson models considered (m = 1, 2.39 and 5.49). Lines represent median values of posteriors.

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6 Porbeagle in the North East Atlantic (Sub-areas I-XIV)

The DELASS project (Heessen, 2003) considered that a single stock of porbeagle occurs in the northeast Atlantic, hence in the entire ICES area. There is a separate northwest Atlantic stock.

6.1 The Fishery

Advice and Management Applicable to 2003 and 2004

ACFM has never provided management advice for this stock. However ICES was asked to advise on a German proposal to add this species to the CITES Appendix II.

There are no management measures in place for this species. Since December 2004, it’s forbidden in Sweden to land porbeagle caught in Swedish waters.

The fishery until 1999

Porbeagle sharks have often been taken as a by-catch in trawls, seines, pelagic and bottom gill nets and by surface longlines set for billfish and tunas.

The porbeagle (Lamna nasus) has been exploited commercially since the early 1800s, principally by Scandinavian fishermen. This includes most of the ICES area, especially Skagerrak (IIIa), North Sea (IVa–c), the Faeroes (Vb), English Channel (VIId–e), Celtic Sea and south-west Ireland (VIIg–k), Bay of Biscay (VIII) and Portugal Mainland and Azorean waters (IX and X). Smaller numbers are also taken from the Norwegian Sea (IIa), Iceland (Va), west coasts of Ireland and Scotland (Via–b and VIIb–c), the Irish Sea (VIIa) and Bristol Channel (VIIf). Landings off Spain have tended to be greater during the spring and autumn, with a drop in the summer (Mejuto, 1985; Lallemand-Lemoine, 1991).

Traditional line fisheries directed at porbeagle (which also takes occasional tope and blue sharks) in the northern North Sea and off the Scottish coast have involved specialised vessels from Norway and, to a lesser extent, Denmark and the UK, and French vessels fishing to the south and west of England.

Prior to 1930, the Norwegian fleet used shark lines in the eastern North Sea, mainly during July–October. Over the period 1930–1965, Norway was the principal country fishing for porbeagle, and it extended the fishery to the Orkney-Shetland area and the Faeroes and then to the waters off Ireland and offshore banks by the 1950s. Landings by Norway first reached a peak of 3884 t in 1933, and about 6000 t were taken by the Norwegian fleet in 1947, when the fishery reopened after the Second World War.

A progressive drop in Northeast Atlantic landings followed from 1953–1960, to around 1200– 1900 t annually. In 1961, a fleet of Norwegian longliners extended their fishing for porbeagle to Northwest Atlantic waters off the coast of New England and Newfoundland. Catches of porbeagle had declined by 1965, when many of the vessels switched to other species or moved to West African grounds to fish for mako shark and swordfish (Gauld, 1989).

Norwegian landings from the Northeast Atlantic continued to decrease from 160–300 t/annum in the early 1970s to around 10–40 t/annum in the late 1980s/early 1990s.

The Norwegian and Faroese fishery shifted effort to the NW Atlantic stock from the 1970’s onwards, as the stock in the NE Atlantic became unprofitable. This demonstrates that the stock in the NE had been depleted by this time.

Denmark’s small fleet of specialised shark longline vessels formerly operated in the summer months, predominantly in the North Sea but extended into the Northwest Atlantic in the 1980s

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(Gauld, 1989). Average landings from the Danish porbeagle fishery fell from 500–600 t/annum in the 1950s to under 50 t in 1984. More recently, a minimum of 32 t was landed by Denmark in 1988, rising to 94 t in 1994.

Porbeagles were reported in landings statistics by Scotland in the mid to late 1950’s (Rae, 1962; Gauld, 1989). The Faeroes, France, England, Iceland, Germany and Sweden started landing significant quantities in the 1970’s. French longliners have operated a directed fishery for porbeagle from Isle d’ Yeu, landing into La Rochelle (Lallemand-Lemoine, 1991). The main fishing grounds were in the Celtic Sea and Bay of Biscay, from where over 77% of the total French catch of 640 t recorded by all gears in 1993 was landed. Their activity is now decreasing. Similarly, local fisheries in the Bristol Channel occasionally deployed longlines for porbeagle (Ellis and Shackley, 1995).

The fishery 2000–2004

Available landing data are presented in Table 6.1 and data from 1952 to present day are presented in Figure 6.1.

Before 1970, mainly Norway, Denmark and the Faeroe Islands have reported landings of porbeagle, Iceland and Germany only reporting minor landings. The peaks in 1970–1972 and in 1978 mainly come from Spanish reporting landings – these were between 2000 and 4000 tonnes (see Figure 6.1). Between 1996 and 2001 Spain reported landings again.

5000 4500 4000 3500 3000 2500

Tonnes 2000 1500 1000 500 0 1952 1955 1958 1961 1964 1967 1970 1973 1976 1979 1982 1985 1988 1991 1994 1997 2000 2003

Year

. Figure 6.1 Available landings data for porbeagle. It is not clear if data are complete for any year.

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Table 6.1 Available landing data for porbeagle in ICES area. From FISHSTAT database. Must be considered an underestimate.

1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 Channel 15 14 1 + 2 2 2 Islands Denmark 46 85 80 91 94 86 71 69 85 107 73 76 42 Faeroe 14 7 20 76 48 44 7 9 7 10 13 8 10 Islands France 551 300 496 633 820 565 267 315 219 318 410 368 461 Germany 22 + 17 1 3 Iceland + + 1 3 4 6 5 3 4 2 2 3 2 Ireland 8 1 6 3 Norway 44 32 42 24 25 27 28 17 28 33 22 17 19 Portugal 2 1 6 2 Spain 31 124 679 1001 1184 1007 Sweden 2 2 4 3 2 2 1 1 1 1 1 1 + United 6 6 10 7 Kingdom Total 674 441 643 830 1015 730 410 538 1024 1486 1737 1501 549

40 000 35 000 30 000 25 000 20 000

Tonnes 15 000 10 000 5 000 0

1950 1953 1956 1959 1962 1965 1968 1971 1974 1977 1980 1983 1986 1989 1992 1995 1998 2001

Year

Figure 6.2 shows FISHSTAT data from Area 2 7- the NE Atlantic - for various sharks nei (=not elsewhere identified). The WGEF knows that the data contains landings of porbeagle, but have no knowledge about the exact amount. Before 1970 it is only Spain and Germany who have reported landings. Throughout the years, Spain stands for the major part of the landed sharks. Between the years 1970 and 1980, Spain didn’t report any landings of various sharks nei.

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Table 6.2 FISHSTAT data regarding catches of various species of sharks nei in the NE Atlantic.

1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 Belgium 23 22 19 20 19 18 11 14 15 18 12 Channel 42 43 32 30 2 3 3 7 1 - - Islands Denmark 5 5 3 4 ------Estonia ------53 Germany 2 133 440 292 309 139 110 - - - - Ireland - 17 16 40 23 32 169 90 175 455 496 Netherlands ------3 - Norway + - + + + 1 + 13 1 72 1 Portugal 618 1047 969 1853 1659 1874 1882 352 297 216 345 Spain 6551 6914 10998 18101 3642 30377 20450 23662 31793 30815 17771 United 1119 1393 1944 2339 2040 3865 2669 2342 954 1640 1198 Kingdom Total 8360 9574 14421 22679 7694 36309 25294 26480 33236 33219 19876

A particular problem with porbeagle is that some non-ICES member states fisheries are likely to catch the species but data are lacking. Such countries include Japan, Republic of Korea, Taiwan Province of China and possibly Uruguay (Figure 6.3, Table 6.3). The presence of porbeagle in catches from Japanese bluefin tuna longliners has been confirmed in international waters and Norwegian waters Hareide et al. (1999). This fleet of Japanese longliners consists

30 000

25 000

20 000

15 000 Tonnes 10 000

5 000

950 953 956 959 962 965 968 971 974 977 980 983 986 989 992 995 998 001 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 2 Year

of about 50 vessels in north Atlantic.

Figure 6.3 FISHSTAT data regarding catches of various species of sharks, rays, skates etc. nei in the NE Atlantic.

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Table 6.3 FISHSTAT data regarding catches of various species of sharks, rays, skates etc. nei in the NE Atlantic.

1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 20 France - 8 18 - - 2 ------Japan 62 91 107 174 168 376 132 108 211 72 35 82 Korea, Republic of ------Latvia 3 ------Poland ------11 Portugal 128 1387 1047 ...... 41 40 40 4 Russian Federation ------Sweden <0.5 <0.5 1 <0.5 <0.5 <0.5 <0.5 <0.5 <0.5 <0.5 <0.5 - Taiwan Province of - - - - - 22 15 15 - 10 14 8 2 China Un. Sov. Soc. Rep. ------Uruguay ------3 Total 193 1486 1173 174 168 400 147 123 211 123 89 141 3

6.2 Biological composition of the Catch

According to studies reported in Gauld (1989) it seems like the overall sex ratio is 1:1 in longline fisheries, although most different catches either contained a dominance of females or males.

6.3 Management considerations

There is insufficient information on the NE Atlantic stock. However the stock was depleted by the 1970’s and the directed fishery stopped at that time due to unprofitability. Sporadic small fisheries have continued to appear and disappear in various areas since that time. The high market value of this species means that a directed fishery would develop again if abundance increased. Therefore there is evidence that the stock has not recovered.

Effort has increased in recent years in pelagic longline fisheries for bluefin tuna (Japan, Republic of Korea and Taiwan Province of China). These fisheries take porbeagle as a by- catch.

The stock in the NW Atlantic is considered by WGEF to be likely to have similar biological parameters. WGEF considers that this stock is vulnerable to fishing pressure. Experience from the NW Atlantic indicates that fisheries can target spawning aggregations. Further information on the temporal and spatial distribution, population structure and movements and migrations of the NE Atlantic stock is required

A pelagic longline fishery for porbeagle in Canadian waters was first prosecuted by Norway and Faroe Islands in the 1960s–1990s. There is now only a limited fishery by Canada. A Management Plan was introduced by Canada in 1995 following a decline of the stock

There is no biological information on the stock in the NE Atlantic, but in Canada DFO (2001) concluded that the intrinsic rate of population growth in an unfished porbeagle population is 5- 7%. The current porbeagle population is seriously depleted and will require a greatly reduced fishing mortality if recovery is to occur. Recovery will not be rapid in such a low productivity

species. Fishing at F0.1=0.18 is unsustainable, and will result in stock collapse. The model suggested that fishing at F=0.08 resulted in a zero population growth, while a fishing mortality (F) of 0.04-0.05 should correspond to maximum sustainable yield (MSY) and is required if the population is to be allowed to recover (Campana et al. 2003). All estimates of recent fishing mortality (following introduction of management) were well above sustainable levels, ranging from 0.1 to 0.3, with the most reliable around F=0.2. An annual catch of 200–250 t would

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correspond to fishing at about MSY and would allow population growth. Annual catches of about 400 t would not allow any population growth, nor leave room for error in the estimates. However, annual catch levels of about 1 000t might be sustainable in the long term once the population has recovered.

Subsequently, COSEWIC (Committee on the Status of Endangered Wildlife in Canada - www.cosewic.gc.ca/) designated porbeagle as an “endangered” species in Canada in May 2004. The Department of Fisheries and Oceans is presently evaluating whether to place porbeagle on Schedule 1 of the Species at Risk Act (SARA) which would afford it legal protection. If a species is listed in Schedule 1, all activities affecting the species would be prohibited. Under Sect. 73(2) of SARA, authorization to allow harm may be issued if the activity relates to scientific research, benefits the species or is an incidental (non-directed) activity that does not affect recovery of the species. An Allowable Harm Assessment, presently under way, will define possible conditions that would allow human activity affecting porbeagle to occur.

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7 Basking Shark in the northeast Atlantic (ICES Areas I-XIV)

WGEF considers that a single stock of this species exists in the ICES area. There is no information on transatlantic migrations.

7.1 The fishery

7.1.1 Advice and management applicable

ACFM has never provided advice for this stock.

The current TAC for EU member states in EU waters of ICES Subareas IV, VI and VII is 0 (Annex ID of Council Regulation 2555/2001). This has been in effect since 2002.

In the past, Norway had a quota in EU waters for livers. The EU no longer provides for this entitlement.

In recent years the basking shark has become a protected species in the UK. UK legislation (Schedule 5 of the Wildlife and Countryside Act of 1981), does not allow basking to be caught within 12 miles of the coast and none landed even if caught outside territorial limits. They are also protected in Isle of Man waters. Basking shark is listed under Appendix II of CITES.

7.1.2 The fishery

Norwegian fishermen have always been the major catchers of basking sharks in the Northeast Atlantic. Their fisheries generally started around April and May, occasionally as early as March in some years, reached a peak in June and finished in August or, less commonly, September (Myklevoll, 1968). The fleet was composed of small wooden vessels 15 to 25 m in length, which are sometimes used for hunting small whales as well as basking sharks (Kunzlik, 1988). The geographical and temporal distribution of the Norwegian domestic basking shark fishery changed markedly from year to year, possibly due to the unpredictable nature of the sharks' inshore migration (Stott, 1982). The Norwegian fleet has prosecuted local fisheries from the Barents Sea to the Kattegat, as well as more distant fisheries ranging across the North Sea and as far afield as the south and west of Ireland, Iceland and Faeroes. Norwegian fishermen were fishing for porbeagle off the Scottish coast as early as 1934, and it is thought that they first started fishing there for basking sharks in the immediate post-war years after the establishment of several native Scottish fisheries. Similarly, Norwegian vessels took basking sharks in Irish waters following the establishment of Irish fisheries there after the Second World War. During 1959–1980, catches ranged between 1266 and 4266 sharks per year, but have since declined (Kunzlik, 1988). There is no longer any targeted fishery for basking sharks in Norway, UK or Ireland.

7.1.3 The fishery 2001–2004

Available landings data are presented in Table 7.1. These data were extracted from FishStat Plus database for 1973–2001 and Swedish logbook data. Tables also include landings from Norway (2004) and Portugal (1991–2004). Most catches are from Subareas I, II and IV and are taken by Norway.

No landings were reported by Norway in 2001 and 2002 while some catches were reported in 2003 and 2004. Norway has no longer any direct fishery of basking sharks, and all the reported landings are taken by gill nets as by-catch. For 2001, 2002 and 2003 Portugal reported landings of one ton or less in each year.

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7.2 Biological composition of landings

A series of numbers of basking sharks caught by year was presented in STECF (2003). This series was based on catches from the Achill Island fishery in Ireland and other Irish fisheries. Estimated catch numbers for Norway and UK (Scotland) were based on fin weights raised to total weight and then converted assuming a mean weight of 5 t per shark.

7.3 Fishery-independent information

No information

7.4 Catch per unit of effort

No information

7.5 Discards

No quantitative information exists on basking shark discarding in non-directed fisheries. However, anecdotal information is available that this species is caught in gillnet and trawl fisheries in most parts of the ICES area. Most of this by-catch takes place in the summer months as the species moves inshore. The extent of these catches in unknown, but better information is required.

7.6 Management considerations

At present there are no directed fisheries for this species. The Working Group considers that no fisheries be permitted to target this species unless reliable information exists to estimate sustainable exploitation rates.

The TAC area should correspond to the stock’s distribution, thus the entire ICES area.

Proper quantification of by-catch and discarding of this species in the ICES area is required.

Since 2002, this species has been included in Appendix-II of the CITES convention, meaning that they may only be exported, re-exported or introduced from the high seas if a permit has been issued by the relevant national authorities. Such a permit may only be issued where the management authorities are satisfied that such trade will not be detrimental to the survival of the species in the wild.

In USA waters, the retention of basking shark is prohibited. All individuals captured incidentally must be returned to the sea. Although basking sharks are taken incidentally in Canadian waters, there are no by-catch restrictions there.

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Table 7.1. Landings of basking sharks by ICES Subarea.

1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 I & II 2910 1505 105 1979 1054 137 77 293 135 180 III & IV 257 4 106 135 VIII 1 IX 1 1 1 + X 1 TOTAL 2910 1762 109 1980 1162 137 77 293 1 0 271 180

20000 Basking shark landings XIV 18000 XII 16000 X 14000 IX 12000 VIII 10000 VII VI Tonnes 8000 Vb 6000 Va 4000 III & IV 2000 I & II 0 1973 1978 1983 1988 1993 1998 2003

Figure 7.1. Landings (tonnes) of basking sharks 1973 to 2004. Most recent data may be underestimated. 82 | ICES WGEF Report 2005

4500 Basking shark numbers caught (1946 - 2001) 4000 Norway 3500 Ireland (Achill 3000 Island) UK (Scotland) 2500 Ireland (Other) 2000 Numbers 1500 1000 500 0 1946 1956 1966 1976 1986 1996

Figure 7.2. Estimated numbers caught by Norwegian, Irish and UK (Scottish) fisheries 1947 to 2001. Data from STECF (2003) and values for 1978 are missing.

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8 Demersal elasmobranchs in the Barents Sea

The eight species inhabiting the Barents Sea are starry ray Amblyraja radiata, Arctic skate A. hyperborea, round skate Rajella fyllae, common skate Dipturus batis, spinytail skate Bathyraja spinicauda, sailray D. lintea, long-nose skate D. oxyrhynchus and shagreen ray Leucoraja fullonica (Andriyashev, 1954; Dolgov, 2000; Dolgov et al., 2004b).

Little information is available on the fauna of demersal elasmobranchs in the Barents Sea. Dolgov et al. (2004a) state that 8 species of skates are known to inhabit the Barents Sea and appear regularly and in considerable amounts as by-catch in fisheries. No directed fishery is targeting skates in the Barents Sea. The eight species inhabiting the Barents Sea are: Amblyraja radiata, A. hyperborea, Rajella fyllae, Dipturus batis, Bathyraja spinicauda, D. lintea, D. oxyrhynchus and Leucoraja fullonica (Andriyashev, 1954; Dolgov, 2000a; Dolgov et al., 2004b). Of these, few species occur in greater abundace with the thorny skate as the dominant species, comprising 96% by number of total number and about 92% by weight of skates caught in surveys or as bycatch. The following most abundant species are arctic and round skate, with 3% and 2% by number respectively. The rest of the species are scarce in occurrence (Dolgov et al., 2004b).

8.1 The fishery

8.1.1 Advice and management applicable to 2003 and 2004

ACFM has never provided advice for any of the stocks within this region.

There are no TACs for any of the demersal elasmobranch species in this region.

8.1.2 The fishery in 2004

No Information on the type of fisheries conducted in this area are available to the WG.

Detailed data on catches on skates from the Barents Sea are only available from by-catch records and surveys form 1996–2001 and 1998–2001, respectively, provided by Dolgov et al., 2004a, 2004b. Reported catch data for 2004 originate from Norway and nominate 1 t of skates and rays (“Rajidae”). The summarized catch table can be found at the end of this Report (Figure 8.1 and Table 8.1).

Bottom trawl fisheries mainly targeting cod (Gadus morhua) and haddock (Melanogrammus aeglefinus) as well as longline fisheries for blue catfish (Anarhichas denticulatus), cod and Greenland halibut (Reinhardtius hippoglossoides) conducted through all seasons are generating the by-catch of skates in the Barents Sea. Skate by-catch is generally not used for food and discarded. Dolgov et al. (2004a) estimated the total catch of skates taken by the Russian fishing fleet operating in the Barents Sea and adjacent waters in 1996–2001 ranged from 723–1891 tons, with an average of 1250 tons per year. Thorny skate accounted for 90– 95% of the total skate bycatch.

The names and locations of Russian statistical fisheries areas are shown in Figure 8.2 (Anon. 1957, Dolgov et al., 2004a). Total catch composition based on data derived by observers was calculated for each fishery area and month. The catch statistics on the total for each month from directed fisheries for demersal fish were distributed on local fishery areas. The biomass of bycatch species was calculated for each area and time period based on the assumption that catch biomass of target fishes from catch data in the area proportionally corresponds to the biomass of this species in the catch composition from the observer data in the same area. This method however allows for high uncertainty levels of approximately ±45%. Data obtained by the by-catch assessment reflect distribution and abundance of observed species obtained by surveys in the same area.

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Relative CPUE Data are available for A. radiata, A. hyperborea, R fyllae and D. batis (Figure 8.3) and A. radiata, A. hyperborea and D. batis in trawl and longline fisheries respectively (Figure 8.4). Total catches of skates of Russian fisheries in the Barents Sea and adjacent areas for the years 1996–2001 are given in Table 8.4 and Figure 8.15.

8.2 Fishery-independent information

8.2.1 Groundfish surveys

Data from survey cruises are available from Dolgov et al. (2004b) covering the years from 1998–2001, describing distribution and habitat utilization for six species and abundance and relative biomass estimares of five species of skates in the Barents Sea. Species examined are A. radiata, A. hyperborea, R. fyllae, D. batis, B. spinicauda and D. Lintea.

Abundance and distribution as well as depth of capture are documented for the time of 1998– 2001 in Figures. 8.5–8.8 and Figure 8.9 respectively. Abundance and biomass estimates are given in Table 8.3.

The species composition of skates caught in the Barents Sea differs from those recorded in the Norwegian Deeps and north-eastern Norwegian Sea (Skjaeraasen and Bergstad, 2000, 2001). While thorny skate is the dominant species in both areas, the portion of warm-water species (B. spinicauda, D. Lintea) is lower and the portion of cold-water species (A. hyperborea) is higher in the Barents Sea. Obtained data on stocks of A. radiata and R. fyllae remained almost unchanged during survey timeframe, possibly suggesting stable stocks in the examined area (Dolgov et al., 2004b). The abundance estimate of these authors for A. radiata over the period of 1998–2001 varied from 167 × 106 animals in 1998 to 130 × 106 animals in 1999 and averaged 143 × 106 animals. Estimated biomass varied between 88 000 and 106 000 tons with an average of 95 500 tons. The following most abundant skate species were A. hyperborea and R. fyllae, with an average abundance of 2.6 × 106 animals each, and an average biomass of 3 500 tons and 1400 tons, respectively. The abundance of D. batis and B. spinicauda was lower (0.7 × 106 and 0.5 × 106 animals respectively), though the biomass of D. batis was estimated at 3100 tons due to the large size of the fish, while the biomass of B. spinicauda did not exceed 600 tons. A. radiata were distributed throughout the area of investigation, while the distribution of other species (R. fyllae, D. batis, B. spinicauda, and D. Lintea) was limited to the areas of distribution of Atlantic water, occurring mainly in the southwestern part of the Barents Sea. The preferred depths and temperatures of these species in the Barents Sea correspond well with the data of Skjaeraasen and Bergstad (2001) for the southern distribution area of skates on the slope of the eastern Norwegian Sea. However, it should be noted that the northern border of some species' distributions in the Barents Sea is much further north than previously described in the literature.

8.3 Mean length, weight, maturity and natural mortality-at-age

Length data are available for thorny skate, arctic skate and round skate (Table 8.2), Length- frequency data also from blue and spinytail skates (Figures. 8.10–8.13) from bycatch assessments and survey cruises respectively.

8.4 Spawning and juvenile fishing area closures

Thorny, Arctic and round skates spawn in the Barents Sea (Berestovsky, 1994; Dolgov field observations) whereas the scarcity of small-sized juvenile blue and spinytail skate and sail ray and the absence of mature specimens of these species suggests that their main spawning areas are outside the Barents Sea. Their stocks presumably must be sustained through emigration of animals from areas to the south.

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8.5 Management considerations

The elasmobranch fauna of the Barents Sea is little studied and comprises relatively few species. The most abundant demersal elasmobranch in the area is starry ray, which is widespread and abundant in this and adjacent waters. Further studies to examine the status of some of larger-bodied species (e.g. larger skates, Greenland shark), which may be more vulnerable to over-fishing, may be required

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8.6 Tables and figures Table 8.1: Total Landings of Skates and Rays from ICES Area 27 Subarea I

1973 1974 1975 1976 1977 1978 1979 1980 1981 1982 1983 1984 1985 1986 1987 1988 Belgium . ..1...... France . ..814944...... Germany n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. Iceland ...... Norway . . . 1348222110113147 Portugal . .100111...... Russian Federation . . . . . 1126 168 93 3 1 n.a. 563 619 2137 2364 2051 Spain ...... UK - England & Wales 78 46 49 33 70 9 8 4 . 1 . . . 2 . UK – Scotland . .122...... Total of submitted data 78 46 150 129 125 1183 184 99 5 4 1 573 630 2140 2380 2058

1989 1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 Belgium ...... n.a.n.a.n.a. France ...... n.a..n.a.n.a.n.a.n.a. Germany n.a.n.a....2...... n.a.n.a.n.a. Iceland . . . . 1 . . . 1 . . 4 . n.a. n.a. n.a. Norway 4 1 5 2429729 273 13211230262 1 Portugal ...... n.a.n.a.n.a. Russian Federation 1235 246 n.a. 399 390 369 . . 399 790 568 502 218 173 38 n.a. Spain ...... 7 ...... n.a. n.a. n.a. UK - England & Wales n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. UK – Scotland ...... n.a.n.a.n.a. Total of submitted data 1239 247 5 423 420 443 16 27 403 803 589 518 248 199 40 1

2500

2000 UK – Scot land UK - England & Wales Spain 1500 Russian Federat ion Port ugal Norway Iceland 1000 Germany France Belgium 500

0 1973 1975 1977 1979 1981 1983 1985 1987 1989 1991 1993 1995 1997 1999 2001 2003

Figure 8.1: Total Landings of Skates and Rays from ICES Area 27 Subarea I ICES WGEF Report 2005 | 87

Figure 8.2. Map of Russian statistical fisheries areas in the Barents Sea (from Dolgov et al. 2004a)

Figure 8.3: Distribution of skate by-catch in trawl fisheries (thorny skate A. radiata, round skate R. fyllae, arctic skate A. hyperborea, blue skate D. batis). Circle size represents catch rate in kg per hr. (from Dolgov et al. 2004a) 88 | ICES WGEF Report 2005

Figure 8.4. Distribution of skate by-catch in long-line fishery, kg per 1 000 hooks fisheries (thorny skate A. radiata, arctic skate A. hyperborea, blue skate D. batis). (from Dolgov et al. 2004a)

Figure 8.5. Distribution of A.radiata according to trawl surveys during 1998–2001, specimen per 1 hour trawling. (from Dolgov et al., 2004b)

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Figure 8.6. Distribution of A. hyperborea according to trawl surveys during 1998–2001, specimen per 1 hour trawling. (from Dolgov et al., 2004b)

Figure 8.7. Distribution of R. fyllae according to trawl surveys during 1998–2001, specimen per 1 hour trawling. (from Dolgov et al., 2004b)

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Figure 8.8: Capture sites blue skate D. batis, spinytail skate B. spinicauda and sail ray D. Lintea during 1998–2001. (from Dolgov et al., 2004b)

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Figure 8.9: Bathymetric conditions in the habitat of various skate species in the Barents Sea (thorny skate A. radiata, arctic skate A. hyperborea, round skate R. fyllae, blue skate D. batis, spinytail skate B. spinicauda and sail ray D. Lintea). (from Dolgov et al., 2004b)

Table 8.2: Mean length and sex ratio of some skate species (thorny skate A. radiata, arctic skate A. hyperborea, round skate R. fyllae). (from Dolgov et al., 2004a)

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Figure 8.10. Size distribution of A. radiata during 1998–2001. (from Dolgov et al., 2004b)

Figure 8.11. Size distribution of A. hyperborea during 1998–2001. (from Dolgov et al., 2004b)

Figure 8.12. Size distribution of R. fyllae during 1998–2001. (from Dolgov et al., 2004b)

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Figure 8.13: Size distribution of blue skate D. batis and spinytail skate B. spinicauda during 1998– 2001. (from Dolgov et al., 2004b)

Table 8.3: Estimated abundance (x 106 fish) and biomass (x 103 tons) of five skate species Thorny skate, A. radiata, round skate, R. fyllae, arctic skate, A. hyperborea, blue skate D. batis, spinytail skate, B. spinicauda and sail ray in the Barents Sea during 1998–2001. (from Dolgov et al., 2004b)

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Figure 8.14: Proportion of skates in the total catch of demersal fish by area in the Barents Sea, average for 1996–2001. (from Dolgov et al., 2004b)

Table 8.4: Russian catches of skates in the bottom trawl and longline fisheries by area in the Barents Sea and adjacent waters in 1996–2001 (tonnes, calculated using data on discards). (from Dolgov et al., 2004a)

Figure 8.15. Catch of skates in trawl and long-line fisheries in the Barents Sea in 1996–2001. (from Dolgov et al., 2004b).

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9 Demersal Elasmobranchs in The Norwegian Sea

Little information is available about skate and ray species inhabiting the Norwegian Sea area. Skjaeraasen abd Bergstad (2001) noted several species of skates in the Norwegian Sea and Norwegian Deep. Corresponding to ICES Area II, Amblyraja hyperborea and Bathyraja spinicauda were found in bottom trawls mainly in depths of 800–1400 m and 650–850 m respectively. A. hyperborea were caught in considerable numbers with sizes in length from 14–97 cm and a mean of about 60 cm, whereas B. spinicauda were scarce in distribution. More species found in the area are Amblyraja radiata, Dipturus batis, Dipturus lintea, Dipturus nidarosiensis, Dipturus oxyrinchus, Leucoraja circularis, Leucoraja fullonica, Raja clavata, and Rajella fyllae. A more thorough description of rajiform elasmobranchs from the Norwegian Sea can be found in Stehmann and Bürkel (1984).

It seems noteworthy that the once common Greenland shark Somniosus microcephalus now is depleted in the area and caught only rarely.

9.1 The Fishery

9.1.1 Advice and management applicable to 2003 and 2004

ACFM has never provided advice for any of the stocks within this region.

9.1.2 The fishery in 2004

There is no directed fishery on skates and rays in the Norwegian Sea, though they are caught in mixed fisheries targeting teleost species. Landings data for skates and rays are shown in Table 9.1 and Figure 9.1 for the years 1973–2004. Overall landings throughout time have been low and totaling around 200–300 mt per year for all fishing countries, with moderate fluctuations and one massive temporal peak in the late 1980s where Russian fisheries landed over 1900 mt of skates and rays in 1987, subsequently dropping to low levels two years later again. Russia and Norway are the most prominent and constant countries landing skates and rays from the Norwegian Sea. Landings data for 2004 are not resolved on taxonomic levels and are provided by Norway (135 t) and Germany (7 t).

9.2 Management considerations

There are no TACs for any of the demersal elasmobranch species in this region. The demersal elasmobranch fauna of the Norwegian Sea comprises several species that occur in the Barents Sea and/or the North Sea. Starry ray is one of the more abundant demersal elasmobranchs in the area, and this species is widespread and abundant in this and adjacent waters. Further studies to examine the status of some of larger-bodied species (e.g. larger skates, Greenland shark), which may be more vulnerable to over-fishing, may be required.

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Table 9.1: Total landings (t) of Skates & Rays from ICES Area27 Subdivision Il+lla+llb

1973 1974 1975 1976 1977 1978 1979 1980 1981 1982 1983 1984 1985 1986 1987 1988 Belgium ..1...... Estonia n.a.n.a.n.a.n.a.n.a.n.a.n.a.n.a.n.a.n.a.n.a.n.a.n.a.n.a.n.a.n.a. Faeroe Islands . . . 5 2 1 1 ...... 4 . 15 France . . 1686118211210926 5112142 Germany . 1 52 12 59 114 84 85 53 7 2 112 124 102 95 76 Iceland ...... Netherlands ...... 2...... Norway 201 158 89 34 99 82 126 191 137 110 96 150 104 133 214 112 Portugal . . . 34 39 ...... Russian Federation . . . . . 302 99 39 . . . 537 261 1633 1921 1647 Spain ...... 28.175.9 UK - Eng+Wales+N.Irl. 65 18 14 20 90 10 6 2 . . . 5 1 2 4 . UK – Scotland 21..1...... 21 Total of submitted data 268 178 157 173 351 527 320 318 202 226 128 810 512 1890 2257 1902

1989 1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 Belgium ...... n.a.n.a.n.a. Estonia n.a.n.a.n.a.n.a.n.a.n.a.n.a.n.a.n.a.n.a.n.a.n.a.n.a.5 n.a.n.a. Faeroe Islands . 42 . 2 ...... n.a. . n.a. 2 n.a. France 8561115978685n.a.54727 Germany 3252...... 2.227 Iceland ...... 4.n.a.n.a. Netherlands ...... n.a.n.a.n.a. Norway 148 216 235 135 286 151 239 198 169 214 239 244 233 118 111 135 Portugal . . . . 22 11 . 10 28 46 10 6 3 n.a. 8 n.a. Russian Federation 867 208 . 181 112 257 . . 77 139 247 400 113 38 6 n.a. Spain ...... 3.3156.71132n.a. UK - Eng+Wales+N.Irl. 2 1 . 1 . . 1 4 . . 1 . . n.a. n.a. n.a. UK – Scotland ...... 11133n.a. Total of submitted data 1057 575 246 334 429 426 251 218 285 419 504 658 365 184 166 149

2500

UK – Scot land 2000 UK - Eng+Wales+N.Irl. Spain Russian Federat ion 1500 Port ugal Norway Net herlands 1000 Iceland Germany France Faeroe Islands 500 Estonia Belgium 0

8 73 97 9 976 979 98 991 994 9 000 003 1 1 1 1982 1985 1 1 1 1 2 2

Figure 9.1: Total landings (t) of Skates & Rays from ICES Area 27 Subdivision Il+lla+llb

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10 Demersal elasmobranchs in the North Sea, Skagerrak, Kattegat and Eastern Channel

10.1 Introduction

Although several elasmobranch species occur in the North Sea, Skagerrak/Kattegat and Eastern Channel, the main focus in this chapter will be on skates and rays, in particular on thornback ray Raja clavata. For the fishery this is the most important demersal elasmobranch in the area, and probably most information is available for this species. An assessment of R. clavata was performed as part of the EU funded DELASS project (Heessen, 2003), and will be presented here again.

10.2 Eco-region and stock boundaries

The North Sea is a relatively shallow sea. The northwestern boundary lies along the edge of the continental shelf, west of Orkney and Shetland, whilst the northeastern margin is formed by a trough, the Norwegian Deep, with a depth of up to 450 m. The North Sea is connected to the Baltic by the Skagerrak and Kattegat and has a southerly connection with the Atlantic by way of the English Channel (see also ICES, 2005d (WGRED)).

About 30 species of elasmobranchs may be found in the North Sea (see also REGNS report (ICES, 2005b)). For most species dealt with in this chapter the stock boundaries are not well known. The stocks of Leucoraja naevus, Raja montagui, R. clavata and the lesser spotted dogfish Scyliorhinus canicula probably continue into the waters west of Scotland (and for R. clavata lesser spotted dogfish also into the western Channel). The stock boundary of Dipturus batis is likely to continue to the west of Scotland and into the Norwegian Sea. The stock boundary of Mustelus mustelus and M. asterias is not known.

10.3 The fishery

10.3.1 Description of the fishery

Demersal elasmobranchs are being caught as a by-catch in the mixed demersal fisheries for roundfish and flatfish. For a description of these fisheries see the Report of the North Sea Demersal Working Group (ICES, 2004a). Only a few inshore vessels target skates and rays.

10.3.2 Advice and management applicable to 2003 and 2004

In 1997 ACFM considered the status of the stocks of rays and skates in the North Sea. It was mentioned that the status of the resident stocks varied from almost extirpated (common skate, D. batis) to probably within safe biological limits (starry ray, A. radiata). Stocks of thornback rays (R. clavata) and spotted rays (R. montagui) were considered to be outside safe biological limits and the stock of cuckoo ray (L. naevus) probably only marginally within. ACFM further mentioned that no management objectives were articulated for these stocks, but that their status should be considered since the Common Fishery Policy of the European Union does aim to take into account effects of fishing on species other than those for which annual TACs are set. Also, maintenance of biodiversity is a concern in management of marine fisheries.

In 1999 the EC introduced TAC’s for skates and rays and for spurdog. In 2005 the EC TAC for areas IIa (EC waters) and IV (EC waters) for skates and rays was 3220 t. Norway does not apply separate quota for skates and rays.

In the EC documentation on the TAC for spurdog in 2005 (1136 t for the EC countries) a quota for Norway of 100 t is mentioned. This Norwegian quota is said to include long line catches of tope and of a number of deep water sharks, see Section 2.1 for further details.

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Although there is no EU minimum landing size, commercial fishermen tend to discard individuals < 40 cm length. Within the North Sea area, the Kent and Essex Sea Fisheries Committee, England has a minimum size of 40cm disc width for skates and rays.

In Sweden a number of demersal elasmobranchs are contained in the Swedish Red List: Etmopterus spinax, Greenland shark Somniosus microcephalus, Dipturus batis, and rabbit fish Chimaera monstrosa. Furthermore landings are prohibited of lesser spotted dogfish and R. clavata.

10.4 Biological composition of the catch

10.4.1 Catch data skates and rays

Data on total international landings for North Sea skates and rays are available since 1903 (ICES Fisheries Statistics). Landings data by country for the period 1973–2004 are shown in Table 10.1. Note that for some years not all countries have supplied data. Total international landings of rays and skates, all species combined, were at a level of approximately 13 000 t at the beginning of the 20th century (Figure10.1). They peaked after both World Wars, when fishing had almost ceased for some years, but declined steeply thereafter. The decrease after World War II continued until the mid 1970s, when landings stabilized until the early 1990s. Since then they have decreased to the lowest level observed for 100 years.

In some countries (part of) the landings are reported by species, e.g. Sweden and France. In most countries, however, skates and rays are landed together, most often sorted in particular size categories, rather than by species. They are often gutted, and sometimes only wings are being landed. As part of the EU DELASS project, sampling of the composition of the landings was undertaken in some countries in 2000 and 2001. This sampling is being continued as a result of the EU Data Regulation. Countries sampling the species composition of the landings are Belgium, Netherlands, UK England and UK Scotland (Table 10.6).

Results of sampling in English North Sea ports since mid 2001 show that English ray landings are dominated by R. clavata, other species being mainly R. montagui and R. brachyura. Negligable amounts of L. naevus and A. radiata are also landed. Belgian and Dutch landings of beam trawlers had a similar species composition, but they were dominated by R. montagui (Table 10.6). Whereas some R. brachyura are being landed, the species is only rarely caught during the IBTS in the North Sea. This is possibly because landings are mainly from the flatfish fleet using beam trawls, whereas a light otter trawl is being used during the IBTS. Danish landings from the Norwegian Deeps and the deeper parts of the Skagerrak mainly consisted of R. lintea.

There are no effort data specifically for North Sea rays and skates.

Information on discards in the different demersal fisheries is being collected by several countries but information on discards of rays and skates was not available to the WG.

10.4.2 Catch data demersal sharks

Landings of Lesser Spotted Dogfish, Scyliorhinus canicula are presented in Table 10.7.

10.5 Fishery-independent information

Fishery-independent data are available for the North Sea, Skagerrak and Kattegat from the International Bottom Trawl Survey. In the central and southern North Sea, and in the eastern Channel also different beam trawl surveys are annually conducted which can provide relevant information.

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10.5.1 Skates and rays

For the four most common species in the North Sea, Amblyraja radiata, R. clavata, R. montagui and Leucoraja naevus, Figure 10.18 shows time series of catch rates for the period 1977–2003 based on the quarter 1 IBTS survey. A. radiata is by far the most abundant species, but has limited commercial value and is therefore usually discarded. IBTS catches of A. radiata increased up to the early 1990s and have since decreased slightly. R. clavata catches were more or less stable until the end of the 1980s, but are at a lower level since. No clear pattern can bee seen in the catches of the R. montagui. Catches of L. naevus may have slightly increased between 1977and 1993, but are decreasing since then. Other species of rays are only caught occasionally.

10.5.2 GIS analysis of IBTS data

Terms of Reference for WGEF included the conduct of investigations into the spatial dynamics of shelf-based species, from IBTS and other surveys. In this regard, preliminary distributions and spatial statistics were produced for the following rays species in the North Sea: Ambyraja radiata (starry ray), Raja clavata (thornback ray), R. montagui (spotted ray), Leucoraja clavata (cuckoo ray), R. brachyura (blonde ray) and one shark, Scyliorhinus canicula (lesser spotted dogfish). This analysis, based on fishery independent data provides insight into the spatial dynamics of several elsmobranchs.

Geo-referenced survey number per tow from the IBTS (International Bottom Trawl Survey) employing the GOV trawl for the period 1990 to 2004, comprised the data for the analysis. Number of sets amounted to 14 531 over the period of the survey data used, averaging 380 per survey quarter (quarter 1 and 3, surveyed in all years). Data were available for all quarters of the year for 1991–1997 and the first and third quarter thereafter. The surveyed area encompassed about 700 000 km2 although the entire area was not covered in all quarters.

Within a GIS environment, potential mapping in SPANS was applied to the point estimates of survey number per tow (geo-referenced set) data converting it to a continuous surface comprising different degrees of density of fish (Anon., 2000). Potential mapping transformed geo-referenced number per tow to fish density surfaces by placing a circle around each point and averaging the values of all points that fall within the circle. The circle size selected (28 km diameter) provided complete coverage of the survey area while minimizing gaps in the density surface and thus maximizing spatial resolution. The resulting map was then stratified into 15 classes defining density of the fish, each covering approximately the same amount of area. Each species was assigned its own classification. This classification was then applied to the different periods analysed (refer to Kulka (1998) and Kulka and Pitcher (2001) for a more detailed description of the method).

Initially, each species was mapped by quarters (all years) to determine if there were any seasonal patterns in the distribution. Maps were then produced for three periods: 1990–1995. 1996–2000 and 2001–2004.

In addition to the maps depicting distribution, two spatial measures were calculated: spatial extent (area occupied, in km2) and degree of concentration (in this case expressed as proportion of abundance within 20% of the area of highest concentration). The results of the spatial analysis are summarized in Table 10.5.

S. canicula is distributed mainly on the western side of the North Sea although they are also found in low concentration as far east as the Skagerrak (Figure 10.2). The densest concentrations are located in the Dover Strait to the Wash in the southern extent of the North Sea and in the waters surrounding the Orkney and Shetland Islands to the north. This area corresponds to the warmest bottom waters originating from the west of Britain. The pattern of distribution is similar among quarters (Figure 10.3). The reduced extent of distribution in the

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2nd and 4th quarters is a result of those two periods not being sampled in all years (after 1997). Between 1990 and 2004, the species underwent an increase of about 11% in the extent of distribution and also became more concentrated (Figure 10.4 and 10.5).

Distribution of the four most common skate species is illustrated in Figure 10.6. R clavata may distribute differently among seasons. The concentration of fish observed off the Moray Firth to the Orkney Islands appears to be reduced in the second and third quarters (Figure 10.7) As a whole (all seasons), this species extends over 48% of the North Sea and 71% of the abundance is located near the outer Thames Estuary and the Wash (Figure 10.8).

Similar to R clavata, R.montagui distributes in two concentrations to the north and southwest, mainly to the south (Figure 10.8) covering 29% of the survey area (Figure 10.9). Both the percent of survey area covered and the degree of concentration fluctuated without trend. No distributional shifts were observed between quarters (Figure 10.7).

L. naevus distributed mainly to the north although low concentrations were also observed to the south (Figure 10.6). The largest concentration was centred off the coast between the Firth of Forth and Moray Firth. Significant concentrations were also observed around the Shetland Islands and to the northeast. No seasonal differences were apparent (Figure 10.10). Area occupied (covering 53% of the survey area) and degree of concentration (38%) fluctuated without trend (Figures 10.11 and 10.12).

A. radiata was the most extensively distributed ray species, covering 70% of the surveyed area of the North Sea (Figure10.6). Most of the biomass is concentrated in the Central North Sea. This species appears to be most densely concentrated in the 4th quarter (Figure 10.10) but the degree of concentration was relatively low during most of the year at 45%. No shifts in distribution were apparent among the three periods examined although area occupied and degree of concentration was slightly lower after 1996.

R. brachyura is the least extensively distributed species covering about 5% of the survey area, mainly in the southern North Sea and between the Orkney and Shetland Islands without any apparent shift (Figures 10.6, 10.13). Degree of concentration fluctuated but this may be attributable to the small distribution (Figure 10.14). Small changes could result in large measures of degree of concentration. This species was observed only in the 1st quarter of the year.

This preliminary analysis represents an initial attempt to look at the spatial dynamics of some elasmobranchs in the North Sea. It showed some significant differences not only in the location of the different specie but also changes in area occupied and degree of concentration. None of the species underwent any drastic spatial shifts in the relatively short time frame of the study.

10.5.3 Demersal sharks

IBTS quarter 1 catch trends for the three most abundant demersal sharks, Scyliorhinus canicula, Mustelus mustelus and M. asterias are shown in Figure 10.19. The two species of Mustelus may not always have been identified correctly.

10.6 Mean length, weight, maturity and natural mortality-at-age

No data are presented here, but information on length distributions, individual weights and maturity stages are collected during several surveys and also from landings (an example is shown is Figure 10.15).

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10.7 Recruitment

Information on annual recruitment of might be extracted from an analysis of the length frequency distributions of survey-catches. In general it will be difficult to distinguish a clear recruitment signal, since length distributions of elasmobranchs tend to be very similar from year to year.

The Southern Bight, and especially the Thames Estuary, is an important nursery area for several species, such as R. clavata, Mustelus spp. and Galeorhinus galeus.

10.8 Stock assessment of Raja clavata

An analysis of the quarter 1 IBTS catches of Raja clavata was part of the DELASS-project (Heessen, 2003). The following details are mainly copied from the DELASS-report. Although data for some more years have become available since then, the analysis has not yet been updated.

Conventional tagging data of R. clavata are available and analysed (Walker, 1999). These data indicate that R. clavata have a relatively small range of migration within the North Sea. The first analyses from tagging experiments using data storage tags, however, suggest that R. clavata may migrate over considerable distances (Hunter et al., in press). The assessment presented here presumes that there is a single stock in the southern and central North Sea (IVb and IVc). A further analysis of information from DST tags will be needed to confirm if there are separate stocks in the North Sea and in the Eastern Channel.

10.8.1 Data exploration

10.8.1.1 IBTS data

Data for the North Sea IBTS, 1965–2002, were made available from the ICES IBTS database. As it was not certain whether all catches of rays and skates had been recorded, especially during the earlier years, surveys (a combination of year, quarter, and ship) with no recorded catch of Rajidae were excluded from the analysis. However, even though the Dutch RV ‘Isis’ had twelve surveys without catching rays and skates since 1981, its records were included as all fish species caught were known to have been recorded. All surveys made by RV ‘Thalassa’ were excluded, due to problems with species identification in some years (Y. Vérin, pers. comm.). One haul of 30 minutes by RV ‘Tridens’ in ICES rectangle 35F0 in 1991 with an exceptionally large catch of more than 2500 R. clavata and also R. montagui (confirmed catch) was also excluded. The remaining data were used in the analyses.

The IBTS data include surveys from quarter 1 in the years 1967–1990, surveys in all quarters in the period 1991–1997, and surveys in quarters 1 and 3 for 1998 onwards.

The average catch in number per hour by year and species was calculated from the average catch per ICES rectangle and quarter.

No information on the age composition of North Sea R. clavata is available.

10.8.1.2 Distribution

The distribution of R. clavata in the North Sea is known from recent surveys such as the IBTS (Figure 10.16). R. clavata is presently mainly found in the south-western North Sea. No clear changes in seasonal distribution can be seen, although in quarter 4 some catches have been made in the central-northeastern North Sea. Some of these latter catches still need to be confirmed. They may be based on mis-identification between R. clavata and A. radiata or possibly input errors.

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Some survey data are also available for the early 1900s from the English RV ‘Huxley’ and the Dutch vessel ‘Wodan’ (see also Rijnsdorp et al., 1996). These data allow a comparison of the recent and historic distribution of R. clavata. From the historic survey data it can be seen that, in the first decade of the 20th century, R. clavata was widely distributed over the southern North Sea, with centres of abundance in the southwestern North Sea and in the German Bight, north of Helgoland (Redeke, 1935) (Figure 10.17). The area over which the species is distributed in recent years is much smaller than 100 years ago. The species has disappeared from the southeastern North Sea (German Bight), and catches in the Southern Bight have become limited to the western part only.

10.8.1.3 Trends in abundance and species composition

Trends in abundance, species composition and length frequency are derived directly from the IBTS survey (1965–2001). See also Figure 10.18.

Figure 10.20 shows the relative species composition in the North Sea IBTS averaged over four periods: 1967–1976, 1977–1985, 1986–1992 and 1992–2001. Figure 10.21 also shows the relative species composition but after excluding the most abundant species, A. radiata. A clear gradual shift in species composition can be seen in both figures, confirming the relative increase of A. radiata and the relative decrease of R. clavata, compared to the total catch of rays.

10.8.1.4 Length frequency in surveys

Length frequency distributions for R. clavata caught during the IBTS are shown in Figure 10.22 for 10 cm length classes for four periods. In all periods the length classes 30–39 and 40– 49 cm dominate the catches. No clear change can be seen in the total length range of the catches.

10.8.2 GLM model of survey abundance by length class

Methods

Survey data are the major historical data source for R. clavata in the North Sea. Commercial fisheries data, e.g. CPUE, might be seriously biased as R. clavata is mainly caught as (a negligible) bycatch, and to some extend discarded. In addition, landings of R. clavata are mainly sold and recorded as a mix of ray species, such that landings data are of a limited value. Since 2000 market sampling has been carried out by some countries, and this will supply valuable information about the present species composition. Taking these considerations into account, the analysis of R. clavata in the North Sea was only based on survey data.

Catching R. clavata in the IBTS is a relatively rare event. Of a total of 13 931 hauls, only 605 hauls had a catch of R. clavata (Table 10.8). The high frequency of zero catches in combination with a few, in some cases, high catches was analysed statistically by means of a two-stage model approach. First, the probability of getting a catch with at least one R. clavata was made using a Generalized Linear Model with a binomial distribution and a logit link function. Non-zero catches were afterwards modeled using a Gamma distribution and a log link function. Both models include a season, an area and a period effect: Binomial model: log(p/(1-p)) = area + season + period Gamma model: log(Catch numbers) = area + season + period

where p is the probability of a haul with a catch, and “1-p” is the probability of a haul without a catch of R. clavata. ICES roundfish areas were used for the definition of the area parameter;

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quarter of the year for the season parameter; and the years 1967–1976, 1977–85, 1986–92 and 1993–2002 as the period parameter.

Individual models were fitted for each 10 cm length class of R. clavata and for all length classes combined. The models were implemented using the SAS® GENMOD procedure.

Results

The model parameters area and season are highly significant (Pr <0.0001) for all length groups in the model of the probability of getting a haul with a catch of at least one specimen of R. clavata (Table 10.9). The seasonal effect is highly significant for some length groups. The probability of having a haul with at least one R. clavata is estimated to be 16 times higher for the period 1967–1976 compared to the period 1993–2002. For the individual length classes, this temporal trend is the same for length classes up to 60 cm, while the probability of a catch of fish larger than 60 cm is estimated to have been highest in the period 1977–1992. The probability of a catch is largest in roundfish area 5 (southwestern North Sea) for all length classes.

The results for the model for non-zero catches of R. clavata (Table 10.10) do not show such a consistent pattern as observed for the model of the probability of a catch. For all length classes combined the area and period parameter is highly significant, but for the individual length classes this is only the case for the length classes 30–39 and 40–49 cm, which are most abundant in the catch. For all length classes combined, the average catch in numbers of the non-zero catches in the period 1967–1976 is estimated to be 52% of the catch in numbers in 1993-2002. There is no clear pattern in the period effect on catches by length class, however in general the estimated period factor varies by less than two. Catches are largest in roundfish area 5, but the differences between areas are generally small and, in most cases, not statistically significant.

Bringing the results of the two models together, there has been a steep decline in the number of fishing positions with a catch of R. clavata since 1967. For fishing positions with a catch of R. clavata, the average catch in number seems, however, to have increased slightly. The commercial fishery might simply have fished down the patches with a historically lower density of R. clavata, such that the remaining patches provide relatively larger catches.

The remaining patches might have been less attractive for the commercial fleet, due to factors such as bottom type and low abundance of commercially important fish. The local populations of R. clavata seem to survive there, even though the average fishing pressure for the North Sea is probably too high for a steady population of R. clavata (Walker and Hislop, 1998).

The relatively constant length distributions throughout the whole period support the hypothesis of local patches with a quite stable population. If the stock decline has been caused only by a general recruitment overfishing, it should have been noticeable in the length distributions.

10.8.3 Discussion

Historically, rays and skates have had a low priority in both fisheries management and scientific surveys, and survey catch recording of skates and rays might be missing or done with incorrect species identification. Some quality control of the ICES North Sea survey data has been done previously, but the IBTS database does probably still include mis-recorded species and some catches might be missing as well. No further quality checking was done during for this analysis, and the results should therefore be seen as preliminary.

The GLM model approach seems relevant for the analysis of survey data of rarely caught species with a clustered distribution pattern.

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The North Sea stock of R. clavata has steadily declined since the start of the 20th century. One hundred years ago, the distribution area of the stock included almost the whole North Sea. Today, survey data show a stock concentrated in the waters around the Thames Estuary. The steep decrease in the probability of a catch including R. clavata estimated by statistical models confirms the conclusion of a reduced distribution area. Apparently, there are still patches left in the North Sea with stable local populations. Whether the number of patches will remain high enough to sustain a North Sea population in the long-term is, however, unknown.

The assessment presented here was entirely based on survey data. Similar survey-based assessments would be possible for at least three other ray species occurring in the North Sea: R. montagui, L. naevus and A. radiata.

10.8.4 Conclusions on stock status

WGEF draws the following conclusions on the status of the stocks of demersal elasmobranchs:

Raja clavata – distribution area and abundance have strongly decreased over the past century, and the stock is considered to be depleted.

Raja montagui – abundance seems to be stable, stock status is uncertain.

Amblyraja radiata – increased from the early 1970s to the early 1990s and decreased slightly since. The stock is considered to be in a healthy state.

Leucoraja naevus – abundance is decreasing since the early 1990s, stock status is uncertain.

Dipturus batis – is severely depleted and only seen in small numbers in the northern North Sea.

Scyliorhinus canicula – the distribution area has decreased, but abundance is increasing since the 1970s. The stock is not considered to be threatened.

Mustelus mustelus and M. asterias – abundance of both species is increasing since recent years. The stock status is uncertain.

10.8.5 Management considerations

The TAC that currently is applied to North Sea skates and rays is higher than recent landings. The TAC, however, should only apply to area IIIa, IV and VIId and not to IIa since this is not consistent with the present North Sea eco-region.

Demersal elasmobranchs are being caught in mixed fisheries for demersal teleosts. They are usually landed and reported in mixed categories such as “skates and rays” and “sharks”. For assessment purposes species specific landings data are essential.

The life history parameters for R. clavata are typical for elasmobranchs: slow growth, high age at maturity, and low reproductive capacity. Their distribution area in the North Sea and abundance has severely decreased. The stock of R. clavata may be depleted and requires further management. Measures to afford protection to the largest individuals are required. Since the species is being caught as a by-catch in demersal fisheries, it would profit from a reduction in demersal fishing effort. The most vital part of the (spawning) stock occurs in the southwestern North Sea. Measures to protect R. clavata in this area should be evaluated.

105 | ICES WGEF Report 2005

Tables 10.1 – 10.4. Landings of skates and rays in areas IIIa, IV and VIId by country.

Table 10.1 Total landings (t) of Rajidae in area III (a) 1973 1974 1975 1976 1977 1978 1979 1980 1981 1982 1983 1984 1985 1986 1987 1988 1989 1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 Belgium ...3...... 153.+.1...... Denmark 43353954555864506265333710312666443725292216333027167 1141562236127 Germany++...... +...+++.+...+ Iceland +...... Netherlands . . . 2 143 1 3 2 . . n.a.n.a.n.a.n.a.n.a.n.a.n.a.n.a.n.a.n.a.n.a.n.a.n.a.n.a...... Norway 47 39 45 52 48 50 63 67 79 91 91 100 122 128 127 91 87 65 48 60 80 109 120 149 160 134 208 123 154 163 85 Sweden . . 2 . . . . 1 1 1 2 4 5 5 131313107 283115147 5 1 2 2 12139 UK (E&W_NI_+)1++1....1+...... UK (Scotland).1...... Total of submitted data 91 75 86 112 117 111 128 121 145 157 126 141 230 260 211 151 137 100 84 111 127 157 164 183 181 142 221 166 222 35 208 212

Table 10.2 Total landings (t) of Rajidae in area IV 1973 1974 1975 1976 1977 1978 1979 1980 1981 1982 1983 1984 1985 1986 1987 1988 1989 1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 Belgium 941 659 461 725 769 994 971 751 643 739 1183 1463 1273 708 768 670 459 530 701 716 904 661 577 692 428 373 336 332 370 436 323 276 Denmark 9777554839596122233228271724513124351823193128493320459365343327 Faroe Islands231938146...... 1...... 1...... n.s.n.s. France 231 353 169 171 162 246 179 199 2572 131 220 292 284 202 252 181 110 132 129 110 128 70 76 76 52 47 n.s. 31 61 n.s. n.s. n.s. Germany15924201722942123355763421476103591623112217 Iceland +...... Ireland ....12...... Netherlands 185 283 283 325 287 280 617 305 278 344 408 n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. 675 620 822 n.a. 609 515 693 834 805 686 561 Norway 377 223 454 479 362 304 680 779 551 402 478 512 608 263 417 304 430 347 261 297 408 325 286 180 106 180 152 161 173 113 77 Poland .33...... Sweden . . + ...... ++12+++++++++++++20 UK (E&W_NI_+) 1360 1227 1235 1366 1290 1414 1399 1325 1246 1192 1263 1138 1098 1085 1040 975 974 1037 1149 1446 1440 1546 1336 1020 1009 794 618 516 476 500 537 550 UK (Scotland) 1826 1582 1496 1594 1887 1838 1562 1552 1386 1398 1641 1801 1890 1917 2570 2514 1578 1575 1658 1891 1683 1810 1892 1964 1494 1381 965 860 822 853 741 512 Total of submitted data 5199 4480 4176 4733 4813 5172 5473 4935 6700 4240 5224 5236 5176 4204 5105 4681 3579 3662 3918 4485 4586 5125 4821 4813 3157 3413 2647 2709 2812 2649 2433 2040 Table 10.3 Total landings (t) of Rajidae in area VIId 1973 1974 1975 1976 1977 1978 1979 1980 1981 1982 1983 1984 1985 1986 1987 1988 1989 1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 Belgium 158 113 78 81 81 98 122 63 79 83 114 143 142 111 119 86 89 84 148 121 107 128 155 126 117 66 93 69 79 113 153 96 France . 1359 970 1102 1140 1428 1617 1434 3501 1299 1357 1438 1298 1470 1180 1609 1113 1008 1084 770 726 782 728 891 896 738 ns 693 729 725 796 n.s. Germany...... +...0 Ireland ...... 20 Netherlands...... nananananananananananananana...... Spain ...... 00nananananananana+ UK (E&W_NI_+) . . 123 136 134 115 124 109 131 158 178 217 181 168 252 154 223 167 204 316 273 242 390 354 213 246 437 355 169 140 186 157 UK (Scotland)...... +...... ++..+++...... Total of submitted data 158 1472 1171 1319 1355 1641 1863 1606 3711 1540 1649 1798 1621 1749 1551 1849 1425 1259 1436 1207 1106 1152 1273 1371 1226 1050 530 1117 977 978 1137 253

Table 10.4 Combined landings (t) of Rajidae 1973 1974 1975 1976 1977 1978 1979 1980 1981 1982 1983 1984 1985 1986 1987 1988 1989 1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 Belgium 1099 772 539 806 850 1092 1093 814 722 822 1297 1606 1415 819 887 756 548 614 849 837 1011 789 732 818 545 439 429 401 449 548 476 372 Denmark 140112941029411712572859761641201501177561604745356458764927561341215669154 Faroe Islands231938146...... 1...... 1...... n.s.n.s.... France 231 1712 1139 1273 1302 1674 1796 1633 6073 1430 1577 1730 1582 1672 1432 1790 1223 1140 1213 880 854 852 804 967 948 785 n.s. 724 790 725 796 n.s. Germany159242017229421233557634214761035916231122. . Iceland +...... Ireland ....12...... 20 Netherlands 185 283 283 327 301 283 618 308 280 344 408 n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. 675 620 822 n.a. 609 515 693 834 805 686 561 Norway 424 262 499 531 410 354 743 846 630 493 569 612 730 391 544 395 517 412 309 357 488 434 406 329 266 314 360 284 327 . 276 162 Poland .33...... Spain ...... 00nananananananana+ Sweden . . 2 . . . . 1 1 1 2 4 5 5 131314127 283115147 5 1 2 2 12. 9 20 UK (E&W_NI_+) 1361 1227 1358 1502 1424 1529 1523 1434 1377 1350 1441 1355 1279 1253 1292 1129 1197 1204 1353 1762 1713 1788 1726 1374 1222 1040 1055 871 645 640 723 707 UK (Scotland) 1826 1583 1496 1594 1887 1838 1562 1552 1386 1398 1641 1801 1890 1917 2570 2514 1578 1575 1658 1891 1683 1810 1892 1964 1494 1381 965 860 822 853 741 512 Total of submitted data 5448 6027 5433 6160 6285 6924 7464 6662 10555 5937 6999 7175 7027 6212 6862 6678 5141 5021 5438 5802 5819 6434 6258 6367 4564 4606 3398 3992 4011 3649 3778 2487 ICES WGEF Report 2005 | 106

Table 10.5: Spatial statistics and figure references for species maps. Percent of survey area occupied and degree of concentration refer to the range of values observed in the three periods analysed, 1990–1995, 1996–2000 and 2001–2004. Degree of concentration is measured as the proportion of total abundance in 20% of the area where the species is most highly concentrated.

Degree of Concentration Common % of Survey Area Area Occupied - (% Abun. in 20% Degree of Species Name Map Reference Occupied Trend of area) Concentration - Trend Lesser Scyliorhinus spotted Fig. 10.2, 10.3, 10.4, canicula dogfish 10.5 46-58 Increasing 72-76 Increasing Fig. 10.6, 10.7, 10.8, Raja clavata Thornback ray 10.9 19-48 Decreasing 71-79 Fluctuating Fig. 10.6, 10.7, 10.8, Raja montagui Spotted ray 10.9 19-29 Fluctuating 40-59 Fluctuating

Leucoraja Fig. 10.6, 10.10, naevus Cuckoo ray 10.11, 10.12 36-39 Fluctuating 50-59 Fluctuating

Amblyraja Fig. 10.6, 10.10, Decrease - 1990- Decrease - 1990-95 to radiata Starry ray 10.11, 10.12 70-77 95 to 1996-00 36-45 1996-00

Raja Fig. 10.6, 10.10, brachyura Blonde ray 10.11, 10.12 4-7 Fluctuating 12-74 Fluctuating 107 | ICES WGEF Report 2005

Table 10.6 Species specific landings data.

Species-specific landings (t) of rays and skates: Belgium Area: IV Gear: all gears combined Year L. circularis L. naevus R. brachyura R.clavata R. montagui 2001 0.6 2.7 13.0 199.8 154.1 2002 3.5 5.7 54.9 172.7 198.6 2003 2004

Species-specific landings (t) of rays and skates: France Area: IV Gear: all gears combined Year T. marmorata batis D. oxyrinchus D. L. circularis fullonica L. L. naevus R. clavata R. montagui M. aquila 1999 0.0 1.1 0.0 0.0 0.0 0.0 0.0 0.0 0.0 2000 0.0 2.7 0.8 0.0 0.3 0.3 0.4 0.0 0.0 2001 0.0 3.7 0.0 0.0 0.0 0.2 13.7 2.2 0.0 2002 0.1 0.8 0.6 0.0 0.0 0.3 2.3 0.0 0.1 2003 2004

Species-specific landings (t) for rays and skates, based on market sampling: the Netherlands Area: IV Gear: beam trawl Year A. radiata L. naevus R. brachyura R. clavata R. montagui Total 2000 1.2 3.2 135.9 264.9 287.6 693 2001 1.7 4.0 115.2 314.5 398.5 834 2002not yet available 805 2003not yet available 686 2004 . . 116.0 217.3 228.0 561

108 | ICES WGEF Report 2005

Table 10.6 continued.

Species-specific landings (gutted weight in t) for rays and skates, based on market sampling: UK Scotland Area: IV Gear: all gears Year L. naevus R. montagui D. batis R. alba L. fullonica Total 2000 493.5 29.9 89.7 15.0 119.6 613.2 2001 452.9 29.2 80.0 16.5 113.9 562.1 2002 2003 2004

Species-specific landings (t) for rays and skates: Sweden Area:III, IV Gear: all gear Year Area A. radiata D. batis R. clavata Raja spp. 1996 IIIa 0.04 0.68 6.25 1997 IIIa 0.42 0.04 4.04 1998 IIIa 0.14 0.91 1999 IIIa 0.08 1.76 2000 IIIa 0.17 1.78 2001 IIIa 0.39 11.85 2002 IIIa 0.08 12.88 2003 IIIa 0.65 7.97 2004 IIIa 1996 IV 0.10 1997 IV 0.04 0.08 1999 IV 0.05 0.06 2000 IV 0.09 0.02 2001 IV 0.05 0.05 0.04 2002 IV 0.29 0.05 2003 IV 0.02 0.01 2004 IV

Table 10.7 Landings of lesser spotted dogfish by country.

Lesser Spotted Dogfish (Scyliorhinus canicula ) landings (t) in Areas III and IV 2000 2001 2002 2003 2004 Belgium 74.3 France 0.1 6 8 . UK E&W) NA NA NA 13 . UK Scotlan . . 153 Total 0.1 6 9 13 74.3

Lesser Spotted Dogfish (Scyliorhinus canicula ) landings (t) in Areas VI and VII 1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 Belgium 376.9 France1411781865146266328NA Ireland . . . . . 1487 465 796 886 470 407 518 506 285 124 Spain...... 517322677746502021 UK E&W)...... 11..88 UK Scotlan ...... 37833 Total141171495534875959583521627621401554.9

ICES WGEF Report 2005 | 109

Table 10.8 – Number of survey hauls, and number of hauls with catch of R. clavata by ICES roundfish area and length class, 1965 – 2002 as used in the analysis.

Length Group (cm) Roundfish No. of Area hauls 10-19 20-29 30-39 40-49 50-59 60-69 >=70 All

1 3416 7 15 39 60 7 3 6 101 2 2633 18 34 77 108 32 1 3 156 3 1828 7 15 24 20 7 4 4 56 4 850 3 11 13 19 11 9 22 57 5 518 23 24 62 60 42 42 57 140 6 3524 3 4 17 19 12 4 6 53 7 1162 7 7 15 29 15 0 0 42 All 13931 68 110 247 315 126 63 98 605

110 | ICES WGEF Report 2005

Table 10.9 – Results of the models by length class for the probability of a haul with catch of at least one R. clavata.

Significance test of model parameters (probability of ChiSqure value in a type III test)

Length class (cm) 10-19 20-29 30-39 40-49 50-59 60-69 >=70 all Source Season 0.2608 0.0535 <0.0001 0.0008 0.1333 0.7559 0.0039 0.0003 Area <0.0001 <0.0001 <0.0001 <0.0001 <0.0001 <0.0001 <0.0001 <0.0001 Period <0.0001 <0.0001 <0.0001 <0.0001 <0.0001 <0.0001 <0.0001 <0.0001

Parameter estimates (Estimate), estimate given as factor (Factor) and significance test (Pr>ChiSq) of the parameter estimate against the estimate for the period 1993-2002 10-19 cm 20-29 cm 30-39 cm 40-49 cm Factor Estimate test Factor Estimate test Factor Estimate test Factor Estimate test Period 1967-1976 7,265 1,983 <0.001 11.04 2,401 <0.001 12.74 2,545 <0.001 17.61 2,868 <0.001 1977-1985 3,269 1,184 0.002 5,024 1,614 <0.001 3,680 1,303 <0.001 5,272 1,662 <0.001 1986-1992 1,008 0.008 0.984 1,751 0.560 0.107 1,331 0.286 0.204 1,775 0.574 0.006 1993-2002 1,000 0.000 . 1,000 0.000 . 1,000 0.000 . 1,000 0.000 .

50-59 cm 60-69 cm >=70 cm all Factor Estimate test Factor Estimate test Factor Estimate test Factor Estimate test Period 1967-1976 4,517 1,508 <0.001 1,517 0.417 0.604 0.675 -.394 0.609 16.53 2,805 <0.001 1977-1985 4,817 1,572 <0.001 2,541 0.932 0.045 3,890 1,358 <0.001 5,881 1,772 <0.001 1986-1992 2,044 0.715 0.014 5,058 1,621 <0.001 2,979 1,092 <0.001 2,167 0.773 <0.001 1993-2002 1,000 0.000 . 1,000 0.000 . 1,000 0.000 . 1,000 0.000 .

Parameter estimates (Estimate), estimate given as factor (Factor) and significance test (Pr>ChiSq) of the parameter estimate against the estimate for area 7

10-19 cm 20-29 cm 30-39 cm 40-49 cm

Factor Estimate test Factor Estimate test Factor Estimate test Factor Estimate test Area 1 0.433 -.836 0.121 1,009 0.009 0.985 1,294 0.258 0.409 1,037 0.037 0.876 2 1,186 0.171 0.703 2,320 0.842 0.045 2,530 0.928 0.001 1,849 0.615 0.005 3 0.635 -.455 0.398 1,377 0.320 0.489 1,017 0.017 0.959 0.421 -.865 0.004 4 0.584 -.537 0.438 2,190 0.784 0.109 1,095 0.091 0.819 0.830 -.186 0.550 5 9,364 2,237 <0.001 9,640 2,266 <0.001 14.46 2,671 <0.001 6,839 1,923 <0.001 6 0.083 -2.49 0.002 0.164 -1.81 0.004 0.301 -1.20 0.001 0.168 -1.78 <0.001 7 1,000 0.000 . 1,000 0.000 . 1,000 0.000 . 1,000 0.000 .

50-59 cm 60-69 cm >=70 cm all Factor Estimate test Factor Estimate test Factor Estimate test Factor Estimate test Area 1 0.187 -1.68 <0.001 1,152 0.1410.863 1,425 0.354 0.559 1,147 0.137 0.478 2 1,014 0.014 0.965 0.500 -.692 0.549 0.928 -.075 0.919 1,864 0.623 0.001 3 0.307 -1.18 0.010 2,979 1,092 0.154 1,749 0.559 0.406 0.846 -.167 0.433 4 0.944 -.057 0.889 12.48 2,524 <0.001 20.64 3,027 <0.001 1,976 0.681 0.002 5 7,135 1,965 <0.001 110.6 4,706 <0.001 98.21 4,587 <0.001 15.21 2,722 <0.001 6 0.231 -1.46 <0.001 1,000 <0.001 . 1,000 <0.001 . 0.324 -1.13 <0.001 7 1,0000.000...... 1,0000.000.

ICES WGEF Report 2005 | 111

Table 10.10 – Result of the model by length class for catch numbers for hauls including at least one R. clavata.

Significance test of model parameters (probability of ChiSqure value in a type III test) Length class (cm) 10-19 20-29 30-39 40-49 50-59 60-69 >=70 all Source Season 0.9284 0.8280 0.0267 0.3426 0.0015 0.0038 0.6199 0.0151 Area 0.0605 0.1061 0.0001 0.0020 0.0002 0.0375 0.0010 <0.0001 Period 0.0461 0.0427 <0.0001 <0.0001 0.0179 0.0031 0.1016 <0.0001

Parameter estimates (Estimate), estimate given as factor (Factor) and significance test (Pr>ChiSq) of the parameter estimate against the estimate for the period 1993-2002 10-19 cm 20-29 cm 30-39 cm 40-49 cm Factor Estimate test Factor Estimate test Factor Estimate test Factor Estimate test Period 1967-1976 0.662 -.412 0.237 0.545 -.607 0.034 0.290 -1.24 <0.001 0.397 -.925 <0.001 1977-1985 1,062 0.060 0.846 0.509 -.675 0.012 0.446 -.808 <0.001 0.778 -.251 0.240 1986-1992 1,436 0.362 0.200 0.808 -.213 0.435 0.623 -.474 0.022 0.823 -.195 0.321 1993-2002 1,000 0.000 . 1,000 0.000 . 1,000 0.000 . 1,000 0.000 .

50-59 cm 60-69 cm >=70 cm all Factor Estimate test Factor Estimate test Factor Estimate test Factor Estimate test Period 1967-1976 0.683 -.381 0.219 1,459 0.377 0.647 0.617 -.483 0.576 0.520 -.654 <0.001 1977-1985 1,124 0.117 0.652 1,562 0.446 0.325 1,689 0.524 0.233 0.805 -.217 0.190 1986-1992 1,603 0.472 0.059 3,561 1,270 <0.001 2,390 0.871 0.042 1,080 0.077 0.613 1993-2002 1,000 0.000 . 1,000 0.000 . 1,000 0.000 . 1,000 0.000 .

Parameter estimates (Estimate), estimate given as factor (Factor) and significance test (Pr>ChiSq) of the parameter estimate against the estimate for area 7 10-19 cm 20-29 cm 30-39 cm 40-49 cm Factor Estimate test Factor Estimate test Factor Estimate test Factor Estimate test Area 1 1,726 0.546 0.090 1,529 0.424 0.225 1,365 0.311 0.245 1,186 0.170 0.370 2 1,068 0.066 0.802 1,528 0.424 0.169 1,198 0.181 0.494 1,119 0.112 0.520 3 0.667 -.405 0.194 0.970 -.031 0.924 0.525 -.645 0.033 0.583 -.539 0.028 4 0.539 -.619 0.121 0.941 -.061 0.861 1,617 0.481 0.183 1,545 0.435 0.083 5 1,017 0.017 0.953 0.863 -.147 0.633 0.955 -.046 0.861 1,222 0.200 0.364 6 0.508 -.678 0.198 0.777 -.252 0.589 0.537 -.623 0.056 0.609 -.497 0.052 7 1,000 0.000 . 1,000 0.000 . 1,000 0.000 . 1,000 0.000 .

50-59 cm 60-69 cm >=70 cm all Factor Estimate test Factor Estimate test Factor Estimate test Factor Estimate test Area 1 1,057 0.055 0.879 1,249 0.2220.796 0.339 -1.08 0.098 1,034 0.033 0.862 2 1,159 0.147 0.573 1,209 0.190 0.867 1,479 0.391 0.603 1,288 0.253 0.163 3 0.418 -.872 0.013 1,001 0.001 0.999 0.506 -.681 0.346 0.501 -.692 <0.001 4 0.495 -.704 0.042 1,834 0.606 0.383 1,127 0.119 0.828 0.930 -.072 0.734 5 1,529 0.425 0.103 3,828 1,342 0.032 2,422 0.885 0.085 1,864 0.623 <0.001 6 0.531 -.632 0.040 1,000 0.000 . 1,000 0.000 . 0.477 -.741 <0.001 7 1,000 0.000 ...... 1,000 0.000 .

112 | ICES WGEF Report 2005

total international landings of skates and rays from IV and IIIa 20

10 thousand tonnes 5

0 1900 1910 1920 1930 1940 1950 1960 1970 1980 1990 2000

Figure 10.1 Total international landings of skates and rays from areas IV and IIIa

ICES WGEF Report 2005 | 113

S canicula

Figure 10.2: Distribution of S. canicula, in the North Sea, 1990–2004. Highest concentrations are represented by brown, grey areas are surveyed, with no catches. 114 | ICES WGEF Report 2005

1 2

3 4

Figure 10.3: Distribution of S. canicula in the North Sea, 1990–2004, by quarter. Highest concentrations are represented by brown, greay areas are surveyed, with no catches. (refer to Figure 10.2 for density classification). ICES WGEF Report 2005 | 115

1990- 1995

1996- 2000

2001- 2004

Figure 10.4: Distribution of S. canicula in the North Sea, in three periods. Highest concentrations are represented by brown, grey areas are surveyed, with no catches. (refer to Figure 10.2 for density classification 116 | ICES WGEF Report 2005

90% % of survey area 85% % Abun in 20% of area 80% 75% 70% 65% 60% 55% 50% 45% 40% 1990-95 1996-00 2000-04

Figure 10.5: Area occupied (expressed as a percent of the surveyed area) and proportion of abundance in 20% of the area of distribution where the species is most dense for S. canicula.). ICES WGEF Report 2005 | 117

R L montagui naevus

R A clavata radiata

Figure 10.6: Distribution of R montagui, L. naevus, R. clavata and A. radiata, in the North Sea, 1990-2004. Highest concentrations are represented by brown, grey areas are surveyed, with no catches. 118 | ICES WGEF Report 2005

R montagui 1 2

3 4

R clavata 12

3 4

Figure 10.7: Distribution of R. clavata and R. montagui in the North Sea, by quarter, 1990–2004. Highest concentrations are represented by brown, grey areas are surveyed, with no catches. (refer to Figure 10.6 for density classification. ICES WGEF Report 2005 | 119

R clavata R montagui 1990- 1990- 1995 1995

1996- 1996- 2000 2000

2001- 2001- 2004 2004

Figure 10.8: Distribution of R. clavata and R. montagui in the North Sea, in three periods. Highest concentrations are represented by brown, grey areas are surveyed, with no catches. (refer to Figure 10.6 for density classification. 120 | ICES WGEF Report 2005

90% R. clavata % of survey area 80% % Abun in 20% of area

70%

60%

50%

40%

30%

20%

10% 1990-95 1996-00 2000-04 80% R. montagui % of survey area 70% % Abun in 20% of area

60%

50%

40%

30%

20%

10% 1990-95 1996-00 2000-04

Figure 10.9: Area occupied (expressed as a percent of the surveyed area) and proportion of abundance in 20% of the area of distribution where the species is most dense for R. clavata and R. montagui.).

ICES WGEF Report 2005 | 121

L naevus 1 2

3 4

A radiata 12

3 4

Figure 10.10: Distribution of R. montagui and R. clavata and in the North Sea, by quarter. Highest concentrations are represented by brown, grey areas are surveyed, with no catches. (refer to Figure 10.6 for density classification. 122 | ICES WGEF Report 2005

L naevus A radiata 1990- 1990- 1995 1995

1996- 1996- 2000 2000

2001- 2001- 2004 2004

Figure 10.11: Distribution of Leucoraja naevus and A. radiata and R. montagui in the North Sea, in three periods. Highest concentrations are represented by brown, grey areas are surveyed, with no catches. (refer to Figure 10.6 for density classification. 123 | ICES WGEF Report 2005

70% L. naevus % of survey area % Abun in 20% of area 60%

50%

40%

30%

20%

10% 1990-95 1996-00 2000-04 90% A. radiata % of survey area 80% % Abun in 20% of area

70%

60%

50%

40%

30%

20%

10% 1990-95 1996-00 2000-04

Figure 10.12: Area occupied (expressed as a percent of the surveyed area) and proportion of abundance in 20% of the area of distribution where the species is most dense for L. naevus and A. radiata.). 124 | ICES WGEF Report 2005

1990- 1995

1996- 2000

2001- 2004

Figure 10.13: Distribution of R. brachyurs in the North Sea, 1990–2004. Highest concentrations are represented by brown, grey areas are surveyed, with no catches. ICES WGEF Report 2005 | 125

80% % of survey area 70% % Abun in 20% of area

60%

50%

40%

30%

20%

10%

0% 1990-95 1996-00 2000-04

Figure 10.14: Area occupied (expressed as a percent of the surveyed area) and proportion of abundance in 20% of the area of distribution where the species is most dense for R. brachyura.). 126 | ICES WGEF Report 2005

rays landed by the Dutch fleet in 2004

700000

600000

500000

400000 R. c lav ata R. montagui 300000 R. brachyura

numbers landed 200000

100000

0 30 34 38 42 46 50 54 58 62 66 70 74 78 82 86 90 94 98 102 length (cm)

Figure 10.15 Length composition of the rays landed by the Dutch beam trawl fleet in 2004.

ICES WGEF Report 2005 | 127

Figure 10.16 Distribution of Raja clavata based on catches during the International Bottom Trawl Survey in the period 1977–2005, all quarters combined (ICES-FishMap).

128 | ICES WGEF Report 2005

early 1900s

late 1900s

Figure 10.17 Distribution of Raja clavata in the southern North Sea based on English and Dutch research vessel surveys in the early 1900s and international data from the International Bottom Trawl Survey and the Beam Trawl Survey in the 1990s (see also Rijnsdorp et al., 1996).

ICES WGEF Report 2005 | 129

R. radiata R. montagui

16 0.6 1.2 12 0.4 8 0.2 4

0 0.0 1977 1980 1983 1986 1989 1992 1995 1998 2001 2004 1977 1980 1983 1986 1989 1992 1995 1998 2001 2004

R. clavata R. naevus

4.0 1.2 19.3 3.0 0.8 2.0 0.4 1.0

0.0 0.0 1977 1980 1983 1986 1989 1992 1995 1998 2001 2004 1977 1980 1983 1986 1989 1992 1995 1998 2001 2004

Figure 10.18 Time series of catch rates (number per hour) for the 4 most abundant species of rays in the North Sea. Data from the quarter 1 IBTS survey, roundfish sampling areas 1/7.

Scyliorhinus canicula

2.5

2.0

1.5

1.0

0.5

0.0 1977 1980 1983 1986 1989 1992 1995 1998 2001 2004

Mustelus mustelus

1.2

0.9

0.6

0.3

0.0 1977 1980 1983 1986 1989 1992 1995 1998 2001 2004

Mustelus asterias

1.2

0.9

0.6

0.3

0.0 1977 1980 1983 1986 1989 1992 1995 1998 2001 2004

Figure 10.19 Time series of catch rates (number per hour) for the 3 most abundant demersal shark species in the North Sea. Data from the quarter 1 IBTS survey, roundfish sampling areas 1/7.

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100 90 80 70 60

% 50 40 30 20 10 0 1 1 1 1 9 9 9 9 6 7 8 9 7 7 6 3 - - - - 1 1 1 2 9 9 9 0 7 8 9 0 6 5 2 2

Species R. batis R. brachyura R. circularis R. clavata R. fullonica R. montagui R. naevus R. radiata

Figure 10.20 Relative species composition (numbers) in IBTS survey catches, 1967–2002. All species included.

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100 90 80 70 60

% 50 40 30 20 10 0 1 1 1 1 9 9 9 9 6 7 8 9 7 7 6 3 - - - - 1 1 1 2 9 9 9 0 7 8 9 0 6 5 2 2

Species R. batis R. brachyura R. circularis R. clavata R. fullonica R. montagui R. naevus

Figure 10.21 Relative species composition (numbers) in IBTS survey catches, 1967–2002. Amblyraja radiata excluded.

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1967-1976 1977-1985 0.34 0.36 0.32 0.34 0.30 0.32 0.28 0.30 0.26 0.28 0.24 0.26 0.22 0.24 0.20 0.22

h h 0.20 / 0.18 /

o o 0.18 0.16 n n 0.16 0.14 0.14 0.12 0.12 0.10 0.10 0.08 0.08 0.06 0.06 0.04 0.04 0.02 0.02 0.00 0.00 0 0 0 0 0 0 0 0 0 1 0 0 0 0 0 0 0 0 0 1 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1986-1992 1993-2002 0.13 0.13 0.12 0.12 0.11 0.11 0.10 0.10 0.09 0.09 0.08 0.08

h h

/ 0.07 / 0.07

o o

n 0.06 n 0.06 0.05 0.05 0.04 0.04 0.03 0.03 0.02 0.02 0.01 0.01 0.00 0.00 0 0 0 0 0 0 0 0 0 1 0 0 0 0 0 0 0 0 0 1 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0

Figure 10.22 Length distribution of R. clavata averaged over four periods, 1967–2002. Length is given as lower length of 10 cm length classes.

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11 Demersal Elasmobranchs at Iceland and East Greenland

11.1 The Fishery

From 1973 to 2003, 12 countries, namely Iceland, Norway, Belgium, Faroe Island, Germany, Portugal, Spain and UK – England, Wales, Northern Ireland and Scotland have reported landed skates and rays from Subareas V (Iceland) and XIV (east Greenland). Total landings averaged about 580 t 1973–1990, increased to a peak of 2300 t in 1995 and have averaged about 1800 t since (Table 11.1, Figure 11.1). Ninety-three percent of ray catches came from Subarea V. The share taken by Iceland from this area increased from <50% in the 1970’s to 100% during the last 5 years.

Prior to 1992, all rays, with the exception of Amblyraja radiata and Dipturus batis were reported as Raja rays nei. A. radiata and D. batis made up 47% of the catch since 1992 when it is thought that all species were reported to species. Only minor amounts of Leucoraja fullonica, D. lintea, and Bathyraja spinicauda were reported. The 20 t of spinytail skate reported in 2003 suggest some expansion of effort in deep water in that year.

As a species, D. batis been shown to be vulnerable to exploitation and has been near- extirpated in the Irish and North Seas. Further investigation into D. batis and other rays in Iceland and east Greenland is required, including from fishery independent sources (for example trawl surveys).

Although landings occur in other parts of the range of D. batis in the NE Atlantic range (including Iceland), this is attributed to the redirection of fishing effort from shelf seas and enclosed seas (where heavily depleted populations are now Critically Endangered) into deeper water where previously unfished populations are now being taken.

In addition to skates and rays, Iceland has fished for Greenland shark, averaging 45 t per year between 1989 and 2002 (refer to Table A9, 2003 WGEF Report). Data on catches are not available since 2002.

11.1.1 The fishery in 2004

Data are not yet available for 2004.

11.2 Management Considerations

The elasmobranch fauna off Iceland and Greenland is little studied and comprises relatively few species. The most abundant demersal elasmobranch in the southern parts of the area is starry ray, which is widespread and abundant in this and adjacent waters. Further studies to examine the status of some of larger-bodied species (e.g. larger skates, Greenland shark), which may be more vulnerable to over-fishing, may be required.

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Table 11.1. Reported catches from Iceland (Subarea V) and East Greenland (Subarea XIV)

Spiny Blue (Common) Sail Starry tail skate ray Shagreen ray ray skate Raja rays nei All XIV Va XIVb All Va Va XIVb All Va Va Va (ns) XIVa XIVb All All

1 Iceland Iceland Iceland Iceland Iceland Iceland Iceland Norway Norway Iceland Year3 All All All All All All All All 1973 ------966 4 - - 970 970 1974 ------615 3 - - 618 618 1975 ------560 54 - - 614 614 1976 ------562 1 - 563 563 1977 442 ------593 3 5 1 602 1044 1978 424 ------477 10 - - 487 911 1979 403 ------468 2 - - 470 873 1980 196 ------256 1 - - 257 453 1981 229 ------288 2 - - 290 519 1982 245 ------9 - 283 2 - - 285 539 1983 185 ------12 - 286 4 - - 290 487 1984 178 ------46 - 217 - - 3 220 444 1985 120 ------15 - 164 - - 2 166 301 1986 108 ------44 - 124 1 - - 125 277 1987 130 ------125 - 160 - - - 160 415 1988 152 ------39 - 174 - - - 174 365 1989 152 ------100 - 176 - - - 176 428 1990 222 ------163 - 242 1 - - 243 628 1991 304 ------286 - 316 3 - - 319 909 1992 363 - 363 - - - - 317 - 8 - 1 26 35 1441 1993 206 - 206 - 2 - 2 320 - 6 - 2 10 18 959 1994 243 - 243 - 5 7 12 1242 - 3 - - 9 12 1995 1995 230 - 230 - 24 - 24 1726 - 9 - 9 11 29 2470 1996 183 - 183 - 19 - 19 1498 - 2 - - 10 12 2078 1997 176 - 176 - 16 - 16 1416 - 3 - - 2 5 1964 1998 123 - 123 - 12 - 12 1296 - 9 - - 21 30 1708 1999 112 - 112 - 21 - 21 1132 - 6 - - 10 16 1505 2000 151 3 154 - 27 - 27 1058 - 1 - 7 3 11 1554 2001 121 - 121 - 37 - 37 1200 - 4 1 - 6 11 1611 2002 84 - 84.1 - 32 - 32 1796 - 1 - - 6 7 2087 2003 125 - 125 10 17 - 17 1491 20 1 1 1 15 18 1922 2004 n/a n/a n/a n/a n/a n/a n/a n/a n/a n/a n/a n/a n/a n/a n/a 1Iceland, starry ray - For the years 1977-1992 data are based on published records, could also include R. lintea. 2Since 1993 data are available by gear and by month. ICES WGEF Report 2005 | 135

2500 Starry ray Blue skate Rays NEI 2000 All species + NEI

1500 Catch (t)

1000

500

0 1973 1976 1979 1982 1985 1988 1991 1994 1997 2000 2003

Figure 11.3 Catches of skates and rays in Subarea V and XIV, 1973-2003. Data are not yet available for 2004. 136 | ICES WGEF Report 2005

12 Demersal elasmobranchs at the Faroe Islands

12.1 The fishery

12.1.1 Advice and management applicable to 2003 and 2004

ICES has not previously given advice on the management of demersal elasmobranch fisheries in this area.

The majority of the area is managed by the Faroes through an effort based system which restricts days fishing for demersal Gadoids. Some EU vessels have been able to gain access to the Faroes EEZ where they have been managed under individual quotas for the main target species.

12.1.2 The fishery up to 2004

In recent years, 6 countries, namely the Faroes, Norway, UK (Scotland) UK (England and Wales) France and Germany have reported catches of demersal elasmobranchs from division Vb. Faroese vessels include trawlers and, to a lesser extent, longliners and gillnetters. Norwegian vessels fishing in this area are longliners targeting ling, tusk and cod. UK vessels include a small number of large Scottish trawlers which are occasionally able to obtain quotas to fish in Faroes waters targeting gadoids and deepwater species. French vessels fishing in this area are probably from the same fleet that prosecute the mixed deep-water and shelf fishery west of the UK. In all cases it is likely that demersal elasmobranchs represent a minor bycatch in fisheries targeting other species.

Landings of unidentified rays are presented in table 12.1. French reported landings of D. batis (Table 12.2) since 2000 do not represent the entire catch of this species and an unknown quantity is included in the category of unidentified rays for all counties. Total landings of rays by all countries are combined in Figure 12.1

12.2 Biological composition of the catch

The only catches in this category that have been reported from division Vb are rays and, with the exception of French landings of blue skate Dipturus batis, all rays in this area were reported as Raja rays not elsewhere identieied (NEI). There is no port sampling data available to split these catches by species. It is likely that catches included D. batis, Leucoraja fullonica, Raja clavata and Amblyraja radiata.

There are no reported landings of any demersal shark species in this area.

12.3 Fishery-independent information

No survey data from this area was available to the working group.

12.4 Management considerations

Total international landings of rays appear to have declined in recent years but, without further information on the fisheries, it is impossible to say whether this reflects changes in the status of the stocks or in the pattern of exploitation.

The elasmobranch fauna off the Faeroe Islands is little studied in the scientific literature, though it is likely to be similar to that occurring in the northern North Sea and off Iceland. Further studies to describe the demersal elasmobranch fauna of this region, and to identify what data are available for these species are required. ICES WGEF Report 2005 | 137

Table 12.1a Total landings (t) of Rajidae in Subdivision Vb1 1997 1998 1999 2000 2001 2002 2003 Faeroe Islands 148 121 132 41 18 55 France 3 Germany 1 1 2 Norway 13 22 43 16 15 9 3 Total of submitted data 161 143 176 17 56 27 63

Table 12.1b Total landings (t) of Rajidae in Subdivision Vb2 1997 1998 1999 2000 2001 2002 2003 Faeroe Islands 30 23 43 35 7 43 France 2 Norway 1 23 2 34 6 6 2 Total of submitted data 31 46 45 34 41 13 47

Table 12.1c Total landings (t) of Rajidae in Area Vb (not specified) 1997 1998 1999 2000 2001 2002 2003 6 23 2 2 5 7 6 12 25 12 6 Total of submitted data 11 7 6 35 27 12 8

Table 12.2 Total landings (t) of Blue skate in Subdivision Vb1 France - - - 1 - 2 3 Total of submitted data 0 0 0 1 0 2 3

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400 350 300 250 200 150 100 landings (tonnes) 50 0 1973 1975 1977 1979 1981 1983 1985 1987 1989 1991 1993 1995 1997 1999 2001 2003

international landings

Figure 12.1. Total international landings of rays (all species) from division Vb.

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13 Demersal elasmobranchs in the Celtic Seas (ICES Divisions VI & VII (Except Area VIId))

The demersal elasmobranch fauna of the Celtic Seas is relatively diverse. The main species caught in these areas can be divided into two groups – rays and skates, and demersal sharks.

The dominant skates in the inshore waters of the Celtic Seas are thornback ray Raja clavata and spotted ray Raja montagui. Blonde ray Raja brachyura is also relatively widespread in the area, though it tends to be more abundant in particular areas. Cuckoo ray Leucoraja naevus is more common on the offshore fishing grounds in the Irish Sea (Ellis et al., 2000, 2002) and on the continental shelf of the Celtic Sea (Ellis et al., 2005). Smalleyed ray Raja microocellata is abundant in the Bristol Channel (VIIf), with occasional individuals taken in the Celtic Sea (VIIg), southern Irish Sea (VIIa), and western English Channel (VIIe).

Other rays that are less common, but are recorded in low numbers in fishing surveys include shagreen ray Leucoraja fullonica and undulate ray Raja undulata. Common skate Dipturus batis is known to have declined in the Irish Sea and elsewhere (Brander, 1981; Rogers and Ellis, 2000) and is only recorded very occasionally in the inshore waters of the area, though they are still encountered in the Celtic Sea and along the edge of the continental shelf. Undulate ray Raja undulata is found in very localised populations on the west coast of Ireland, with occasional records in the English Channel. There are few contemporary records of white skate Rostroraja alba and sandy ray Leucoraja circularis.

Other batoids in the area include stingray Dasyatis pastinaca, marbled electric ray Torpedo marmorata and electric ray T. nobiliana, though these species may be regarded as vagrants from more southern waters, and these species are generally discarded if caught.

In inshore waters, rays and skates in the Celtic Seas are usually caught as by-catch in mixed demersal fisheries, which are either directed at flatfish (plaice and sole), particularly in the Irish Sea, or at roundfish (cod, haddock, whiting) elsewhere. The main countries involved in this fishery are Ireland and the UK, with significant landings by France and Spain, and smaller catches by Belgium and Germany. The main gears used are otter trawls and bottom-set gillnets. The Belgian fishery is carried out by a beam-trawl fleet.

There are Nephrops fisheries in the Irish Sea, Celtic Sea VIIg, the Porcupine Seabight (VIIj) and at the Aran Islands, (VIIb). All of these catch various ray species as bycatch.

In the deepwaters of Area VI and VII there is a ray bycatch in fisheries for monkfish, megrim, hake and orange roughy. These species include Leucoraja fullonica, L. circularis and Dipturus spp.

The dominant demersal shark species in inshore waters is lesser-spotted dogfish Scyliorhinus canicula (Ellis et al., 2005). Greater-spotted dogfish Scyliorhinus stellaris is also widespread in the area, though occurs typically on rocky inshore grounds that are not sampled effectively in many fishing surveys. This species is comparatively abundant around parts of the Welsh coastline (Ellis et al., 2005).

Smoothhounds, Mustelus spp. and tope Galeorhinus galeus are relatively common, with juveniles often reported from the inshore waters of the Bristol Channel and Cardigan Bay (Ellis et al., 2005). Further offshore, black-mouth dogfish Galeus melastomus are occasionally recorded in the Irish and Celtic Seas, though are most abundant along the edge of the continental shelf and in deeper waters. Angel shark Squatina squatina is now reported only infrequently in the area, though it was previously more common (Rogers and Ellis, 2000). 140 | ICES WGEF Report 2005

Several species of elasmobranch may form locally abundant populations, examples including R. undulata in Tralee Bay, R. microocellata in the Bristol Channel, S. stellaris around the Lleyn Peninsula, and formerly S. squatina in Cardigan Bay, Start Bay and Clew Bay.

A recent analysis of discard patterns (Borges, 2005) shows that there is a nursery area for dogfish (Scyliorhinus spp.) in the Celtic Sea (Area VIIg) and another at the Porcupine Bank (Area VIIjk).

13.1 The fishery

13.1.1 Advice and management applicable to 2003 and 2004

ACFM has never provided advice for any of the stocks within this region.

13.1.2 The fishery in 2004

13.1.2.1 Rays and skates

Most skate species are taken as a by-catch in trawl fisheries, though there are some localised fisheries that target thornback rays using long line and tangle nets. There is a small fishery in south-east Ireland targeting ray in the southern Irish Sea (Area VIIa), using rockhopper otter trawls.

Landings tables for Rajidae by country are provided in Tables 13.1a–e. Landings for the entire data series available are shown in Figure 13.1. Where species specific landings have been provided they have been included in the total for the relevant year.

Landings appear as a series off peaks and troughs, with lows of approximately 14 000t in the mid 1970s and 1990s, and highs of just over 20 000t in the early and late 1980s and late 1990s. There has been a general decline in landings over the past five years. While there have been fifteen countries involved in the fishery, only six of these - Belgium, France, Ireland, UK-England & Wales, Scotland and Spain, have continuously landed large amounts of these species.

13.1.2.2 Demersal sharks

Scyliorhinus canicula is not targeted in commercial fisheries, and discards are known to have a high survivorship (Revill et al., 2005). A largely unknown number are kept for use as bait in the Irish Sea and Bristol Channel whelk Buccinum undatum fishery, and the northwest Ireland crab fishery, but these may not routinely be declared in the landings.

There is a targeted spurdog fishery, as discussed in Chapter 2. There is no directed fishery for other demersal sharks. Tope, smoothounds and catsharks of a marketable size are sometimes retained if caught. There is also a large recreational fishery for most of the demersal sharks, particularly those close to shore, with some ports having locally important charter boat fisheries.

Species-specific landings for some demersal shark species are provided in Tables 13.5 – 13.7.

Landings tables for Scyliorhinus canicula have not been provided as it was not possible to disaggregate this species from the many categories under which it is declared and the lack of consistency by which it is categorised. In the absence of accurate species-specific information, it is recommended that in the future, one category be used to report this species (See Section 1.10).

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13.2 Biological composition of the catch

13.2.1 Rays and skates

Rays are usually landed as a mixture of several species, and only as part of the DELASS project has some information on species composition become available for the first time from different countries (Heessen, 2003). Some countries have continued to provide landings by species but most are supplied as mixed species information. Species breakdown per country (where available) is supplied in Table 13.2–13.4

13.2.1.1 Discard information – rays and skates

Species information on the numbers of rays and skates caught by the Irish discard observer programme is presented in Table 13.8 Without comparable landings data, however, it cannot be used to split national landings data. Likewise, because of the small number of data points in certain years, this information can not be used to show trends in ray species discards.

Table 13.9 shows the raised weights of different species of Rajidae from the Scottish discard programme. It should be noted that these data are based on a small sample size and raising factors used are very large; the figures presented here should therefore be considered as indicative rather than accurate estimates

Skates and rays are generally discarded at lengths of <40cm. Figure 13.2 shows the discard and retention rates of some common species.

13.2.2 Demersal sharks

13.2.2.1 Discard information – demersal sharks

Some information on discards of small demersal sharks species was provided to the group. Smoothhounds and lesser-spotted dogfish are generally discarded, though specimens >50 cm length are sometimes retained in some fisheries.

Discard length rates are presented for lesser-spotted dogfish in Figure 13.3

Figure 13.4 shows the prevalence of juvenile Scyliorhinus spp. in Areas VIIg in comparison to the other areas in this region.

13.3 Quality of catch and biological data

Tables with landings data were prepared using the ICES Statlant database and data provided by working group members. The Statlant database holds data for the years 1973–2003. France and Belgium have provided relevant species specific landings for the Celtic Seas. Where this is not specified, the data are for all species combined is given.

Landings estimates for 2003 and 2004 were provided by Ireland, Spain (Basque Country), U.K.(Scotland) and Belgium. Landings data were not provided by France. The landings tables provided are different to those supplied in previous years. Area VI has been split into VIa and VIb as it is considered that they are different habitats with little migration between populations. Area VIIb has been combined with Area VIIk as they are considered to be one deepwater area. These figures have been combined with those from Areas VIIb and VIIj to provide landings for one western area. Likewise, figures from Areas VIIe,f,g and h have been combined as a southern waters grouping. It proved impossible to disaggregate the data for Areas VIIb and c. Data for Division VIId has been included in the North Sea Ecoregion (Section 10).

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13.3.1 Effort data

Most elasmobranchs in this eco-region are caught as a bycatch of Demersal fisheries directed at teleosts. Effort data for these fisheries are compiled by different assessment working group such as the Northern and Southern Shelf Working Groups (NSWG and SSWG). WGEF, therefore, did not attempt to present relevant effort data in this report.

13.4 Fishery-independent information

13.4.1 Groundfish surveys

There are several potential sources of fishery- independent survey data for demersal elasmobranchs in this Area. GOV trawl surveys are undertaken off North-west Scotland and western Ireland, on the Porcupine Bank, and in the Irish and Celtic Seas during the internationally-coordinated IBTS surveys for southern and western waters (Marine Institute, FRS, CEFAS, IFREMER and IEO). There are also several national surveys, for example the 4m-beam trawl surveys of the inshore grounds of the western English Channel, Bristol Channel and Irish Sea (CEFAS), and rockhopper surveys in the Irish Sea (DARD). These surveys are summarised in Table 13.4.1

Table 13.4.1 Surveys by country and gear type in the Celtic Seas Region

Ireland UK (E+W) UK (Scot) France Northern Ireland ICES Division GOV BeamPHHT* GOV GOV GOV GOV VIa X X VIb X VIIa X X X X X VIIbcjk X X X X VIIefgh X X X X X

GOV: Grand Overture Verticale; Beam: 4m beam trawl; PHHT: Portuguese High Headline Trawl.

* Since 2004, the UK (E&W) Q1 survey in the Celtic Sea is to collect biological data, and is not totally standardised with previous years

Exploratory analyses of elasmobranchs in selected surveys have been undertaken to examine the utility of these surveys. Data from the Irish Groundfish survey (IGFS) is presented in Table 13.10. These show the numbers in the catch of different ray species by ICES Area. The demersal elasmobranchs captured in CEFAS 4m-beam trawl and Portuguese High Headline Trawl (PHHT) surveys in western areas were recently analysed in terms of size distribution, species composition and trends in relaative abundance (Ellis et al., in press). It must be recognised, however, that these surveys were designed to sample commercial teleosts, and so are not ideal for elasmobranchs, and survey catch rates are generally variable. It is recommended that future studies examine data from all appropriate surveys for trends in elasmobranch catches.

Skates (Rajidae): Several species of skate are recorded in surveys, with survey catches on the shelf dominated by thornback, spotted, cuckoo, blonde and small-eyed ray. These species are recorded regularly and often in comparatively large numbers, in both trawl surveys and beam trawl surveys. Trawl surveys on offshore grounds, such as the Rockall Deepwater survey, carried out by Scotland every two years, sample mostly larger individuals. This is mainly because of gear effects caused by the different nets types used during these surveys. The Irish Sea Beam trawl surveys sample younger age classes well, although larger individuals (>70 cm) are only caught occasionally, which may be a gear effect. Catch rates for annual surveys

ICES WGEF Report 2005 | 143

tend to be quite variable, with many zero catches. Analyses of more specific areas within the survey areas may be more appropriate for some species.

Contemporary surveys do record other skate species, including shagreen ray, common skate and undulate ray, though catch rates of these species are highly variable. The absence of white skate and low incidences of sandy ray in contemporary trawl surveys is cause for concern. It is unclear as to whether surveys are not sampling appropriate areas, or that these species have declined in the area.

Tope and smooth-hounds (Triakidae): Groundfish surveys are not useful for estimating tope abundance. For smoothounds however these surveys may be able to provide better data for juveniles.

Catsharks (Scyliorhinidae): Groundfish surveys are useful for providing proportions of adults and adult juveniles within a population. For greater-spotted dogfish groundfish surveys can be used in the absence of any other data.

Other species: The occurrence of other demersal elasmobranchs in trawl and beam trawl surveys are sporadic.

13.5 Mean length, weight, maturity and natural mortality-at-age

Some length-weight information should be available from various groundfish surveys. It is recommended that these data be examined for the next meeting of this working group.

13.6 Recruitment

Juveniles of most species are found in most Groundfish surveys and in discards, although usually in small numbers. In future it may be possible to examine these data for recruitment. However for areas where elasmobranch catches are low, such as rajidae in Area VIIj, it will not be possible to estimate recruitment without dedicated surveys.

13.7 Stock assessment

No assessment could be carried out for any of the stocks in this eco-region.

13.8 Stock and catch projection

No assessment could be carried out for any of the stocks in this eco-region.

13.9 Reference points

No reference points have been proposed for these stocks.

13.10 Quality of the Assessment

No assessment could be carried out for any of the stocks in this eco-region.

13.11 Spawning and Juvenile fishing area closures

Tralee Bay (Area VIIj) is voluntarily closed to commercial fishing to protect regionally important elasmobranchs such as Raja undulata and Squatina squatina, which are only found in localised populations on the Irish West coast.

There are no other known specific closed areas for the protection of elasmobranchs.

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13.12 Management considerations

Under current EU legislation, where a directed fishery for skates takes place, a mesh size in the cod-end of no less than 280 mm is required.

Within UK waters, the South Wales Sea Fisheries Committees has a bylaw stipulating a minimum landing size for skates and rays.

Preliminary analyses of survey show that catch rates of elasmobranchs are variable, therefore precluding an accurate estimation in trends in abundance. Although the relative abundance of Raja clavata seems stable at the present time, this species is known to have been more abundant in the past. More accurate assessments of the status of this species are required. Leucoraja naevus is an important commercial species in the Celtic Sea, where it is taken in French trawl fisheries. Preliminary assessments were made during the DELASS project, and further assessments are required. The relative abundance of lesser-spotted dogfish and Raja montagui in this eco-region appear stable, and assessments for these species may be of a lower priority.

There are several species of demersal elasmobranch that, although occurring sporadically throughout much of the Celtic Seas region, have certain areas where they are locally abundant. Localised depletion of the species at these sites could therefore have a major impact on the population as a whole. For example, there are anecdotal and historical reports suggesting that localised populations of Rostroraja alba were targeted in fisheries in the Baie de Douarnanez (Brittany) and off the Isle of Man (ICES, 2002a), and this species is now rarely observed in the region. Similarly the localised populations of Squatina squatina in Start Bay (VIIe) and Cardigan Bay (VIIa) have declined severely. Hence, the status of species that are considered “Locally important” may also need to be monitored and assessed at a more local scale. Examples of this include: Raja undulata in Tralee Bay (VIIj) Raja microocellata in the Bristol Channel (VIIf) Scyliorhinus stellaris around Anglesey and the Lleyn Peninsula (VIIa) Squatina squatina in Clew Bay (VIIb)

There is a TAC for spurdog in this eco-region. This is dealt with in Chapter 2.

Norway has a quota of 100 t for spurdogs. This Norwegian quota is said to include long line catches of tope and of a number of deep water sharks.

There are no TACs for any of the other relevant species in this region.

It has been difficult for WGEF to deal with elasmobranchs in this region adequately. This is because the main fishing nation, France does not participate in the group and supplies iccomplete data.

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Table 13.1a Total landings (t) of Rajidae in Area Vla 1998 1999 2000 2001 2002 2003 2004 Belgium 2 4 2 4 2 8 9 Denmark + + . . . . . Faeroe Islands ...... France 333 0 321 278 212 183 na Germany 16 7 1 1 3 22 Ireland 488 388 274 238 311 364 363 Netherlands ...... Norway 50 29 49 20 25 2 2 Poland ...... Spain 69 34 2 + 9 27 14 UK - Eng+Wales+N.Irl. 157 67 108 65 114 159 66 UK – Scotland 1460 1324 1316 1263 1136 1307 1012 Total of submitted data 2575 1853 2073 1869 1809 2053 1488

Table 13.1b Total landings (t) of Rajidae in Area Vlb 1998 1999 2000 2001 2002 2003 2004 Estonia . . . 56 1 . . Faeroe Islands . . . . na France 0 0 7 5 5 2 0 Germany 36 67 76 8 1 6 na Ireland 15 28 20 10 1 18 na Norway 98 59 120 80 44 61 na Portugal 26 24 29 17 31 18 na Russian Federation . . 5 8 . . na Spain 483 322 347 158 36 46 na UK - Eng+Wales+N.Irl. 134 147 156 120 92 47 47.8 UK – Scotland 101 123 204 97 79 146 na Total of submitted data 893 770 964 559 290 344 47.8

Table 13.1c Total landings (t) of Rajidae in Area VlIa 1998 1999 2000 2001 2002 2003 2004 Belgium 398 542 504 724 997 830 860 France 285 n.s. 163 343 349 322 na Ireland 692 827 759 807 1032 1086 825 Netherlands 4 4 6 + + + + Norway ...... UK (E&W_NI_+) 1009 936 671 983 863 1184 533 UK (Scotland) 52 33 86 80 68 67 38 Total of submitted data 2440 2342 2189 2937 3309 3489 2256

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Table 13.1d Total landings (t) of Rajidae in Area VIIbcjk 1998 1999 2000 2001 2002 2003 2004 Belgium . 24 5 . 5 1 na France 500 ns 568 362 272 192 na Germany 17 10 21 7 + 3 15 Ireland 741 740 653 383 354 435 511 Spain (b) 1978 2419 2573 1205 2939 1281 7 UK (E&W_NI_+) 376 352 597 545 373 350 364 UK (Scotland) 67 121 189 162 124 226 70 Total of submitted data 3679 3642 4601 2664 4062 2487 968

Table 13.1e Total landings (t) of Rajidae in Area VIIefgh 1998 1999 2000 2001 2002 2003 2004 Belgium 381 343 313 339 464 710 617 Denmark . . . . . France 6578 6551 6248 6245 5799 6124 . Germany . . . . + . 3 Ireland 447 408 203 481 730 839 859 Netherlands 9 na 7 7 11 . Norway . . . 11 . . . Poland ...... Spain (b) 1190 2648 1706 1145 653 31 15 UK (E&W_NI) 1791 1356 1545 1571 1695 1570 1420 UK (Scotland) 2 2 149 Total of submitted data 10395 11308 10022 9801 9352 9274 3063

Table 13.1f Total Landings of Rajidae in the Celtic Seas 1998 1999 2000 2001 2002 2003 2004 Belgium 781 913 824 1067 1467 1549 1485 Denmark ...... Estonia . . . 56 1 . . Faeroe Islands ...... France 7696 6551 7307 7233 6637 6823 ns Germany 69 84 98 16 2 12 40 Ireland 2382 2390 1909 1919 2428 2742 2559 Netherlands 13 4 13 7 11 na na Norway 148 88 169 111 69 63 2 Poland ...... Portugal 26 24 29 17 31 18 . Russian Federation . . 5 8 . . . Spain 3720 5423 4628 2508 3637 1385 36 UK - Eng+Wales+N.Irl. 3467 2858 3077 3283 3137 3310 2431 UK – Scotland 1680 1603 1795 1604 1407 1746 1270 Total of submitted data 19981 19938 19854 17830 18828 17648 7823

ICES WGEF Report 2005 | 147

UK – Scotland 25000 UK - Eng+Wales+N.Irl. Spain 20000 Russian Federation Portugal Poland 15000 Norway Netherlands 10000 Ireland Germany 5000 France Faeroe Islands Estonia 0

1973 1976 1979 1982 1985 1988 1991 1994 1997 2000 2003 Denmark Belgium

Figure 13.1 Total Landings of Rajida in the Celtic Seas. 148 | ICES WGEF Report 2005

Table 13.2a Species-Specific French Landings, all areas combined

Species 1995 1996 1997 1998 1999 2000 2001 T. marmorata 15 16 27 33 24 7 1 D. batis 296 331 344 278 130 468 537 D. oxyrhinchus 366 330 315 356 20 96 47 L. circularis 529 519 537 454 82 327 275 L. fullonica 56 50 43 40 21 21 36 L. naevus 3741 4043 4722 3848 1021 2541 2236 R. clavata 1739 1652 1535 931 478 865 618 R. montagui 882 973 1176 981 551 1062 1071 R. undulata 12 6 10 2 1 0 0 D. pastinaca 1 1 4 2 10 3 M. aquila 3 2 2 1 2 1 0 Various 2066 2507 2830 1111 6657 3558 2680 Total 9706 10430 11544 8035 8989 8956 7504

Table 13.2b French Species Specific Landings by Area

Year 1999 2000 2001 2002 1999 2000 2001 2002 Area VI VI VI VI VII VII VII VII T. marmorata 0.0 0.0 0.0 0.0 0.1 0.1 0.0 0.2 D. batis 8.8 73.3 69.9 5.0 118.3 384.6 471.0 263.2 D. oxyrinchus 5.4 39.6 18.3 42.8 15.7 53.4 30.9 73.7 L. circularis 0.3 8.5 7.2 2.4 66.2 264.0 236.4 157.3 L. fullonica 0.0 0.4 0.1 0.3 22.5 45.0 47.3 65.1 L. naevus 5.6 57.0 61.1 43.3 706.8 1728.4 1660.2 1159.1 R. clavata 10.9 60.8 50.4 49.8 450.2 710.8 548.5 506.1 R. microocellata 0.0 0.0 0.0 0.0 7.5 0.5 0.9 0.0 R. montagui 0.1 0.5 0.7 0.8 533.9 1004.7 1065.8 886.2 R. undulata 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 Large rays 0.0 3.5 0.0 0.0 12.0 29.9 12.1 1.5 miscellaneous (D. batis, R. alba, R. oxyrinchus, D. nidarosiensis) D. pastinaca 0.0 0.0 0.0 0.0 2.0 8.6 2.8 4.8 M. aquila 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.1 Total 31.1 243.6 207.6 144.5 1935.2 4229.9 4076.0 3117.3

Table 13.3 Spain (Basque) species specific landings, Areas VI, VII and VIII

Year 2000 2001 2002 2003 L. naevus 330.3 290.9 290.0 287.0 R. asterias 0.0 0.1 0.0 0.0 R. batis 8.3 9.6 0.0 0.0 R. clavata 51.7 107.9 65.1 47.1 R. fullonica 5.3 33.5 0.0 1.5 R. montagui 2.7 6.2 20.9 5.1 R. oxyrhinchus 0.0 0.2 0.0 0.0 R. undulata 0.5 0.0 0.0 0.1 Total 398.8 448.4 376.0 340.9

No data available for 2004

ICES WGEF Report 2005 | 149

Table 13.4 Belgian Species-Specific Landings by area

2001 2002 2001 2002 2001 2002 Area VIIa VIIa VIId VIId VIIf,g VIIf,g L. circularis* 9.3 22.7 6.0 3.2 104.7 86.5 L. naevus 77.6 137.3 0.0 0.2 27.9 44.3 R. brachyura 137.8 228.0 9.8 11.3 27.4 80.0 R.clavata 382.8 449.7 58.5 68.9 116.1 108.2 R. montagui 99.6 158.9 15.8 31.5 65.1 133.7 Total 707.0 996.6 90.1 115.2 341.2 452.8

* These records are considered by WGEF to be misidentified R. microocellata.

Table 13.5a - Smooth hound (Mustelus mustelus) landings - ICES Area VI & VII

1997 1998 1999 2000 2001 2002 2003 2004 Ireland ...... 1 UK (E&W) . . . 12 74 54 67 56 Total . . . 12 74 54 67 57

Table 13.6 - Smooth hounds nei (Mustelus spp.)landings - ICES Area VI & VII

1997 1998 1999 2000 2001 2002 2003 2004 Belgium ...... 8 France 511 590 + 814 989 1205 775 n.a. Ireland + + + + + + 2 2 Spain 5 7 4 6 20 24 36 17 (Basque country) Total 516 597 4 820 1009 1229 813 27

Table 13.7 - Tope shark (Galeorhinus galeus) landings - ICES Area VI & VII

1997 1998 1999 2000 2001 2002 2003 2004 France 409 312 + 368394 324 284n.a. Ireland . . . . 4 1 64 Spain . . . . + 242 3n.a. Spain (Basque country) . . . . + + 3 15 UK (E&W_NI_+) 33 42 61 97 71 60 55 64 Total 442 354 61 465 469 627 34883 * In years with landings on Spain and Spain (Basque country) the total annual landings value do not take into account Basque country landings.

150 | ICES WGEF Report 2005

Table 13.8 Ray species (numbers) discarded. These are not raised to fleet. (Source: Irish discard monitoring programme, 1993–2004).

ICES DIVISION Species VIa VIb VIIa VIIb VIIc VIIg VIIj Total Amblyraja hyperborea 8 8 Raja brachyura 124 3 3 1 28 159 Neoraja caerulea 2 2 Leucoraja naevus 719 1 5 1 18 17 761 Raja spp. 838 59 3072 665 2 384 252 5272 Leucoraja circularis 4 10 14 Leucoraja fullonica 1 1 Dipturus batis 104 128 4 19 255 Raja montagui 776 7 1 87 1 872 Raja clavata 421 6 16 6 27 476 Total 2995 60 3093 814 14 500 344 7820

Table 13.9. Weights of rays and skates discarded (t) by the Scottish Fleet to the west of Scotland, 1999–2000. (Source: UK (Scotland) Discard Observer Programme)

Area VIa

1999 2000

L. naevus 205.8 194.1

D. batis 269.1 13.2

R. montagui 98.3 67.4

L. fullonica 03.1

A. radiata 00

R. clavata 14.3 16.9

L. fullonica 0.2 0

Total 587.7 294.7

ICES WGEF Report 2005 | 151

Raja Clavata

16 0

14 0

12 0

10 0

Discarded Ret ained

Figure 13.2a Length distribution of Raja clavata discarded and retained in fisheries in western waters. These data are aggregated across individual catch samples for all gears and divisions combined. (Source: UK (E&W) Discard Surveys).

Raja montagui

18 0

16 0

14 0

12 0

10 0

Discarded Retained

Figure 13.2b. Length distribution of Raja montagui discarded and retained in fisheries in western waters. These data are aggregated across individual catch samples for all gears and divisions combined. (Source: UK (E&W) Discard Surveys).

152 | ICES WGEF Report 2005

Leucoraja naevus

500

450

400

350

300

250

200

150

100

0 12 14 16 18 20 22 24 26 28 30 32 34 36 38 40 42 44 46 48 50 52 54 56 58 60 62 64 66 68 70 72 74 76

Discarded Retained

Figure 13.2c. Length distribution of Leucoraja naevus discarded and retained in fisheries in western waters. These data are aggregated across individual catch samples for all gears and divisions combined. (Source: UK (E&W) Discard Surveys).

Raja microocellata

140

120

100

0 11 14 17 20 23 26 29 32 35 38 41 44 47 50 53 56 59 62 65 68 71 74 77 80 83 86 89 92 95

Discarded Retained

Figure 13.2d. Length distribution of Raja microcellata discarded and retained in fisheries in western waters. These data are aggregated across individual catch samples for all gears and divisions combined. (Source: UK (E&W) Discard Surveys). ICES WGEF Report 2005 | 153

Lesser-spotted dogfish

4500

4000

3500

3000

2500

2000

1500

1000

500

0 10 13 16 19 22 25 28 31 34 37 40 43 46 49 52 55 58 61 64 67 70 73 76 79 82 85

Discarded Retained

Figure 13.4 Length distribution of lesser-spotted dogfish discarded and retained in fisheries in western waters. These data are aggregated across individual catch samples for all gears and divisions combined. (Source: UK (E&W) Discard Surveys).

Dogfish Percentage Length Frequency

14 12 10

8 VIIg 6 All Other Areas Percent 4 2 0 11 16 21 26 31 36 41 46 51 56 61 66 71 76 81 94 104

Length (cm)

Figure 13.5 Dogfish (Scyliorhinus spp.) Length Frequencies. Area VIIg shows a spike for fish of <25cm, showing that juveniles make up a substantial proportion of the discards and that therefore, this area can be considered to be a nursery ground for dogfish. (Source: Irish Discard Observer Programme) 154 | ICES WGEF Report 2005

Table 13.10. Ray catches from Irish Groundfish Survey per ICES area, 1993–2004. Only rays identified to species level are included.

ICES Area SPECIES VIa VIIa VIIb VIIg VIIj Total Blonde Ray (BLR) 4 150 2 7 163 Cuckoo Ray (CUR) 112 176 51 14 2 355 Spotted Ray (SDR) 93 674 23 89 2 881 Thornback Ray (THR) 107 423 113 16 6 665 Undulate Ray (UNR) 3 2 5 Total 316 1425189 128 10976

800

700

600 BLR 500 CUR 400 SDR THR 300 UNR 200

100

0 VIaVIIaVIIbVIIgVIIj

Figure 13.6: Ray numbers per species per ICES area from Irish Groundfish Survey, 1993–2004. ICES WGEF Report 2005 | 155

14 Demersal elasmobranchs in the Bay of Biscay and Iberian Waters (ICES Subarea VIII and Division IXa)

The Cantabrian Sea (ICES VIIIc Division) is the southern part of the Bay of Biscay (ICES VIIIabd Divisions). Its continental shelf is characterised by its narrowness and by some remarkable bathymetric features (canyons, marginal shelves, etc.) compared to other adjacent areas such as the French coast of Bay of Biscay, characterised by a wide continental shelf with flat and soft bottoms very suitable for trawler fishing activity. In Portugal the artisanal and trawler fleet operates along the Portuguese continental coast (Division IXa), targeting wide number of teleost, crustaceans and deep-water sharks. Several species of rays are also landed mainly in the ports of Matosinhos, Peniche and Portimão.

There are no management stock definitions for any of three main species, either in Bay of Biscay or Iberian waters. Although the geographical distribution of these species is well known there aren’t still clear evidences to consider the populations of Bay of Biscay or Iberian waters (Subareas VIII and IX) as biological stocks different to the North Atlantic or Mediterranean populations. The information given in this section is a summary of the conclusions obtained in the project DELASS (Heessen, 2003) for the case study of S. canicula and L. naevus in these areas, trying to describe the distribution of each case study species' population and to identify self-contained stocks. These conclusions were obtained integrating the present knowledge in taxonomy, distribution and life-history parameters for each species.

Scyliorhinus canicula: It appears that lesser spotted dogfish populations would best be assessed as local populations, concluding that due to the availability of fisheries statistics and biological data, assessing this species within the Cantabrian Sea (VIII c) was appropriate.

Leucoraja naevus: As biological and fisheries data are most accurate and comprehensive for the Celtic Sea (VIIe-k) and Biscay Bay region (VIII), these areas should be used in a preliminary assessment of this species. The little information available on the distribution and biological parameters of R. clavata populations in Bay of Biscay and Iberian waters didn’t allow reaching any conclusion about the stock definition in these areas.

14.1 The fishery

The Spanish demersal fishery along the Cantabrian Sea and Bay of Biscay takes many species of rays with a wide variety of gears but mostly of the landings come from the by-catch of fisheries targeting other demersal species such as hake, monkfish and megrim. Although a wide number of rays and demersal sharks can be found in the landings, historically the most commercial elasmobranchs are two species of rays; Leucoraja naevus, Raja clavata and the small demersal shark Scyliorhinus canicula (lesser spotted dogfish). The fact that rest of elasmobranchs have a low commercial value and are taken as a by-catch, implies that traditionally these species were landed together in the same category, making it difficult to know the landings by species, as the case is for rays or deep water sharks.

The main gear in the subarea VIIIc is the bottom trawl fleet working on two kinds of fishing grounds: for gadoids and flatfish at depths of 100–300 m over the continental shelf and taking rays (R. clavata, L. naevus, R. montagui, R. brachyura, R. undulata and R. microocellata) and dogfish . In 1994, a total of 7089 t of elasmobranchs are caught by trawl fleet in Cantabrian Sea, of which 87% was discarded (Perez et al., 1996).

In Spain, lesser-spotted dogfish is, after the Rajidae, the most important elasmobranch species in the by-catch of the trawl fishery in the VIII Subarea. Most of these landings, (from 233 to 405 t per year in the period 1996–2004), come from the VIIIabd Divisions fished by the Basque otter trawler fleet (“baka” type). In the Divisions VIIIabd the annual landings into 156 | ICES WGEF Report 2005

Basque Country ports amounting on average 382 t of rays in the period from 1996 to 2004 (only 12 t in VIIIc in the same period) but the total rays landings of basque fleet are decreasing from year to year, from 631 t landed in 1998 to 264 t in 2004. As for the lesser spotted dogfish fishery, the otter trawler fleet (“baka” type) targeting hake, monkfish and megrim lands mostly of rays (between the 81% and 96% of total rays in the period 1996– 2004). The most abundant species are L. naevus and R. clavata representing respectively the 77% and 17% in the catch composition in the period 2000-2004. Small quantities of R. asterias, R. batis, L. fullonica, R. montagui, D. oxyrhinchus, R. undulata are also often landed. On the contrary S. canicula is a species usually discarded in the Spanish fishery in the Cantabrian Sea (VIIIc) and only 10–25% is actually landed (ICES, 2002a). As with rays the highest landings are those from bottom trawls (75%) followed by longline (21%) and gillnet (3%); occasionally there have been landings from purse seine or traps (Fernández et al., 2002).

In mainland Portugal (IXa), lesser-spotted dogfish is mainly caught by coastal trawlers and by the artisanal fishing fleet. Most of the landings are recorded under the generic name of Scyliorhinus spp., and annual landings have increased from around 500 t in 1986 to between 700 and 800 t in 1997–2001. In mainland Portugal, skates and rays are landed under the generic name of Raja spp. as bycatches of the artesanal and trawl segments of the commercial fleet (Heessen, 2003). The artesanal fleet, that comprises different types of fishing gear such as longline and gillnet, accounts for the highest landing records (75% of the total annual landings).

As the specimens are not discriminated at species level, a pilot sampling programme was carried out during 2001 in the two major ports with landings of Rajidae (Matosinhos and Peniche) to get a first estimate of species’ diversity landed in Portugal mainland (Bordalo- Machado et al., 2004). Then in 2003 and 2004, a minimum sampling programme was implemented (according to the EU council regulation 1543/2000) in the two above-mentioned ports and also at Portimão, in the south coast of Portugal. This programme allowed the estimation of the species composition, the number of individuals by length class and sex and individual total weight in the landings.

During 2004, the sampling effort comprises a total of 71 samples in Matosinhos, 309 in Peniche and 70 in Portimão. In both years of the minimum sampling programme, the same eight ray species were identified: Rostroraja alba, Raja brachyura, Raja microocellata, Raja clavata, Raja miraletus, Raja montagui, Raja undulata and Leucoraja naevus. R. brachyura and R. clavata were the most frequent species while R. miraletus was the most infrequent species sampled.

Two species, lesser-spotted dogfish Scyliorhinus canicula and bull huss S. stellaris are landed in the major ports of Division IXa under the generic name of Scyliorhinus spp. Although it is believed that S. canicula is the dominant species in the landings, the percentage of mixture is not known.

Traditionally, the French fishery was limited to the continental shelf of the Celtic Sea, the Channel and Bay of Biscay, and only two species of sharks (S. acanthias and S. canicula) and one ray (L. naevus) were particularly important in the catches (about 60 to 70% of elasmobranch landings). Since 1990, the trawlers have also worked on the continental slope and deep-water species have appeared on the fish markets. About twenty-five species of elasmobranchs are currently landed on the Atlantic coast of France, and French fleets land a greater weight of these fish from Northeast Atlantic waters than any other European country. Most elasmobranch landings are taken as a by-catch and are landed by all categories of fishing boats, using various gears – longline, gill net, trawl – depending on the target species of teleosts. Since 1980, trawls have produced between 80 and 90% of the French landings, long lines 4 to 8% and gill nets 3 to 6%. In France the cuckoo ray has contributed over 30% of the total ray catch in recent years, and comes mainly from the southern part of the Celtic Sea and

ICES WGEF Report 2005 | 157

the northern part of the Bay of Biscay. Most of the French catches of rays are taken as by- catch during bottom trawling, however the thornback ray is often the target of directed seasonal fisheries by France in these areas. The lesser spotted dogfish landings reported by France in subarea VIII are around 1 t by year, a very few compared with Spanish ones, probably because this species is discarded by the French trawler fleet.

14.1.1 Landings data

The ray landings in Subarea VIII (Cantabrian Sea and Bay of Biscay) and IX (a) for the period 1973 to 2004 are given in the Tables 14.1.1 and 14.1.2. Historically the main countries reported international landings from 1973 in Subarea VIII are France (data reported until 2001) and Spain (data reported from 1978 onwards), and Portugal in Subarea IX. In the Table 14.1.3 a summary of combined landings for both areas is shown. On average 4209 t of rays by year have been landed in Biscay, Gulf and Iberian waters since 1973, with a maximum of 6030 t registered in 1988. Some other countries as Belgium, Netherlands and UK contribute with minor ray landings in these areas. The lesser-spotted dogfish landings in Subarea VIII and IXa Division reported to the WG are also shown in the Tables 14.1.4 and 14.1.5.

The information about the historical landing series of other elasmobranch species such as Gaeorhinus galeus (tope shark), Mustelus mustelus and Mustelus asterias (smooth hounds), and Squatina squatina (angel shark) are fairly imprecise ( Tables 14.1.6 to 14.1.11)

Of these species, only smooth hounds are landed in significant quantities in subarea VIII, mainly by the French and Spanish fleets (about 400 t per year from 2000 to 2003). Even though the angel sharks landings always have been very low in this area there are no landings registered in these waters in last 15 years, and only 66 t of this species were landed recently in 2002 in subarea IX.

Some of the countries who report annual landings in Subarea VIII provide also partial information (only for last five years) about the species-specific landings (see Table 14.1.12). According with this Table by far the most important species landed by these countries are L. naevus, R. clavata, and R. brachyura.

14.1.2 Advice and management

ACFM has never provided advice in this area.

14.2 Biological information

14.2.1 Length frequencies

The biological data collected refers to length distributions and also weight/length relationships for the two main ray species and lesser-spotted dogfish landed in the Basque Country for the otter “baka” trawler fleet in VIIIabd Divisions. The Figures 14.2.1a and 1b show the length distribution estimations of three species combined by sex. This estimation was carried out from 2000 to 2002 in a sampling programme founded for the DELASS project, and since 2003 thanks to the European minimum sampling programme. The samplings were made in Ondarroa, the most important port for elasmobranch landings in the Basque Country and the estimations was carried out raising the length samples to the total landing by area and gear. There was little variation in the mean length of rays along the four years with L. naevus ranges from 48 cm to 52 cm and from 57 cm to 64 cm for R. clavata. The sex composition of landings for both species is very variable throughout the years, in L. naevus the proportion of females goes from 43% in 2002 to 68% in 2003 and from 56% to 70% in R. clavata. The mean length in the same period for males of S. canicula was 58 cm and 56 cm for females and both sexes show a similar length range. The female proportion in the landings of this species remains fairly constant throughout the whole period (from 45% to 51%).

158 | ICES WGEF Report 2005

In the Cantabrian sea approximately 84% of R. montagui landings come from trawling, which catches specimens of total length ranging from 30 to 90 cm. Gillnet catches include small specimens less than 20 cm and some large individuals, while longline catches medium size specimens, mainly from 45 to 60 cm. The length distribution of R. clavata: in trawl landings of this species (80%) ranges from 32 to 95 cm. Gillnet, which represents around 6% of the landings, catches specimens mainly form 50 to 70 cm. Longline (14%) also covers a length range as wide as trawl, but most of the individuals landed are 45 to 55 cm of total length. Only specimens of L. naevus from longline (6%) and trawl (94%) have been sampled, there are no gillnet landings recorded for this species during the study period. The length distribution of the trawl catch of L. naevus ranges from 35 to 77 cm, while longline catches medium size specimens from 47 to 67 cm.

The length distribution of S. canicula in Cantabrian Sea shows that most the specimens landed are above 40 cm, ranging up to 66 cm. No significant differences exist among the catches of the different fishing gears, the mean size of specimens caught by trawl, longline and gillnet being 53.6 cm, 55.2 cm and 54.0 cm respectively. Considering that first maturity length of females is 54.5 cm, most specimens landed are adults.

14.2.2 Tagging data and biometric relationships

A tagging program carried out since 1993 in the Cantabrian Sea. A total of 6 619 lesser spotted dogfish have been tagged with T-bar anchor tags and 2.3% of recaptures received to date. The maximum distance recorded by an individual has been 158.9 miles while the 70 % of the specimens recaptured were in less than 15 miles and 56 % less than 10 miles (Rodríguez-Cabello et al., 2001). It seems that the species' distribution is continuous but with localised aggregations which are consistent over time. In the Cantabrian Sea, data analysed from a series of bottom trawl surveys carried out annually show that there is no clear discontinuity in the distribution of lesser spotted dogfish in this area. This species usually shows unisexual aggregations and, less frequently, aggregations by size (de la Gándara et al., 1994). The spatial distribution of adults obtained from surveys carried out in different seasons showed no differences at all. On the contrary, juveniles were much less abundant than adults, independent of the season, but they were found in high concentrations in the south eastern corner of the Bay of Biscay. The minor abundance of juveniles compared to adults is probably due to the fact that the fishing gear used has poor access to this fraction of the population because juveniles are mainly distributed over rocky bottoms.

A study carried out in 1994 (Rodriguez-Cabello et al., 1998) revealed that the maximum proportion of egg-carrying females was found in April, May and June, however the low number of specimens sampled in autumn did not allow to determine whether differences exist with regard to spawning intensity throughout the year. English surveys almost never catch juveniles, though hundreds of egg cases are caught in the Bristol Channel. There have been few studies on life history parameters, though further north specimens grow bigger than in Spanish waters. Spawning is supposed to take place in shallow waters near the coast (Compagno, 1984; Muñoz-Chápuli, 1984; Capapé et al., 1991). Unfortunately, we do not have information from shallow waters or hard bottoms in the southern area of the Bay of Biscay, so we cannot confirm if juveniles are concentrated in these areas along the coast. Another hypothesis suggests that spawning takes places mainly on the slope, for example D’Onghia et al. (1995) found juveniles and adults of both sexes and sizes together at depths greater than 200 m in the north Aegean Sea. Because lesser spotted dogfish do not show a clear geographical migration, an assessment could in principle be based on any arbitrary area.

Biometric relationships for total or fork length/total or gutted weight for and relationships between total length/total or gutted weight and total length/width disc for several ray species and S. canicula collected from Divisions VIIIabd, VIIIc and IXa are presented in the Figures 14.2.2a, 2b and in the Table 14.2.1.

ICES WGEF Report 2005 | 159

14.2.3 Surveys

The Cantabrian Sea has many species of demersal elasmobranchs. Bottom trawl surveys and the main commercial fisheries carried out in this area (period 1997–1999) suggest that elasmobranchs play an important role in the ecosystem, since they are relatively abundant in all types of habitat (Sánchez, 1993; Sánchez et al., 1995, 2002). The main elasmobranch species that inhabit the continental shelf of the Cantabrian Sea, based on the bottom trawl surveys, include R. clavata, R, montagui and S. canicula, with Galeus melastomus more abundant on the outer shelf and deep-water sharks (e.g. E. spinax and D. calcea) off the shelf edge (Table 14.2.2).

14.2.4 Landings per unit of effort

Data of ray LPUE (Landings per unit of effort) for the Baka otter trawler fleet fishing in Divisions VIIIabd, (Ondarroa port in the Basque Country, Spain) in the period 1996–2004 shows that the LPUE reached a maximum in 1998 with 207 kg/day and a minimum of 103 kg/day in 2004 (Figure 14.2.3). These values are higher than the S. canicula’s LPUE until 2002. For the same period and for the same fleet and increase in the LPUE of S. canicula from 1996 to 2002 (maximum 168 kg/day) is observed. The values of LPUE go down in 2003 and 2004 but still remain higher than in the period 1996–2001, and with similar values to rays. Notice that the data shown in the Figure 14.2.3 are referred to landings and not to catches.

The other hand the Figure 14.2.4 shows the distribution of rays and lesser spotted dogfish CPUEs (Catches per unit of effort) obtained from the Baka Otter trawler log books operating in Bay of Biscay (VIIIabd) and also in subareas VII and VI (preliminary data).

14.2.5 Discards

Some information on elasmobranch discards by several Basque Country fleets was obtained in a study in 2000 (Lart et al., 2002). More than 80% in number, and 45% in weight, of lesser- spotted dogfish are discarded by the otter trawler fleet in VIIIabd Divisions, due to their small size and low market price (Table 14.2.3). About 20% of the rays in numbers, but only 7% of the ray catches in weight, were discarded due to their small sizes. No information on the ray discards by species is available, except for L. naevus. For this species, 40% of the catch in number was discarded, but only 12% in weight, i.e., only the small specimens. No discards of other sharks (Squalidae, Triakidae) were observed, but their catches were also very low (Figure 14.2.5).

A study carried out in 1994 to estimate the discards of the Spanish fleet in ICES area VIIIc revealed that almost the 90% of the total catch of dogfish is discarded, later studies made in 1999 and 2000 estimated the proportion of discards in 77 % and 83 % respectively (Pérez et al., 1996). For rajidae species R. montagui, R. clavata and L. naevus the values obtained were 20%, 25 % and 33 % respectively (Table 14.2.4).

14.2.6 Growth parameters

There is a little information about growth parameters in elasmobranchs species of Bay of Biscay and Iberian Waters. The observed maximum sizes of S. canicula differ greatly from one area to another. Generally, the biggest specimens are found in the northern area of its Atlantic distribution (e.g. North Sea and Irish Sea) Estimates for the von Bertalanffy equation and observed maximum lengths for some Atlantic areas are given in Table 14.2.5

Table 14.2.6 shows the available growth information available for thornback ray R. clavata from Division IXa. Specimens between 138 and 885 mm TL were obtained from research surveys and commercial landings (Peniche) between September 2003 and December 2004 and the Von Bertalanffy growth parameters were obtained for both sexes (Serra Pereira, 2005).

160 | ICES WGEF Report 2005

14.3 Stock assessment

14.3.1 Previous assessments

Two previous assessments for L. naevus in subareas IV and VIII and for S. canicula in VIIIc were attempted in the DELASS project (Heessen, 2003) and in the meeting of SGEF 2002 (ICES, 2002a) respectively.

Data of catch, effort, length frequency, French EVHOE survey and discards were available for the analysis of stock of L. naevus. Three models were selected for the assessment GLM analysis, Surplus production model and Catch curve analysis. The overall conclusion of this assessment was that these three models shown conflicting indications about the trends for this stock. In the absence of a long-term time series, it was not possible to evaluate where the current status of the stock is in relation to historical levels. Some recommendations to improve biological and fishery information and to clarify the stock definition were suggested in order to address further the assessment of cuckoo ray:

In the case of S. canicula tagging data, landings and effort for the period 1996–2001, CPUE series since 1991, length distributions and trawl survey abundance indices were available for the analysis. Dynamic surplus production, Separable VPA and Survey-only models were chosen for this assessment.

Although these models were considered as useful tools for the assessment, neither of the results obtained by the models was considered satisfactory for this species due to the shortage of biological information and difficult to collect long time series of landings and effort. More detailed information can be extracted from de final report of the SG (ICES, 2002a).

14.4 Management considerations

Survey index and commercial CPUEs for S. canicula in carried out in VIIIc Divison indicate that the population of this specie has been increased from 1996 to 2001 (Figure 14.8.1). Unfortunately since 2001 there is not more available information for this area, however the LPUE data for trawler fleet in Bay of Biscay shows that 2002, 2003 and 2004 are three of the best years of the series (Figure 14.2.3). In accordance with this data, lesser spotted dogfish catch rates (CPUEs) higher than 1000 kg/hour can be observed in some statistical rectangles of Bay of Biscay in 2004 (Figure 14.2.4). All this information suggests that in last years the population of S. canicula in subarea VIII may be increasing or at least is in stable condition.

The situation of rays abundance in these areas is less clear, but information of landings and CPUEs seems to suggest a stable situation of these species in Cantabrian Sea and Bay of Biscay.

However, in order to clarify these considerations, better information on species composition of landings and about French and Spanish surveys in subarea VIII are necessary.

ICES WGEF Report 2005 | 161

Table 14.1.1 Total landings (t) ofRajidae in area VIII 1973 1974 1975 1976 1977 1978 1979 1980 1981 1982 1983 1984 1985 1986 1987 1988 1989 1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 200204* 2003* 20 Belgium .. . 1+2 . 22 . 3 . 151212411229126111161121118 France 3935 3184 999 1063 1363 1492 1850 1696 1518 1742 2200 2479 2557 2639 2572 2344 2321 2162 1956 1734 1653 1746 1934 1822 2089 1988 485 2830 2784 791 Netherlands ...... +.1. Portugal 6188844611811710445 264 Spain 15 38 1428 1318 972 1236 1098 1178 1320 1050 1120 712 540 962 1319 1143 905 881 1135 670 272 264 UK (E&W_NI_+) ...... 1+.21567795720+7216252122761372344 UK (Scotland) ...... +...... Total of submitted data 3935 3184 999 1064 1363 1509 1850 1698 1559 3170 3521 3453 3809 3809 3836 3741 3411 3294 2680 1741 1677 1784 2512 2829 3497 3165 1412 3722 3939 1486 287 536

Table 14.1.2 Total landings (t) of Rajidae in area IX 1973 1974 1975 1976 1977 1978 1979 1980 1981 1982 1983 1984 1985 1986 1987 1988 1989 1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 France 12 n.s. Portugal 1264 1107 1378 1510 1355 1035 1273 1622 1579 1562 1529 1893 1795 1693 2694 2103 1731 1533 1375 1553 1613 1369 1433 1534 1512 1485 1420 1528 1591 1521 1598 1446 Spain 380 114 851 430 644 389 295 347 186 451 671 440 763 58 143 197 276 226 421 301 Total of submitted data 1264 1107 1378 1522 1355 1415 1273 1622 1693 2413 1959 2537 2184 1988 3041 2289 2182 2204 1815 1553 1613 1369 2196 1592 1655 1682 1696 1754 2012 1822 1598 1446

Table 14.1.3 Combined Landings (t) of Rajidae in Biscay and Iberian Waters 1973 1974 1975 1976 1977 1978 1979 1980 1981 1982 1983 1984 1985 1986 1987 1988 1989 1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 2003 200 4 Belgium . . . 1+2 . 22 . 3 . 151212411229126111161121118 France 3935318499910751363149218501696151817422200247925572639257223442321216219561734165317461934182220891988ns18861983 . . 0 Netherlands ...... +.1. Portugal 1264 1107 1378 1510 1355 1035 1273 1622 1579 1562 1529 1893 1795 1693 2700 2121 1739 1541 1379 1557 1619 1380 1441 1545 1519 1495 1424 1532 1596 1521 1598 171 0 Spain . . . . . 395 . . 152 2279 1748 1616 1625 1393 1525 1506 1501 1791 1152 . . . 1303 1019 1462 1340 1181 1106 1556 971 272 264 UK (E&W_NI_+) ...... 1 + . 2 15 67 79 57 20 + 7 2 16 25 21 22 76 13 7 2 3 4 4 UK (Scotland) ...... +...... Total of submitted data 5199 4291 2377 2586 2718 2924 3123 3320 3252 5583 5480 5990 5993 5797 6877 6030 5593 5498 4495 3294 3290 3153 4708 4420 5152 4847 2623 4532 5150 2516 1885 198 1

* 2003 and 2004 in Spain only Basque Country landing 162 | ICES WGEF Report 2005

Table 14.1.4 Lesser Spotted Dogfish (Scyliorhinus canicula) landings (t) in Area VIII

1996 1997 1998 1999 2000 2001 2002 2003* 2004* Belgium 8,5 France . . . 1 0 0 1 NA Spain 417 458 536 448 481 513 520 384 318 UK E&W) 2 Total 417 458 536 449 481 513 521 386 318

Table 14.1.5 Lesser Spotted Dogfish (Scyliorhinus canicula) landings (t) in Area IX

1996 1997 1998 1999 2000 2001 2002 2003 2004 Spain 3 6 19 34 71 39 39 NA Portugal 667 691 689 882 757 734 673 658 624 Total 670 697 708 916 828 773 712 658 624

• 2003 and 2004 in Spain only Basque Country landings ICES WGEF Report 2005 | 163

Table 14.1.6. - Tope shark (Galeorhinus galeus) - ICES Area VIII

1978 1979 1980 1981 1982 1983 1984 1985 1986 1987 1988 1989 1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 France . 237 . . . 63 119 52 103 97 66 39 34 38 34 40 54 44 78 40 46 + 71 58 49 60 n.a. Spain ...... 9 13 10 n.a. Spain (Basque Country) ...... 9 6 10 10 UK (E&W_NI_+) + + + + + + + + + + + ...... 1 + 3 n.a. Total + 237 + + + 63 119 52 103 97 66 39 34 38 34 40 54 44 78 40 46 + 71 77 68 83 10

Table 14.1.7. - Smooth hounds nei (Mustelus spp.) - ICES Area VIII

1979 1980 1981 1982 1983 1984 1985 1986 1987 1988 1989 1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 Belgium ...... + France 11 . . 14 56 44 25 47 59 66 19 22 50 36 51 70 54 98 113 158 + 231 272 351 145 n.a. Portugal ...... + . . . 1 Spain ...... 66 61 64 50 67 78 110 93 n.a. Spain (Basque Country) ...... 34 27 53 56 57 46 61 58 85 58 56 Total 11 . . 14 56 44 25 47 59 66 19 22 50 36 51 104 81 217 230 279 96 359 408 546 296 57

Table 14.1.8. - Smooth hounds nei (Mustelus spp.) - ICES Area IX

1999 2000 2001 2002 2003 2004 Portugal 72 39 41 43 50 32 Total 72 39 41 43 50 32

164 | ICES WGEF Report 2005

Table 14.1.9 - Smooth hound (Mustelus mustelus) - ICES Area IX

1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 Portugal 5 + + + 1 5 2 4 4 2 2 2 1 1 Total 5 + + + 1 5 2 4 4 2 2 2 1 1

Table 14.1.10. - Angel shark (Squatina squatina) - ICES Area VIII

1978 1979 1980 1981 1982 1983 1984 1985 1986 1987 1988 1989 1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 2003 France 1 . . . 3 2 5 18 4 6 4 2 1 . . 1 1 . . . . + 1 + + + UK (E&W_NI_+) ...... 2 ...... Total 1 . . . 3 2 5 18 4 6 4 4 1 . . 1 1 . . . . + 1 + + +

Table 14.1.11 - Angel shark (Squatina squatina) - ICES Area IX

2002 Spain 66 Total 66

ICES WGEF Report 2005 | 165

Table 14.1.12.Species-specific landings (rays and skates in t) by country in Subarea VIII, an XI (a) all gears combined. These data are included in the Table 14.1.1.

Country year area T. marmorata D. batis D. oxyrinchus L. circularis L. fullonica L. naevus R. clavata R. microocellata R. montagui R. undulata D. pastinaca M. aquila R. asterias R. brachyura Raja miraletus Rostroraja alba miscellaneous Raja spp.

France 1999 VIII 24.1 1.3 0.2 16.8 0.3 318.7 74.6 0.3 46.0 0.2 0.4 1.5 0.4

France 2000 VIII 8.6 4.5 0.6 54.5 2.5 748.8 67.9 0.0 53.1 1.4 0.8 0.3 0.7

France 2001 VIII 3.1 3.8 0.3 46.7 7.2 636.8 36.9 0.6 62.4 1.6 0.8 0.1 0.6

France 2002 VIII 5.0 12.7 16.3 51.1 5.1 614.1 38.9 0.8 46.7 0.1 0.4 0.1 0.0 Belgium 2002 VIIIab 14.5 6.4 0.1 Spain (Basque Country) 2000 VIII 6.3 4.0 250.1 39.1 2.0 0.4 Spain (Basque Country) 2001 VIII 7.6 0.12 26.4 229.7 85.1 4.9 0.1 Spain (Basque Country) 2002 VIII 242.5 54.4 17.5 Spain (Basque Country) 2003 VIII 12.2 229.6 37.6 4.1 0.1 Portugal 2002 IXa 12.7 2.4 1506 Portugal 2003 IXa 18 351 78 56 126 578 2 Portugal 2004 IXa 113 516 95 82 108 532 17 5

166 | ICES WGEF Report 2005

Table 14.2.1. Biometric relationship of several ray species of Subarea IX collected during different sampling programmes , a) total weight (TW) b) total length (TL).

ICES Relation Sample size Species name Param. estimates R Subarea type (Total length range) F a=3x10-6; b=3.136 0.937 n=37, (520; 910 mm)

Raja undulata TW= a*TLb IXa M a=1x10-5; b=2.953 0.964 n=32, (428; 910 mm) F a=2x10-6; b=3.168 0.908; n=83, (420; 905 mm)

Raja clavata TW= a*TLb IXa M a=4x10-5; b=2.735 0.953 n=70, (380; 840 mm) F a=3x10-6; b=3.163 0.981; n=83, (377; 1020 mm)

Raja brachyura TW= a*TLb IXa M a=4x10-6; b=3.091 0.989 n=72, (362; 1005 mm) F a=2x10-6; b=3.207 0.984; n=34, (415; 785 mm)

Raja microocellata TW= a*TLb IXa M a=7x10-6; b= 2.991 0.991 n=34, (395; 760 mm) Table 14.2.2 Main species of elasmobranchs caught during groundfish surveys in the Cantabrian Sea ranked by biomass index (kg/30 min. haul for the period 1997-1999) and percentage of participation in each trophic group in the trophodynamic model (X=<1%). The habitat preference was used in the Ecospace spatial-temporal simulations (Source: Sánchez et al., 2002).

Abundance Trophic

indices group Family Specie Kg/haul No./haul Dogfish Rays Habitat preference

Scyliorhinidae Scyliorhinus canicula 3.093 10.396 80% Inner and middle shelf Rajidae Raja clavata 0.999 0.926 50% Coastal and inner shelf Scyliorhinidae Galeus melastomus 0.600 4.942 15% Outer shelf Rajidae Raja montagui 0.565 0.664 30% Coastal and inner shelf Squalidae Squalus acanthias 0.369 0.085 X Middle and outer shelf Rajidae Leucoraja naevus 0.183 0.298 15% Inner and middle shelf Squalidae Deania calcea 0.173 0.432 X Shelf break Squalidae Etmopterus spinax 0.099 1.758 X Shelf break Rajidae Raja undulata 0.057 0.024 X Coastal and inner shelf Squalidae Scymnodom ringens 0.045 0.129 X Shelf break Myliobatidae Myliobatis aquila 0.028 0.022 X Coastal and inner shelf Scyliorhinidae Scyliorhinus stellaris 0.022 0.123 X Inner and middle shelf Hexanchidae Hexanchus griseus 0.016 0.010 X Middle and outer shelf Torpedinidae Torpedo marmorata 0.013 0.009 X Coastal and inner shelf Triakidae Galeorhinus galeus 0.001 0.004 X Inner and middle shelf Triakidae Mustelus mustelus 0.001 0.004 X Inner and middle shelf Rajidae Raja brachyura 0.000 0.004 X Coastal and inner shelf Rajidae Leucoraja circularis 0.000 0.002 X Inner and middle shelf

ICES WGEF Report 2005 | 167

Table 14.2.3. Estimated catch composition -landings and discards- of sharks and rays taken by some Basque trawl fleets from ICES Divisions VIIIabd in 2000.

Numbers (x 1000) Percentage Weights (Ton of total catch Discarded + Retained + Total Species by Number Discarded Retained C.V C.V Catch Discarded Raja spp. 3.9 ±0.8 15.9±0.2 19.8 20 2.2 30.1 S. canicula 72.0±0.3 16.3±0.3 88.3 82 19.1 23.7 L. naevus 4.7±0.5 6.2±0.3 10.9 43 0.9 6.4 R. clavata 0.14±1.39 0.25±0.71 0.39 36 0.02 0.32

Table 14.2.4. Catch and discards of some elasmobranch species by the Spanish trawl fleet in ICES sub-area VIIIc expressed in kg per 100 fishing hours, 1994.

Species Catch Discard %Discard D. calceus 6 6 100 G. melastomus 194 177 91 G. galeus 1 R. clavata 34 8 24 R. montagui 12 2 17 L. naevus 6 1 17 Raja spp. 1 0 0 S. canicula 249 225 90

Table 14.2.5.Von Bertalanffy growth parameters and maximum length of Scyliorhinus canicula of Atlantic waters.

L max observed Area L∞ K Male Female Author North Sea 88.0 0.20 Jennings et al. (1998) Ireland 82.7 0.15 Henderson & Casey (In press) Bristol Channel 66 67 Ellis & Shackley (1997) English Channel 70 70 Ford (1921) Roscoff 66 66 Faure-Fremiet (1942) Concarneau 72 72 Faure-Fremiet (1942) Atlantic 68 68 Leloup & Olivereau (1951) Bay of Biscay 88.8 0.13 Rodriguez-Cabello et al.(1998)

Table 14.2.6. Age information on thornback ray R. clavata from Portugal mainland (Division IXa). Min=minimum length (mm); max=maximum length (mm); Linf (mm),k (year-1) and t0 (year)=von Bertalanffy growth parameters.

min max Linf k t0 males 152 769 1140 0.12 -0.59 females 138 885 1320 0.10 -0.23 168 | ICES WGEF Report 2005 L. naevus length frequency R. clavata length frequency 35000 4000 n= 753 n= 251 30000 3500

25000 2000 3000 2000

2500 20000 2000 15000 number number 1500 10000 1000

5000 500

0 0

2 8 8 1 7 0 6 2 1 7 3 6 2 30 34 38 4 46 50 54 5 62 66 70 74 78 82 86 90 94 98 06 1 2 24 2 3 33 3 39 4 45 48 5 54 5 60 6 6 69 7 75 102 1 110 length (cm) length (cm)

L. naevus length frequency R. clavata length frequency

35000 4000 n= 530 n= 289 30000 3500

25000 2001 3000 2001

20000 2500

2000 15000 number number 1500 10000 1000 5000 500 0 0 1 7 0 6 2 1 7 3 9 2 18 2 24 2 3 33 3 39 4 45 48 5 54 5 60 6 66 6 7 75 0 8 2 6 0 4 2 6 0 8 2 6 0 4 8 3 34 3 4 4 5 5 58 6 6 7 74 7 8 8 9 9 9 06 length (cm) 102 1 110 length (cm)

L. naevus length frequency R. clavata length frequency 35000 n= 223 4000 30000 n= 88 3500 2002 25000 3000 2002

20000 2500

2000 15000 number number 1500 10000 1000 5000 500

0 0 8 7 6 2 1 7 3 6 2 1 21 24 2 30 33 3 39 4 45 48 5 54 5 60 6 6 69 7 75 2 8 2 6 0 30 34 38 4 46 50 54 5 62 66 70 74 78 82 86 90 94 98 0 length (cm) 10 1 11 length (cm)

L. naevus length frequency R. clavata length frequency

35000 4000 n= 201 n= 88 30000 3500

3000 25000 2003 2003

2500 20000 2000 15000 number number 1500 10000 1000

5000 500

0 0

1 4 0 3 9 5 8 4 0 9 5 18 2 2 27 3 3 36 3 42 4 4 51 5 57 6 63 66 6 72 7 30 34 38 42 46 50 54 58 62 66 70 74 78 82 86 90 94 98 102 106 110 length (cm) length (cm)

Figure 14.2.1a. L.naevus and R. clavata length distributions of VIII Subarea landed by the otter trawler fleet in the Basque Country from 2000 to 2003. n= number of individual sampled.

ICES WGEF Report 2005 | 169

S. canicula length frequency S. canicula length frequency

90000 90000 n= 1419 n= 880 80000 80000

70000 2000 70000 2001

60000 60000

50000 50000

40000 40000 number number 30000 30000

20000 20000

10000 10000

0 0

4 7 0 3 6 9 2 5 8 4 7 0 3 6 9 2 5 8 32 35 38 41 4 4 5 5 5 5 6 6 6 71 74 77 80 32 35 38 41 4 4 5 5 5 5 6 6 6 71 74 77 80 length (cm) length (cm)

S. canicula length frequency S. canicula length frequency

90000 90000 n= 402 n= 375 80000 80000

70000 2002 70000 2003

60000 60000

50000 50000

40000 40000 number number 30000 30000

20000 20000

10000 10000

0 0

6 9 2 5 8 1 4 7 0 7 0 8 1 4 7 0 32 35 38 41 44 47 50 53 5 5 6 6 6 7 7 7 8 32 35 38 41 44 4 5 53 56 59 62 65 6 7 7 7 8 length (cm) length (cm) Figure 14.2.1b. S. canicula length distributions from VIII Subarea landed by the otter trawler fleet in the Basque Country from 2000 to 2003. n= number of individual sampled.

170 | ICES WGEF Report 2005

L. naevus L. naevus Total Length/Total Weight Disc Width/Total Length

3000 400

350 y = 0,5932x - 11,682 2500 3,1332 y = 0,000002773x 2 R = 0,983 2 300 2000 R = 0,925 n=53 n=678 250 1500 200

150 1000 Disc WidthDisc (cm) Total Weight (g) Weight Total 100 500 50

0 0 0 100 200 300 400 500 600 700 800 0 100 200 300 400 500 600 700 Total Length (mm) Total Length (cm)

R. clavata R. clavata Total Length/Total Weight Disc Width/Total Length 14000 700

3,169271312 y = 0,7167x - 3,4304 12000 y = 0,000002371x 600 2 2 = 0,9791 R = 0,953 R 10000 500 n=23 n=296 8000 400

6000 300 Disc Width (cm) Width Disc Total Weight (g) Weight Total 4000 200

2000 100

0 0 0 200 400 600 800 1000 1200 1400 0 100 200 300 400 500 600 700 800 900 Total Length (mm) Total Length (cm)

S. canicula Total Length/Total Weight

1600 y = 26,217x - 789,43 1400 R2 = 0,692 1200 n=1234 1000

800

600

total weight (g) 400

200

0 35 40 45 50 55 60 65 70 75 80 Total length (cm)

Figure 14.2.2a. L.naevus, R.clavata and S. canicula Total length/Total weight and Disc witdh/Total length relationships from VIII Subarea landed by the otter trawler fleet in the Basque Country from 2000 to 2003.

ICES WGEF Report 2005 | 171

TL TL = Total Length (cm) WL= Wing Length (cm)

DL = Disc Length (cm) dL

TW = Total weight (g) wL WW= Wing weight (g)

Raja clavata Raja montagui Leucoraja naevus Range TL= 17-84 cm Range TL= 25-86 cm Range TL= 20-66 cm N= 443 N= 464 N= 556

WL = 0.33 TL - 0.9383 WL = 0.2919 TL + 0.2516 WL = 0.2305 TL + 0.2003 r 2 = 0.9668 r 2 = 0.9197 r 2 = 0.9083

DL = 0.7004 TL + 0.0773 DL = 0.6491 TL + 1.4817 DL = 0.5734 TL - 0.4038 r 2 = 0.9761 r 2 = 0.9495 r 2 = 0.9674

WW = 0.2415 TW + 8.339 WW = 0.2422 TW + 11.97 WW = 0.1941 TW + 8.1796 r 2 = 0.9464 r 2 = 0.9650 r 2 = 0.9412

Note: There are no conversion factors between gutted and live weight, since this species is usually landed as wings only, or whole but not gutted.

TL = Total Length (cm) TW = Total weight (g) GW= Gutted weight (g)

Sex combined Males Females Range TL= 21-72 cm Range TL= 21-72 cm Range TL= 22-64 cm Range GW= 20-1066 g Range GW= 20-1066 g Range GW= 37-780 g

TW = 1.165 GW + 15.679 TW = 1.156 GW + 8.282 TW = 1.290 GW - 16.160 (*) r 2 = 0.9813 n=856 r 2 = 0.9875 n=520 r 2 = 0.9859 n=336

TW = 0.0021 TL 3.1189 TW = 0.0018 TL 3.1573 TW = 0.0016 TL 3.2037 r 2 = 0.9749 n=899 r 2 = 0.9811 n=562 r 2 = 0.9757 n=337

GW = 0.0019 TL 3.1009 GW = 0.0017 TL 3.1307 GW = 0.0019 TL 3.1009 r 2 = 0.9774 n=858 r 2 = 0.9783 n=521 r 2 = 0.9741 n=337

(*) TW = 1.2565 GW

Figure 14.2.2b. Biometric relationships for some rays and S. canicula from the Cantabrian Sea (VIIIc).

172 | ICES WGEF Report 2005

250

200 )

150

100 LPUE landings (kg/day landings LPUE 50

0 1996 1997 1998 1999 2000 2001 2002 2003 2004

Rays BAKA trawl-ON-VIIIa,b,d S. canicula BAKA trawl-ON-VIIIa,b,d

Figure 14.2.3. Rays and Lesser spotted dogfish LPUE (landings in kg/day) of Baka otter trawl landing in the Ondarroa port (Basque Country (Spain)) in the period 1996–2004.

18º 18º 20ºW 16° 14º 12º 10° 8º 6º 4º 2°W 0° 2° E 4º 6º 8º 10°E 20ºW 16° 14º 12º 10° 8º 6º 4º 2°W 0° 2° E 4º 6º 8º 10°E 65º 65º 58 58

56 56

63º 63º 54 54

52 52

61° 61° 50 50

48 48

59º 59º 46 46

44 44

57º 57º 42 42

40 40

55° 55° 38 38

36 36

53º 53º 34 34

32 32

51° 51° Scyliorhinus canicula 30 Rays 30 CPUEs (kg/hour) 2004 CPUEs (kg/hour) 2004 "Baka" otter trawl 28 "Baka" otter trawl 28 49º 49º 26 26 1- 50 kg/hour 1- 50 kg/hour

24 24 50-100 kg/hour 50-100 kg/hour 47º 47º 22 22 100- 1000 kg/hour 100- 1000 kg/hour 20 20

45° > 1000 kg/hour 45° > 1000 kg/hour 18 18

16 16

43º 43º 14 14

12 12

41° 41° 10 10

08 08

39º 39º 06 06

04 04

37º 37º 02 02

00 00 C9 D1D3 D5D7 D9 E1 E3E5 E7 E9 F9 F1 F3F5 F7 C9 D1D3 D5D7 D9 E1 E3E5 E7 E9 F1 F3F5 F7 F9 Figure 14.2.4. Spatial distributions by statistical rectangle of S. canicula and rays CPUEs (Catches per effort unit in kg/hour) by the Basque trawler fleet in subareas VIII, VII and VI in 2004 (preliminary data). ICES WGEF Report 2005 | 173

Lesser Spotted Dogfish (Scyliorhinus canicula ) 10000 Discarded: 82%

Discarded Retained 8000

6000

4000 Frequency (n) (n) Frequency

2000

0 <101520253035404550556065> 70 Length (cm)

Cuckoo ray (Raja naevus ) 1000 Discarded: 43% Discarded Retained 800

600

400 Frequency (n) Frequency

200

0 <101520253035404550556065> 70 Length (cm)

Figure 14.2.5. Estimated length distributions of discarded and retained (a) S. canicula and L. naevus taken by the Basque "Baka" trawl fishery in Div. VIIIabd in 2000.

174 | ICES WGEF Report 2005

CPUE Aviles CPUE total Survey index Model cpue

CPUE 15

0 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 Years

Figure 14.8.1. Lesser-spotted dogfish in Division VIIIc (Cantabrian Sea). Schaeffer model predicted CPUE and three observed CPUE for the lesser-spotted dogfish. Data used to fit the model include only landings (Heessen, 2003).

ICES WGEF Report 2005 | 175

15 Demersal elasmobranchs in the Azores and Mid-Atlantic Ridge

15.1 The fishery

The Mid-Atlantic Ridge (MAR) (ICES area X, XII, XIV) is an extensive and varied area, which includes several types of ecosystems, abyssal plains, seamounts, active underwater volcanoes, chemosynthetic ecosystems and islands, as a natural extension of this large ecosystem. Thus, in the context of this report, this is mainly a natural deep-water environment where predominate the small-scale fisheries in the islands EEZ and industrial deep-sea fisheries in the international waters. Landings from the Azores fleets have been reported to ICES. Landings from MAR remains very small and variable and few vessels find the MAR fisheries profitable.

15.1.1 Advice and management applicable to 2003 and 2004

ACFM has never provided advice for these stocks.

15.1.2 The fishery in 2004

Demersal elasmobranchs species are caught in the Azores EEZ by a multispecies demersal fishery, using hand-lines and bottom longlines, and by the black scabbarfish fishery using bottom longlines (Pinho, 2005). The most commercially important elasmobranchs species caught and landed from these fisheries is Raja clavata. However, landings statistics of this species are not reported by species but mixed on a general ray category. Several other deepwater elasmobranch species are also taken as by-catch in this fishery (Centrophorus spp., Centroscymnus spp., Deania spp., Etmopterus spp. and Raja spp.), particularly whenever the gear fishes deeper than 600 m, yet most of these are discarded due to their low commercial value.

The black scabbardfish (Aphanopus carbo) fishery has an important associated by-catch of leafscale gulper shark (Centrophorus squamosus). Several other deepwater elasmobranch species are occasionally taken, but only in much lower numbers, such as birdbeak dogfish (Deania calceus), Portuguese dogfish (Centroscymnus coelolepis), gulper shark (Centrophorus granulosus), kitefin shark (Dalatias licha), shortnose velvet dogfish (Centroscymnus cryptacanthus) and bluntnose six-gill shark (Hexanchus griseus). These sharks are processed onboard, and only the livers and trunks are used.

During the 2001/2002 exploratory fishing of the orange roughy (H. atlanticus) in some seamounts of the Azores using bottom trawl several elasmobranch species were also recorded (Melo and Menezes, 2002). An incomplete list of the species caught from the 246 hauls includes Somniosus microcephalus, C. coelolepsis, C. crepidater, C. cryptacanthus, Pseudotriakis microdon, H. griseus, C. squamosus, C. granulosus, E. princeps, D. calceus, Scymnodon obscurus and D. licha.

Historically, several international fleets have been operated on MAR area at least since 1970s, like the URSS fleets targeting alfonsinos (Beryx spp.) and roundnose grenadier (Coryphaenoides rupestris). Exploratory fishing were also done by some countries since the 1990s, Faroes for orange roughy, Norwegian fisheries in the Reykjanes ridge and Spanish on Hatton bank. The reported landings from the area remains however very limited. For further information on deepwater elasmobranchs in this regian see Sections 3, 4 and 5.

The catches reported from each country, for the period 1980 to 2004 and from area X are given in Tables 15.1 and a historical time series of the landings presented on Figure 15.1.

176 | ICES WGEF Report 2005

15.2 Biological composition of the Landings

In the Azores there is no systematic sampling information from the fishery. Length samples began to be collected for Raja clavata during 2004 under the Port Minimum Sampling Program. However, few individuals have been sampled on this species. There is no information for the other species landed.

15.3 Fishery-independent information

There is a spring demersal bottom longline survey running on the Azores annually (1995– 2004). A comprehensive resume of the elasmobranchs species occurring in the area and fisheries associated as well as the available information on species distribution by depth, was presented to the working group for the Azores (ICES area X) (Pinho, 2005). More than 25 demersal demersal species are listed as occurring in the Azores. The species covers benthopelagic and benthic habitats from shallow to deep-water strata in areas around coastal of the islands, banks and seamounts. The more represented demersal elasmobranch species on this survey are Etmopterus spp., Raja clavata, and Deania spp. However, the survey is only design for Raja clavata. Annual abundance index (Figure 15.2) by depth strata (Figure 15.3) and length composition (Figure 15.4) have been provided to the working group for Raja clavata. It is a clearly shallow species (Figure 15.3) being more abundant until 200 m depth. It is more abundant on the coastal areas of the islands because the habitat requirement of the species is more limited on banks and seamounts areas. Abundance of Raja clavata in the Azores area (Figure 15.2) shows a decline trend until 2001 and an abrupt increase there after with a peak on 2003.

Length composition of the Deania and Etmopterus species from the Azores are presented in the Figure 15.5 and 15.6

Some information on elasmobranchs species recorded on MAR is available from bottom trawls and longline surveys conducted on four selected areas, ranging the 450-4300 m, from Iceland to Azores (Hareide and Garnes, 2001). Dipturus batis, Bathyraja pallida and Bathyraja richardsoni were the only rays species recorded. Several deep-water shark species were caught, Centrophorus spp., Etmopterus spp., Deania spp. Galeus spp. Dalatias licha, Hexanchus griseus and C. fabricii.

Results from the longlinger MS Loran survey, under the Mareco 2004 expedition, along the Mid-Atlantic Ridge (500–3300 m) shows that chondrichthyans (sharks, skates, rays, and chimeras) dominated the catch by a large margin (http://www.mareco.no/mareco_news/2005/bottomliving_top_predators_of_the_deep_atlantic_the_sharks,_ska tes,_rays_and_chimaeras). Some of the species recorded from the longline were Bathyraja pallida, Bathyraja richardsoni and Rajella bathyphila, Centrophorus squamosus, Centroscymnus coelolepis, Centroscymnus owstoni, Centroselachus crepidater, Etmopterus princeps, Galeus murinus, Pseudotriakis microdon, Somniosus microcephalus, Somniosus rostratus.

There is some evidence that Chondrichthyes (sharks, rays and rays) are very rare in abyssal depths (>3000 m) suggesting that the distribution of this species are fragmented around seamounts, ocean ridges and margins (Pried et al., 2005). Restricted depth distribution means that the core of abundance distribution of these species may be on the range of deep sea fisheries operations.

15.4 Discards

Although the different commercial and recreational fleets may catch a relatively high number of elasmobranchs species only a few number of them are landed in the Azorean ports, including the pelagic ones. This shortcoming in the Azorean elasmobranchs landing statistics

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may be explained due to the onboard fish processing and discards. Some proportion of Deep- water sharks taken in the Azores are usually gutted, finned, beheaded and also skinned. Only the trunks and, in some cases, the livers are used. Whenever these fish are landed, the real weight of the catch is clearly underestimated. Elasmobranch discards are thought to be considerably high in the demersal and black scabbard fishery (thornback ray, small-sized tope shark and most deepwater species), due to low commercial value. Discards are responsible for major underestimations in Azorean catch statistics regarding elasmobranchs.

15.5 Mean length, weight, maturity and natural mortality-at-age

Length weight relationship was derived for Raja clavata from survey data (Rosa et al., 2005) (Table 15.2). Studies on age and growth of Raja clavata were done in the Azores using vertebras (Rosa, 2002). Von Bertalanffy growth parameters estimated from mean lengths at age, determined by 191 vertebra readings (length range 29-93 cm) were Loo= 161.87, K= 0.06 and To=-3.03.

15.6 Management considerations

Rays landing in the Azores shows an increase trend, with two peaks in 1979 and 1998 (Figure 15.1) due to the increasing of the effort observed on the demersal fisheries along time. Abundance of Raja clavata from the Azores, estimated from bottom longline surveys, shows a decline trend until 2001 and an abrupt increase thereafter with a peak on 2003. The Azorean government implemented since 1998 management actions in order to reduce effort on shallow areas of the islands, including a licence threshold based on the requirement of the minimum value of sales and a creation of a box of three miles around the islands areas with fishing restrictions by gear (only hand lines are permitted) and vessel type. Under the Fisheries Common Policy of the E. U. a box of 100 miles was created on the Azorean EEZ where almost only the Azorean fleets are permitted to fishing deep-sea species (Reg EC 1954/2003). TAC´s for deep-water sharks were implemented for ICES areas V. VI, VII, VIII, IX, X and XII.

WGEF considers that the elasmobranch fauna of Mid-Atlantic Ridge in Sub-areas X and XII is poorly understood. The species of demersal elasmobranchs are probably little exploited in comparison to continental Europe. The eco-region is considered to be a sensitive area. Consequently, commercial fisheries taking elasmobranchs in this area should not be allowed to proceed unless studies are conducted that can demonstrate what sustainable exploitation levels should be. The shallower waters of the Azores are well separated from the continental shelf waters of mainland Europe, and so shallow-water demersal species may form isolated populations.

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Table 15.1 Total landings (t) of Rajidae in area X 1980 1981 1982 1983 1984 1985 1986 1987 1988 1989 1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 Azores 86 74 46 44 38 25 27 37 48 29 35 52 43 32 55 62 71 99 117 103 83 68 70 89 72 France ...... 1 . . . . n.s. . 2 Spain ...... 24 29 Total 86 74 46 44 38 25 27 37 48 29 35 52 43 32 56 62 71 99 117 103 107 99 70 89

Table 15.2 Total landings (t) area XII Country Species 2001 2002 2003 2004 UK Rays and skates 1.1 0.5 5.9 0.8 UK Sharks - 6.7 - - Total 1 7 6 -

Table 15.3 Total landings (t) area XIV Country Species 2001 2002 2003 2004 UK Rays and skates 0.3 0.4 - - Total 0.3 0.4 - -

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Table 15.2. Length-weight relationship for Raja clavata estimated for the Azores area from the longline bottom survey data.

Length (cm) Weight (g) Regression parameters Species n min. max. min. max. a b r2 Raja clavata 404 37 89 270 5110 0.0058 3.0216 0.9301

140 120 100 80 60

Landings (mt) 40 20 0 1969 1974 1979 1984 1989 1994 1999 2004 Year

Azores France Spain

Figure 15.1. Historical landings of Rays from ICES area X.

15 RPN

0 1994 1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005 Year

Figure 15.2. Annual Relative Population Numbers of Raja clavata from the Azorean spring bottom longline survey (Azores ICES area X). 180 | ICES WGEF Report 2005

8.0 7.0 6.0 5.0 4.0 3.0 Mean RPN Mean 2.0 1.0 0.0 0-50 51-100 101-150 151-200 201-250 251-300 301-350 351-400 401-450 451-500 501-550 551-600

Stratum

Figure 15.3. Mean (1995-2004) Relative Population Numbers (RPN) of Raja clavata by strata, from the Azorean spring bottom long line survey for ICES area X.

Raja clavata (Azores - ICES X)

1.2

1.0

0.8

0.6

Mean RPN Mean 0.4

0.2

0.0 30 35 40 45 50 55 60 65 70 75 80 85 90 95 Length (TL cm)

Figure 15.4. Length composition of Raja clavata from the Azorean bottom longline survey. ICES WGEF Report 2005 | 181

Deania calceus (Azores - ICES X)

7.0 6.0 5.0 4.0 3.0

Mean RPN Mean 2.0 1.0 0.0 61 66 71 76 81 86 91 96 101 106 111 Length (TL cm)

Deania profundorum (Azores - ICES X)

4.0 3.5 3.0 2.5 2.0 1.5 Mean RPN Mean 1.0 0.5 0.0 36 41 46 51 56 61 66 71 76 81 86 91 96 101 Length (TL cm)

Figure 15.5. Length distribution of Deania calceus and D. profundorum from the Azorean Spring bottom longline survey for the period 1995–2004. 182 | ICES WGEF Report 2005

Etmopterus pusilus (Azores - ICES X)

8.0 7.0 6.0 5.0 4.0 3.0 Mean RPN Mean 2.0 1.0 0.0 18 20 22 24 26 28 30 32 34 36 38 40 42 44 46 48 Length (TL cm)

Etmopterus spinax (Azores - ICES X)

5 4 4 3 3 2

Mean RPN Mean 2 1 1 0 18 20 22 24 26 28 30 32 34 36 38 40 42 44 46 48 50 52 Length (TL cm)

Figure 15.6. Length distribution of Etmopteru pusillus and E. spinax from the Azorean Spring bottom longline survey for the period 1995–2004.

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16 Other pelagic species from the northeast Atlantic (ICES Subareas I–XIV)

This chapter includes information about two pelagic species with reported landings from ICES areas (I–XIV) - Blue shark (Prionace glauca) and Shortfin mako (Isurus oxyrinchus). Landings data on Thresher sharks (Alopias spp.) and pelagic generic landing categories are also presented. Due to the fact that most pelagic shark catches may be reported under generic landings categories, it is also presented landings data on Various sharks NEI and Cartilaginous fishes NEI categories.

16.1 Advice and management applicable

ACFM has never provided advice for these stocks.

The DELASS project and the ICCAT pelagic shark assessment working group (SCRS, 2004) considers one stock of blue sharks in the north Atlantic. Thus the ICES area is only part of the stock.

Last year, ICCAT conducted some assessments on Blue shark and Shortfin mako. Results of the assessments of Blue shark and Shortfin mako are presented in SCRS (2004). Thresher and shortfin mako sharks are caught in fisheries for tuna and swordfish. These are highly valuable species, and are likely to be retained. No new information was available on these species. Blue shark are low value and are often discarded in tuna and swordfish fisheries. Regarding Blue shark, North Atlantic blue shark population appear to have the current biomass above the biomass at MSY. Nevertheless, the results are highly conditional to assumptions made. Those assumptions include estimates of historical shark catch as described, the relationship between catch rates and abundance, the initial conditions of the stock in 1971 and various life-history parameters. In what concerns North Atlantic Shortfin mako, it is likely that it has historically experienced some level of stock depletion, but the ICCAT group cannot rule out the possibility of the current stock being below biomass at MSY in the North Atlantic as trends in the CPUE analysed suggests depletions of fifty percent or more could have occurred.

Due to limitations on the quantity and quality of the information available for the stock assessment of these two pelagic shark species the assessment studies conducted were considered to be very preliminary in nature.

No management recommendations were made by ICCAT regarding blue and mako sharks.

16.2 The fishery

The blue shark is probably the most abundant pelagic shark in offshore waters worldwide. In the North Atlantic, blue sharks are caught by several fisheries from diverse countries, however little has been done so far to assess the impact of these potentially large removals of individuals from the population. Although there are no large-scale directed fisheries for this species, it is a major by-catch in many fisheries for tunas and billfishes where it can comprise up to 70% of the total catches (ICES, 2004). Updated descriptions of fisheries taking blue shark are presented in SCRS (2004). In addition, a detailed description of the Basque fishery was presented in a Working Document by Diez et al. (2004) to WGEF 2004. In this WD it is referred that Blue shark is a traditional and rather low by-catch of many Basque (Spanish) fleets operating in the Bay of Biscay (ICES Divisions VIIIa,b,c,d).

Regarding Shortfin mako and thresher sharks, there is also no known directed fishery for these species. It is highly probable that these species are caught too as by-catch by tunas and billfishes fisheries operating in the North Atlantic. No new information on pelagic fisheries description was made available to WGEF.

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16.3 Biological composition of the landings

Blue shark in the Basque country. In a study conducted in the period 1998–2002, Guzman et al. (2004) have verified that most of the blue shark catches were composed by specimens with a size (Fork length) between 100 cm and 160 cm. In accordance with the maturity categories established by Pratt (1979) and Castro and Mejuto (1995), the blue shark population landed by the fleet operating in the Bay of Biscay is composed mostly of juvenile fish.

16.4 Catch data

Landings from some European countries on pelagic elasmobranch species have been provided to WGEF 2005. This is the case of Denmark, Spain (Basque country), Portugal (mainland) and Portugal (Azores). The majority of landings data presented for the categories, Sharks, rays, skates, etc. NEI, Various sharks NEI and Cartilaginous fishes NEI were retrieved from the FishStat plus database: ICES statistical landings 1973–2003 and FAO capture production data 1950–2003. Regarding Thresher sharks, only the data from national official landings sources provided by each country is presented.

Generic landing categories

In Figure 16.4.1 are presented landings statistical data of Sharks, rays, skates, etc. NEI from the Northeast Atlantic (ICES area) by country from 1978 to 2003. It can be seen that non- European countries have been capturing elasmobranch species in the ICES area. In the last years, the most important in terms of catches were Uruguay and Japan. The majority of these elasmobranch species may correspond to pelagic sharks caught by tuna fisheries. The methodology described in Figueiredo et al. (2005) to obtain a priori information on the most probable species being declared under generic landings categories was applied to data from non-European countries to find correlations between elasmobranch species landings and Tuna species landings. However, the low variability of the records by year on elasmobranchs species (only the generic landings category Sharks, rays, skates, etc. NEI is reported) prevented their successful application.

In Figures 16.4.2 and 16.4.3 are presented landings on Various sharks NEI category in the ICES area by country from two different time periods and sources. It is clear from the both Figures that the landings on this generic category have largely increased since 1981. Spain has been the major contributor to these landing values. Ireland has started to report landings only recently. These landings are likely to be composed mainly of pelagic sharks but may also include deep-water sharks.

In Figure 16.4.3 is presented landings statistics on Cartilaginous fishes NEI category in the ICES area by country from 1973 to 2003. During the first years of this period, France accounted for the majority of the landings reported reaching to nearly 14 000 tonnes in 1976. However, no more landings on this category have been reported by France since the early 1980’s. Spain has dominated the landings reported on this category since the beginning of the 1990’s. These landings may be composed mainly by pelagic shark species.

Pelagic shark landings tables

The best estimates of landings by the WGEF are presented for Blue shark (Table 16.4.1), Shortfin mako (Table 16.4.2) and Thresher sharks (Table 16.4.3). Some of the data presented in the tables were compiled from FishStat Plus database for 1973–2003 (Figures in grey).

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2500

2000

1500

Tonnes 1000

500

0 1978 1979 1980 1981 1982 1983 1984 1985 1986 1987 1988 1989 1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 2003 Year Faeroe Islands France Japan Korea, Republic of Latvia Poland Portugal Russian Federation Sweden Taiwan Province of China Un. Sov. Soc. Rep. Uruguay

Figure 16.4.1 – Total landings of Sharks, rays, skates, etc. nei category in the ICES area for the period 1978–2003. Source: FAO capture production data 1950–2003.

40000

30000

20000 Tonnes

10000

0 1950 1954 1958 1962 1966 1970 1974 1978 1982 1986 1990 1994 1998 2002 Year

Belgium Denmark Estonia Germany Ireland Netherlands Norway Spain United Kingdom

Figure 16.4.2 – Total landings of Various sharks NEI category in the ICES area for the period 1950–2003. Source: FAO capture production data 1950–2003.

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40000

30000

20000 Tonnes

10000

0 1973 1975 1977 1979 1981 1983 1985 1987 1989 1991 1993 1995 1997 1999 2001 2003 Year

Belgium Denmark Estonia Germany Ireland Netherlands Norway Poland Portugal Spain Sweden UK USRR

Figure 16.4.3. – Total landings of Various sharks NEI category in the ICES area for the period 1973–2003. Source: ICES statistical landings 1973–2004.

40000

30000

20000 Tonnes

10000

0 1973 1975 1977 1979 1981 1983 1985 1987 1989 1991 1993 1995 1997 1999 2001 2003 Year

Faeroe Islands France Poland Portugal Spain Sweden UK USSR

Figure 16.4.4 – Total landings of Cartilaginous fishes NEI category in the ICES area for the period 1973–2003. Source: ICES statistical landings 1973–2004.

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Table 16.4.1 - Total landings of Blue Shark Prionace glauca by country from the ICES area

1978 1979 1980 1981 1982 1983 1984 1985 1986 1987 1988 1989 1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 Denmark + + + + + + + + + + + 2 2 1 1 + 1 2 3 1 1 + 2 + 13 6 1 France 4 12 . . 9 8 14 39 50 67 91 79 130 187 276 322 350 266 278 213 163 230 395 207 112 132 n.a. Ireland ...... 67 22 66 11 3 + Spain (Basque country) ...... 673 439 383 550 442 457 482 367 390 Portugal + + + + + + + + + + + + + + + + + + + + 886 1133 1006 1209 2170 323 UK (Channel Is.) + + + + + + + + + + + . 1 . . . + . + . 1 . 12 9 5 4 n.a. UK (E&W) + + + + + + + + + + + . 1 . . . + . + . 1 . 12 9 5 4 n.a. UK (E&W, NI) + + + + + + + + + + + . 1 . . . + . + . 1 . 12 9 5 4 n.a. UK (Guernsey) + + + + + + + + + + + . 1 . . . + . + . 1 . 12 9 5 4 n.a. UK (Is. Man) + + + + + + + + + + + . 1 . . . + . + . 1 . 12 9 5 4 n.a. UK (Jersey) + + + + + + + + + + + . 1 . . . + . + . 1 . 12 9 5 4 n.a. UK (NI) + + + + + + + + + + + . 1 . . . + . + . 1 . 12 9 5 4 n.a. UK (Scotland) + + + + + + + + + + + . 1 . . . + . + . 1 . 12 9 5 4 n.a. Total 4 12 + + 9 8 14 39 50 67 91 81 140 188 277 322 351 268 954 653 555 1733 2090 1808 1867 2710 714

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Table 16.4.2 - Shortfin mako (Isurus oxyrinchus) - Total landings by country for the ICES area.

1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 Portugal (mainland) 70 44 44 37 43 68 100 52 49 37 44 40 108 74 Portugal (Azores) 5 14 7 6 8 12 11 4 6 9 15 12 11 15 19 UK (E&W, NI) 3 4 5 2 1 1 n.a. Total 5 84 50 50 44 55 79 104 62 63 58 58 52 124 93

Table 16.4.3 - Landings on Thresher sharks (Alopias spp.) by country and ICES sub-area

2001 2002 2003 2004 Denmark IV . . + . Ireland VII . . + +

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17 Elasmobranch NEI landings in ICES area (I–XIV)

This chapter presents most of the work conducted on the analysis of elasmobranch generic NEI landings categories that is included in the Working Document presented to WGEF 2005 entitled ‘An overview of elasmobranch nei landings from the north-east Atlantic in the period 1973–2003’ (Figueiredo et al., 2005).

17.1 Outline of the work

The variation of landing statistics on elasmobranch NEI (Not Elsewhere Identified) categories from ICES area are analysed in detail by year, country, ICES sub-area and division. The time range investigated comprehended thirty years, from 1973 to 2003. To help understanding trends displayed by the different NEI categories, landing statistics reported to other teleost and elasmobranch species were comparatively investigated. Particularly emphasis was put on the analysis of Various Sharks NEI, Cartilaginous Fishes NEI and the Dogfish sharks NEI, all here grouped into the UNKNWON GROUP (see the results and discussion chapter for more details) which present tremendous amounts of landings and that unfortunately are still increasing in recent years. The work presented in this document addresses several issues which are outlined below:

Identification of existent elasmobranch fishes NEI categories. NEI categories were assembled in distinct GROUPS defined according to depth distribution and/or distance to coast. In addition, NEI landings categories were aggregated by country.

Elasmobranch species identified in the landings. The landings of individual species were split into GROUPS following the procedure in 2.1 and evaluated by country. The relative importance of individual species landings categories in the total elasmobranchs landings by country was also evaluated.

Temporal variation of elasmobranchs NEI landings statistics. The temporal evolution of the total NEI landings was described by ICES sub-area and by country. In the case of sub-areas VI, VII and VIII, the description of some NEI landings categories also included the correspondent ICES divisions. The relative importance of each NEI landings category along the period considered was analysed. Categories landings patterns were identified along the years by country, sub-area and division, putting into evidence shifts intra- and inter-categories.

Analysis of landing estimates correlation discriminated by country, ICES Division and taxa subset. This analysis aimed to investigated, for each country and ICES division, the taxa subset more correlated with the NEI categories. It was expected that with this procedure an insight of the fisheries that major contributed for the landings statistics figures of the NEI categories is obtained.

Linkage of UNKNOWN landing estimates from different countries and Division to one of the following GROUPS: PELAGIC; DEMERSAL AND DEEP-SEA through a statistical clustering method, using landing information from TAXA SUBSETS. The huge values of NEI categories for which there is no information whatsoever about species diversity - UNKNOWN - creates serious problems. The proposed procedure was strongly based on the overall previous exploratory results and was essayed in order to circumvent this deficiency

17.2 Data source The analyses described in the course of this document were conducted by using FAO landings statistical data from area 27 of the period 1973–2003. ICES catch statistics 1973–2003 FishStatPlus.

In Annex I of Figueiredo et al. (2005) is presented a list of the elasmobranch species/ NEI categories analysed throughout the paper, which includes FAO codes, scientific names and GROUPS of species.

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17.3 Results and discussion

17.3.1 Identification of existent elasmobranch fishes NEI categories At the North-eastern Atlantic area there is a special concern about the existence of several groups of NEI categories in FAO landings statistics. In some NEI categories, it is possible to have an idea about the bathymetric range of the species included and associate the respective NEI category reported by a particular European country with the fisheries that the country is developing in an ICES sub-area. Based on this information seven GROUPS of NEI categories were established, being five of them directly related to the bathymetric range and/or distance to the coast (Table 17.1). These are by alphabetic order: CHIMAERIDAE, COASTAL, DEEP-SEA, DEMERSAL, PELAGIC, SKATES-and-RAYS and UNKNOWN.

Table 17.1 - List of categories NEI with reference to the GROUP of species, FAO code, Common Name and Scientific name.

FAO Common Scientific Group Code name name Chimaeridae HYD Ratfishes nei Hydrolagus spp Coastal GUZ Guitarfishes nei Rhinobatos spp Coastal TRK Houndsharks,smoothhounds nei Triakidae Coastal SDV Smooth-hounds nei Mustelus spp Deep-sea GAU Crest-tail catsharks nei Galeus spp Deep-sea SHL Lanternsharks nei Etmopterus spp

Demersal SCL Catsharks, nursehounds nei Scyliorhinus spp Demersal ASK Angelsharks, sand devils nei Squatinidae Demersal SYX Catsharks, etc. nei Scyliorhinidae Demersal DGH Dogfishes and hounds nei Squalidae, Scyliorhinidae Demersal DGZ Dogfishes nei Squalus spp Pelagic SPN Hammerhead sharks nei Sphyrna spp Pelagic RSK Requiem sharks nei Carcharhinidae Skates Rays TOD Electric rays nei Torpedinidae Skates Rays SKA Raja rays nei Raja spp Skates Rays RAJ Rays and skates nei Rajidae Skates Rays SRX Rays, stingrays, mantas nei Rajiformes Skates Rays STI Stingrays nei Dasyatis spp Skates Rays STT Stingrays, butterfly rays nei Dasyatidae Unknown CAR Cartilaginous fishes nei Chondrichthyes Unknown DGX Dogfish sharks nei Squalidae Unknown SKH Various sharks nei Selachimorpha(Pleurotremata)

In most European countries the landings assigned to NEI categories are high (Tab. 2), particularly those who belong to the UNKNOWN group. SKATES-and-RAYS (72%) and COASTAL (67%) register the highest levels of proportion unidentified vs identified species, while DEEP-SEA (9.9%) and PELAGIC (0.2%) present extremely low levels (Table 17.3). There is an extremely low discrimination of species included in PELAGIC and DEEP-SEA categories (Table 17.4). It is strongly suspected that most of landings from these categories are most grouped and assigned to the generic categories from UNKNOWN group.

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SKATES-and-RAYS comprise a mixture of species with different bathymetric ranges. Nonetheless, up to now, it has commonly presented a predominance of coastal species. The UNKNOWN group is a broad generic assemblage to which there is no idea about bathymetric preference of the species included in it and may vary in the species composition from country to country or even within fisheries from the same country in different ICES sub-areas.

17.3.2 Elasmobranch species identified in the landings

Although there has been a large quantity of landings reported as NEI, some individual elasmobranch species landings have occurred. However, the average annual number of species reported by country and the total annual number of species reported for the ICES area have only recently increased (Figure 17.1).

10 60 9 8 50 7 40 6 5 30

country 4 3 20 2 10

Average no. of species / 1 species of number Total 0 0 1973 1975 1977 1979 1981 1983 1985 1987 1989 1991 1993 1995 1997 1999 2001 2003 Year

Total number of species Average no. of species by country

Figure 17.1 – Average annual number of elasmobranch species reported in landings by country and total annual number of elasmobranch species reported by year for the ICES area in the period 1973–2002.

Next the most important elasmobranch species that have landings by country reported in the period 1973– 2003 are described by GROUP of species.

For the PELAGIC Group there are landing estimates discriminated for eight different species. Porbeagle is by far the most landed species followed by Blue shark, Basking shark (which most of the landings are derived from Norway) and Tope shark (Table 17.3).

For the DEEP-SEA group, Gulper shark, Kitefin shark, Portuguese dogfish, Leaf-scale gulper shark and Greenland shark are the most important species for which landing estimates are available (Table 17.3). In the DEMERSAL group, Picked dogfish presents the highest landing estimates followed by Small-spotted catshark. Angel shark landing estimates are mainly derived from France (Table 17.3).

In the COASTAL group there are very few landing estimates reported by species. In France there is only information for Nursehound. UK presents important landing estimates of this species and only a reduced value for Smooth-hound. Although in Portugal the figures of landings estimates are low (less 50 ton for the all period) three species are reported: Nursehound, Smooth-hound and Starry smooth-hound (Table 17.3).

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In the SKATES-and-RAYS group, the species with the highest landings are derived from Blue skate, Thornback ray, Shagreen ray, Sandy ray, Spotted ray, Cuckoo ray, Longnosed skate and Starry ray (Table 17.3).

In the CHIMAERIDAE Group, Rabbit fish is by far the most important species in terms of landing estimates, which are mainly derived from Iceland (representing nearly 75%).

More detailed descriptions of the landing estimates, by subarea from all the species groups are included in Annex II.

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Table 17.2 – Total landings of each NEI category by GROUP of species and country in the period 1973–2003.

GROUP PelagicCoastal Skates Rays FAO Code RSK SPN GUZ SDV TRK RAJ SKA SRX STI STT TOD Country Belgium 48356 Denmark 2465 Estonia 62 Faeroe Islands 6343 France 12772 575 200881 35 Germany 2570 Iceland 5484 Ireland 2 26768 40485 126 Lithuania 1289 Netherlands 7542 Norway 28604 Poland 149 Portugal 266 32 6 238 468 51379 13 110 Spain 84188 Sweden 225 UK 1 638 242004

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Table 17.2 - (cont.)

GROUP Demersal Deep-seaChimaeridae Unknown FAO Code ASK DGH DGZ SCL SYX GAU SHL HYD CAR DGX SKH Country Belgium 14088 258 Denmark 5725 83 Estonia 57 Faeroe Islands 78 2864 France 258 10321 2532 66563 42102 Germany 2438 2604 Iceland Ireland 6072 297 4 5996 1307 Lithuania 4 76 Netherlands 3 Norway 499 41 92 Poland 3143115 Portugal 2 30233 3760 5428 23846 13189 Spain 34 99 44556 4324 194846 Sweden 6 97 1 UK 11930 104 46 1 408 3969 22952

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Table 17.3 - Total landings of each individual elasmobranch species by GROUP of species and country in the period 1973–2003.

GROUP Pelagic Coastal FAO Code ALV BSH BSK GAG POR SMA SPZ TIG SDS SMD SYT Country Belgium Denmark 35 25 3135 Estonia Faeroe Islands 447 France 410 3634 11 14791 12790 5174 Germany 33 Iceland 54 Ireland 168 5 30 Lithuania Netherlands 61 Norway 123176 2093 Poland Portugal 97 6404 12 69 19 1182 1 7 11 33 Spain 6113 Sweden 85 UK 32 1038 188 9 15 1496

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Table 17.3 – (cont.)

GROUP Demersal Chimaeridae FAO Code AGN DGS SYC CMO CYH RAT RCT RHC Country Belgium 12434 Denmark 28391 Estonia 3 Faeroe Islands 596 France 194 158669 140196 Germany 3011 Iceland 2042 858 5 Ireland 63776 1197 40 5 Lithuania Netherlands 3568 Norway 197264 160 Poland 18 Portugal 75 Spain 1215 6 Sweden 10555 UK 51 386652 2455 87 3 2

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Table 17.3 - (cont.)

GROUP Deep-sea FAO Code CFB CYO CYP CYY DCA ETX GSK GUP GUQ OXN OXY SBL SCK SHB SHO SOR Country

Belgium Denmark Estonia Faeroe Islands 719 1 France 627 1033 18 110 Germany 6 Iceland 6 7 1822 Ireland 1358 1 33 Lithuania 7 Netherlands Norway 13 56 1 Poland Portugal 19563 10 233 23 16116 23671 407 10 732 1 182 Spain 135 12GROUP 8 495 1 230 2 Skates Rays Sweden UKFAO Code EAG JAT JDP 5899 MYL 502 RFT RGL 3 RJB 23 RJC 5 RJE RJF RJG 638 RJH 1423 RJI RJK RJM RJN RJO 557 RJR RJU TOE TTR Country Belgium Denmark 130 Estonia Faeroe Islands France 96 39 4 8991 48767 24 1680 5616 22091 87389 4156 22 237 138 Germany Iceland 2032 219 10 14298 Ireland 9 1 5 1 1 1 Lithuania Netherlands Norway 220 2 Poland Portugal 40 15 17 50 18 183 Spain Sweden UK

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Table 17.4 – Total landings of identified elasmobranch species and NEI categories by GROUP of species and country in the period 1973–2003.

Skates Rays Deep-sea Demersal Chimaeridae Pelagic Coastal Unknown Country identified nei identified nei identified nei identified nei identified nei identified nei nei Belgium 48356 12434 1488 258 Denmark 13 2465 28391 3195 5808 Estonia 62 3 57 Faeroe Islands 6343 72 596 447 2942 France 17925 21491 1788 1321 29959 258 2532 31636 5174 12772 108665 Germany 257 6 311 33 5042 Iceland 16559 5484 1835 242 863 54 Ireland 18 67379 1392 4 64973 6369 45 23 2 7303 Lithuania 1289 7 4 76 Netherlands 7542 3568 61 3 Norway 222 2864 7 197264 499 16 41 125269 92 Poland 149 18 360 Portugal 323 5152 6948 75 33995 7784 298 51 712 42463 Spain 84188 883 99 1221 34 6113 243726 Sweden 225 1555 6 85 98 UK 242642 95 389158 128 92 1 1267 1511 1 27329

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17.3.3 Temporal variation of elasmobranchs NEI landing statistics 17.3.3.1 Total NEI landings

The landings of NEI categories have been increasing for the last thirty years in the ICES subareas (Figure 17.2). These are particularly evident during the period between 1990 and 2003. The total NEI landings have increased from about 5000 tons in 1990 to nearly 25 000 tons in 1995 and almost 40 000 tons in 1997.

Subareas IX and X accounted for the majority of the landings, showing values higher than 8000 tons/year (Figures 17.3, 17.4). Spain is the country which has contributed more to the figures from these sub-areas, having presented more than 80 000 tons in each sub-area for the period between 1990 and 2003 (Figures 17.5, 17.6).

The NEI landings from sub-area XII (Figure 17.7) started to increase during the beginning of the 90’s. Several countries have contributed with landings. Spain was the most important with landing values higher than 1 000 tons/year in the period 1997–2002, followed by United Kingdom and France (Figure 17.8).

Regarding sub-area VIII (Figure 17.9), Spain accounts for the majority of the landings from this sub-area with more than 90% of the total landings presented between 1990 and 2002 (Figure 17.10). The division which had more landings registered was VIIIc, followed by division VIIIb.

The majority of landings from sub-area VII in the period 1990–2003 (Figure 17.11), were presented by UK, closely followed by Spain, comprising a total of nearly 23 000 tons. France and Ireland presented total landings of about 5000 t each and Germany a total of 2218 t (Figure 17.12). The principal division with NEI landings was VIIj followed by VIIk.

45000

40000

35000 XII 30000 X 25000 IX

Tons 20000 VIII VII 15000 VI 10000

5000

0 1973 1975 1977 1979 1981 1983 1985 1987 1989 1991 1993 1995 1997 1999 2001 2003 Year

Figure 17.2 – Variation of NEI annual landings by ICES sub-area along the period 1973–2003 200 | ICES WGEF Report 2005

France and UK had the highest total landings from Subarea VI in the period 1990–2003 (Figure 17.13). France presented ca. 16 000 t and UK nearly 10 000 t (Figure 17.14). Ireland, Spain and Germany had also landings from this sub-area with totals higher than 1000 t. VIa was clearly the principal division of Subarea VI with landings on NEI categories.

16000

14000

12000

10000

8000 Tons 6000

4000

2000

0 1973 1976 1979 1982 1985 1988 1991 1994 1997 2000 2003 Year

Figure 17.3 – Variation of NEI annual landings in sub-area IX along the period 1973–2003.

16000 14000 12000 10000 8000 Tons 6000 4000 2000 0 1973 1976 1979 1982 1985 1988 1991 1994 1997 2000 2003 Year

Figure 17.4 – Variation of NEI annual landings in sub-area X along the period 1973–2003. ICES WGEF Report 2005 | 201

163

84432 12115

Portugal Spain UK

Figure 17.5 – European countries individual contribution (tonnes) to the total landings on NEI categories from sub-area IX in the period 1973–2003.

8211 81953

Faeroe Islands Portugal Spain Figure 17.6 – European countries individual contribution (tonnes) to the total landings on NEI categories from sub-area X in the period 1973–2003.

16000 14000

12000 10000 s 8000 Ton 6000 4000 2000 0 1973 1976 1979 1982 1985 1988 1991 1994 1997 2000 2003 Year

Figure 17.7 – Variation of NEI annual landings in Subarea XII along the period 1973–2003.

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681 156 12461 239

France Spain UK Other

Figure 17.8 – European countries individual contribution (tonnes) to the total landings on NEI categories from sub-area XII in the period 1973–2003.

16000

14000

12000

10000

8000 Tons 6000

4000

2000

0 1973 1975 1977 1979 1981 1983 1985 1987 1989 1991 1993 1995 1997 1999 2001 2003 Year

Figure 17.9 – Variation of NEI annual landings in sub-area VIII along the period 1973–2003.

119 12 30311 722 351

France Portugal Spain UK Other

Figure 17.10 – European countries individual contribution (tonnes) to the total landings on NEI categories from sub-area VIII in the period 1973–2003.

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16000

14000

12000

10000

8000 Tons 6000

4000

2000

0 1973 1976 1979 1982 1985 1988 1991 1994 1997 2000 2003 Year

Figure 17.11 – Variation of NEI annual landings in Subarea VII along the period 1973–2003.

12986

76 10346

5237

2218 5751 France Germany Ireland Spain UK Other

Figure 17.12 – European countries individual contribution (Tons) to the total landings on NEI categories from sub-area VII in the period 1973–2003. 204 | ICES WGEF Report 2005

16000

14000

12000

10000

8000 Tons 6000

4000

2000

0 1973 1976 1979 1982 1985 1988 1991 1994 1997 2000 2003 Year

Figure 17.13 – Variation of NEI annual landings in sub-area VI along the period 1973–2003.

1549 1084 1032

9896

16036 181

France Germany Ireland Spain UK Other

Figure 17.14 – European countries individual contribution (tonnes) to the total landings on NEI categories from Subarea VI in the period 1973–2003.

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17.3.3.2 Individual NEI categories landings from the UNKNOWN group

The temporal variation of each elasmobranchs NEI categories landings from the UNKNOWN group in the period 1973–2003 are described for each country, ICES subarea and division in Figueiredo et al. (2005).

17.3.4 Correlation analysis

The correlations between Wysd of the UN group with other Wysd of other species groups have increased along the periods considered. Below are presented for each period and country, the ICES divisions where positive correlations (σ > 0.70) were obtained between UN group and other species groups. Only the six principal countries with landings on NEI categories were analysed: France, Germany, Ireland, Portugal, Spain and UK. These correlation values (σ > 0.70) obtained for the different periods, countries and ICES divisions are presented in Table 17.5.

- 1st Period -

France. The landings of UN group showed positive correlation with landings of Anglerfishes and Ling groups in division VIIb+c suggesting that the captures included in the declared elasmobranch NEI categories were composed of demersal and/or deep-sea species. The correlation found in division IVa also suggests that the recorded landings that belong to the unknown group are composed of elasmobranch demersal species. In division ‘VIII not specified’, the UN group might have included captures of pelagic elasmobranchs since a positive correlation were found with the TU group.

Germany, Ireland and Portugal. No positive correlations (σ > 0.70) were found in any of the ICES divisions analysed.

Spain and UK. Both countries’ landings from the UN group exhibited positive correlation with the Ling group in division ‘IX not specified’ (Spain) and division VIIa (UK) suggesting the occurrence of captures of deep-sea elasmobranch species.

- 2nd Period -

France. It is probable that the landings of the UN group from division VIa may include pelagic elasmobranch species due to the positive correlation found with pelagic group landings.

Spain. In division ‘IX not specified’, Spanish landings of UN group showed positive correlation with the Skates and Rays group. So, it could be possible that the Various sharks NEI landings registered in the 2nd period included captures of deep-sea rajiform species.

Germany, Ireland, Portugal and UK. No positive correlations (σ > 0.70) were found in any of the ICES divisions analysed.

- 3rd Period -

France. The landings of the UN group presented positive correlations with landings of demersal and deep-sea species groups in three divisions, namely, VIIc, VIIj and VIIk. In division VIIk there was also found a positive correlation with the pelagic group landings, however, the correlation coefficient value is lower (0.86) than the ones obtained for the two previous groups. Therefore, it might be possible that the majority of the NEI landings recorded in VIIk correspond to deep-sea and demersal species.

Germany. The correlations found in divisions VIa and VIb with the Ling group suggest that UN group landings are composed by deep-sea species.

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Portugal. The positive correlations found in sub-area X are not conclusive about which species may have been landed within the UN group. Nevertheless, the highest correlation (0,96) found was with the Ling group. The positive correlation found in division ‘IX not specified’ with the BS group may be related with the black scabbardfish fishery that captures deep-sea sharks as by-catch. In division VIIIc the landings of the UN group might have included demersal species.

UK. Landings of the UN group presented positive correlations with demersal and deep-sea groups in divisions VIIj and VIIk. It also presented positive correlation with Skates and Rays group in divisions VIIj and VIIc.

- 4th Period -

France. The landings of the UN group presented positive correlations with landings of BS group in division VIIj. This suggests that the species landed as NEI were probably deep-sea elasmobranchs.

Ireland. This country began to present positive correlations of UN group landings with other species groups in the fourth period. This occurred in division VIIb for LI and SR groups, having each group a correlation higher than 90%. Division VIIj showed also correlation for two species groups SR (0.80) and TU (0.82). This could mean that more shallower or pelagic species were captured within the UN group, however, the relation is not clear. As already seen in chapter 4.3.2 catches of deep-sea sharks such as Portuguese dogfish seemed to occur mainly in divisions VIIc and VIIk.

Portugal. The positive correlation found in division X with TU group clearly suggests that elasmobranch species landed as NEI corresponded to pelagic species.

Spain. The results found for this country, suggests that the UN group landings in divisions IXa and XII are mainly comprised by demersal and deep-sea species. It was also estimated a positive correlation with SR groups in division IXa, which might be related with a Spanish fishery for rays operating in Iberian occidental waters.

UK. A strong correlation (0.93) was estimated between landings of the UN group and landings of the BS group from the division VIa, suggesting that elasmobranchs declared as NEI are most probably deep-sea sharks. The correlations found in division VIb are not conclusive about which species might be included in the NEI landings category, as similar correlation values were found for the DE and SR groups.

Germany. No positive correlations (σ > 0.70) were found in any of the ICES divisions analysed.

- 5th Period -

France. The landings of the UN group presented positive correlations with landings of AN group in division VIa and with DE group in divisions VIb and VIIj. This suggests that the elasmobranchs landed as NEI from these divisions might be demersal or deep-sea species.

Ireland. The correlations results obtained for division VIa between UN group and BS and LI groups clearly suggests that the NEI landings are composed of deep-sea elasmobranch species.

Portugal. In division ‘IX not specified’ the majority of correlations obtained are with demersal and deep-sea species groups, however, there was also found correlation with TU group. In division X, the results clearly suggests that elasmobranch NEI landings comprise pelagic species.

Spain. In the 5th period, Spain has presented positive correlations in many of the divisions analysed. Elasmobranch NEI landings from divisions VIIIa+VIIIb, VIIIc+VIIId seem to be

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comprised of deep-sea species, while divisions IXb and X clearly seem to be composed by pelagic species. Division XII presented correlations between UN group and demersal and deep-sea groups of species. In division IXa two positive correlations were obtained, one with PE group and other with LI group, however this last group showed higher correlation (0.98).

UK. The correlations results obtained for division VIb and VIIc between UN group and BS and DS groups clearly suggests that the NEI landings are composed of deep-sea elasmobranch species.

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Table 17.5 – Pearson correlation values obtained between landings of the UNKNOWN group and landings of different taxa subsets, by period, country and ICES division. No correlations were found with the Taxa CH, CO and RG.

Taxa sub-sets Country ICES Division AN BS DE DS LI PE SR TU IVa ------0,924 ------France VIIIb+c 0,918 ------0,719 ------VIII n. sp. ------0,872 Spain IX n. sp. ------0,980 ------U.K. VIIa ------0,790 ------France VIa ------0,981 ------Spain IX n. sp. ------0,780 ---

VIIc 0,999 0,998 ------France VIIj --- 0,999 --- 0,999 ------VIIk 0,794 0,982 ------0,960 0,963 ------VIa ------0,972 ------Germany VIb ------0,983 ------VIIIc ------0,975 ------Portugal IX n. sp. --- 0,771 ------X --- 0,797 ------0,956 --- 0,772 --- VIIc ------0,999 --- U.K. VIIj ------0,995 ------0,798 --- VIIk 0,965 ------

France VIIj 0,739 ------VIIb ------0,981 --- 0,938 --- Ireland VIIj ------0,803 0,820 IXa 0,738 ------0,744 --- 0,841 --- Spain XII --- 0,942 ------0,991 ------VIa --- 0,937 ------U.K. VIb ------0,708 ------0,883 ---

VIa 0,978 ------France VIb ------0,818 ------VIIj ------0,773 ------Germany VIb 0,900 ------Ireland VIa --- 0,716 ------0,725 ------IX n. sp. 0,808 0,945 0,923 ------0,716 Portugal X ------0,998 VIIh ------0,999 --- VIIk ------0,878 --- VIIIa+VIIIb 0,980 ------VIIIc+VIIId ------0,977 ------Spain IXa ------0,982 0,806 ------IXb ------0,999 ------X ------0,997 XII --- 0,865 ------0,975 ------VIb --- 0,983 ------UK VIIc ------0,990 ------

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17.3.5 Cluster analysis results and discussion

The approach followed to the last period (5th period from 2000 to 2002) seemed to be quite promising for a future to assignment of unspecified landings of elasmobranchs to different groups, which were defined according to different bathymetric ranges. This procedure takes the advantage of without any previous knowledge of auxiliary information group the data into clusters. The incorporation of the auxiliary information is done afterwards, during the interpretation of the results in which the consistency of the inclusion of the Unknown groups to particular cluster can be thus evaluated. In the present approach, it was observed that in the majority of the clustering results the group SR commonly created noisy results and because of that SR it was commonly excluded Such behaviour is probably related to the mixed bathymetric range of elements present in this group.

Germany. Cluster results for Unknown groups from Germany suggest that those from VIb and VIIj may be partially constituted by deep-water species while that from VIIk is more related to the Demersal category.

Ireland. Cluster results for Unknown groups from Ireland suggest that are most probably associated to Deep-sea category, particularly the one from Division VIIk.

Spain. Cluster results for Unknown groups from the first subset of Spain suggest they are most probably associated to Demersal categories. In the second subset the Unknown groups from Division VIIIa+VIIIb seem to be associated to Demersal categories and those from Divisions IXb, IXa, X seem to be associated with Pelagic category. The two Unknowns groups from VIIIe and VIIc+VIId may be partially related to Pelagic and Deep-sea categories.

UK. Cluster results for Unknown groups from the first subset of UK suggest that that from VIIk, VIIc and VIb are most probably associated to Deep-sea category and that from Division XII may be partially related to Demersal and Deep-sea categories. In the second subset the Unknown group from division VIIj seem to be related to a Deep-sea category and the one from VIa to a mixture of both Demersal and Deep-sea categories.

Portugal. Cluster results for Unknown groups from Division IX of Portugal suggest that it is most probably associated to Demersal category, while the one from Division X seems to be very heterogeneous probably partially related to Pelagic and Deep-sea categories.

France. In the first subset from France, the Unknown groups from VIIj suggest that it is most probably associated to Demersal while those from VIa and VIIIa+VIIIb are difficult to make a conclusion since all the three categories are present (Demersal, Pelagic and Deep-sea). In the second subset the Unknown group from Division VIIc seems to be related to a Deep-sea category and the one from Divisions VIIk to a mixture of both Demersal and Deep-sea categories. The unknown group from Division VIb seems to be associated with a Demersal category while the Unknown group from XII is difficult to establish any conclusion since all the three categories are present (Demersal, Pelagic and Deep-sea).

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Hareide N-.R., and Garnes, G. 2000. Misreporting – Results from Norwegian investigations on coastal gillnet fisheries. Working Document. Hareide, N. R., and Garnes, G. 2001. The distribution and Abundance of Deep Water Fish along the Mid-Atlantic Ridge from 430 N to 610 N. Fisheries Research, 51: 297–310. Hareide, NR, Clarke, M., Connolly, P., Rihan, D., Tyndall, P., Mulligan, M., Misund, R., Furevik, D., Humborstad, O., McMullen, P., Hoydal, K., Blasdale, T and Newton, A. 2004. A preliminary investigation on shelf edge and deep waterfixed net fisheries to the West and North of Great Britain and Ireland, around Rockall, and Hatton bank. DEEPNET Final Report. Hareide, N-R., Garnes, G., Wammer, A.W., Berg, V., Moe, E. 1999. ”Forsøksfiske etter makrellstørje (Thunnus thynnus) august–september 1998.” Møreforskning Ålesund Rapport, Å9910. Heessen, H.J.L. (Ed.) 2003. Development of elasmobranch assessements DELASS. Final report of DG Fish Study Contract 99/055, 603 p. Henderson, A.C. and Casey, A. 2001. Reproduction and growth in the lesser-spotted dogfish Scyliorhinus canicula (Elasmobranchii: Scyliorhinidae), from the west coast of Ireland. Cahiers de Biologie Marine, 42(4): 397–405 Henderson, A.C., Flannery, K., Dunne, J. 2001. Growth and reproduction in spiny dogfish Squalus acanthias L. (Elasmobranchii: Squalidae), from the west coast of Ireland. Sarsia, 87(5): 350–261. Henderson, A.C., Flannery, K, and Dunne, J. 2002. J. Nat. Hist., 36(16): 1995–2004. Hilborn, R. and Walters, C.J. 1992. Quantitative fisheries stock assessment: choice, dynamics, and uncertainty. Chapman & Hall, New York, NY. 570 pp. Holden, M.J. 1968. The rational exploitation of the Scottish-Norwegian stock of spurdogs (Squalus acanthias L.). Fishery Investigations, Series II, 25(8), MAFF, London, 27pp. Holden, M.J. 1974. Problems in the rational exploitation of elasmobranch populations and some suggested solutions. In Sea Fisheries Research (F.R.Harden Jones, ed.). Elek: London, 117-137. Holden, M.J. and Meadows, P.S. 1962. The structure of the spine of the spurdog fish (Squalus acanthias L.) and its use for age determination. Journal of the Marine Biological Association of the United Kingdom, 42: 179–197. Holden, M.J. and Meadows, P.S. 1964. The fecundity of the spurdog (Squalus acanthias L.). Journal du Conseil International Pour l'Exploration de la Mer, 28: 418–424. Holden, S., Kirkwood, G.P., and Bravington, M.. 1995. C.E.D.A.: catch and effort data analysis, version 2.01. Marine Resources Assessment Group Ltd., 18 Queen Street, London, WJ1 5PN, UK. ICES. 1998. Report on the Study Group on the Biology and Assessment of Deep Sea Fisheries Resources. ICES CM 1998/ACFM:12. ICES. 2000. Report of the Study Group on the Biology and Assessment of Deep-Sea Fisheries Resources, ICES Headquarters, 4–10 February 2000. ICES CM 2000/ACFM:8. 206 pp. ICES. 2002a. Report of the Study Group of the Elasmobranch Fishes (SGEF). ICES CM 2002/G:08. ICES. 2002b. Working Group on the Biology and Assessment of Deep-Sea Fisheries Resources (WGDEEP), Horta, The Azores, Portugal, 4–10 April 2002. ICES CM 2002/ACFM:16. 244 pp. ICES. 2003. Report of the Study Group of the Elasmobranch Fishes (SGEF). ICES CM 2003/G:09

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Machado, P.B., Serrano Gordo, L., and Figueiredo, I. 2004. Skate and ray species composition in mainland Portugal from the commercial landings. Aquatic Living Resources, 17(2): 231–234. Mejuto, J. 1985. Associated catches of sharks, Prionace glauca, Isurus oxyrinchus and Lamna nasus, with NW and N Spanish swordfish fishery in 1984. ICES C.M. 1985/H:42: 16pp. Muñoz-Chápuli, R., 1984. Ethologie de la reproduction chez quelques requins de l'Alantique nord-est. Cybium, 8(3): 1–14. Myklevoll S. 1968 Basking shark fishery. Commer. Fish. Rev. 30:59–63. Pella, J.J. and Tomlinson, P.K. 1969. A generalized stock production model. Bulletin of the Inter-American Tropical Tuna Commission, 13(3): 419–496. Pérez, N., Pereda, P., Uriarte, A., Trujillo, V., Olaso, I., and Lens, S.. 1996. Descartes de la flota española en el área del ICES. Datos y Resúmenes. Inst. Esp. de Oceanogr., 2: 142 pp Pinho, M. R. 2005. Elasmobranchs of the Azores. WGEF 2005 WD Pratt, H.L. 1979. Reproduction in the blue shark, Prionace glauca. Fishery Bulletin, 77(2): 445–470. Pried, I. G., F. Rainer, Bailey, D. M., Bergstad, O. A., Collins, M. A., Dyb, J. E., Henriques, C., Jones, E. G. and King, N. 2005. The absence of sharks from abyssal regions of the world`s oceans. Patterns and processes of the ecosystems of northen Mid-Atlantic (MAR- ECO). Field phase workshop and steering group meeting, IPIMAR, Lisbon, Portugal 2-5 June, 2005. Punt, A. E. and Walker, T. I. 1998. Stock assessment and risk analysis for the school shark (Galeorhinus galeus) off southern Australia. Marine and Freshwater Research 48, 719– 731. Punt, A. E., Pribac, F., Walker T. I., and Taylor, B.L. 2001. Population modelling and harvest strategy evaluation for school and gummy shark, Report of FRDC 99/102. CSIRO Marine Research, Hobart. Rae, B.B. 1962. Scottish Fisheries Bulletin. Redeke, H.C., 1935. De Noordzeevisserij. (The North Sea fishery) De Arbeiderspers, Amsterdam, 104 pp. Revill, A., Dulvy, N.K., and Holst, R. 2005. The survival of discarded lesser-spotted dogfish (Scyliorhinus canicula) in the Western English Channel beam trawl fishery. Fisheries Research, 71, 121–124. Rijnsdorp, A.D., van Leeuwen, P.I., Daan, N., and Essen, H.J.L. 1996. Changes in abundance of demersal fish species in the North Sea between 1906–1909 and 1990–1995. ICES Journal of Marine Science, 53: 1054–1062. Rodríguez-Cabello, C., F. Sánchez, A. Fernández and I. Olaso. 2001. Is the lesser spotted dogfish (Scyliorhinus canicula) from the cantabrian sea, a unique stock ?. ICES CM 2001/O:06, 18 pp. Rodríguez-Cabello, C., F. Velasco and I. Olaso, 1998. Reproductive biology of lesser spotted dogfish Scyliorhinus canicula (L., 1758) in the Cantabrian sea. Sci. Mar., 62(3): 187–191. Rogers, S.I. and Ellis, J.R. 2000. Changes in the demersal fish assemblages of British coastal waters during the 20th century. ICES Journal of Marine Science, 57:866–881. Rosa, A., Menezes, G., Melo, O., Pinho, M.R., 2005 (Submited). Weight-length relationships of 33 demersal fish species from Azores Archipelago. Fisheries Research. Rosa, A.G., 2002. Idade e crescimento da raia-lenga, Raja clavata (Linnaeus, 1758), no Arquipélago dos Açores. Relatório de Estágio do curso de Licenciatura em Biologia Marinha e Pescas. Universidade do Algarve, Faro. 60 pp.

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Sánchez, F. 1993. Las comunidades de peces de la plataforma del Cantábrico. Publ. Espec. Inst. Esp. Oceanogr. 13, 137 pp. Sánchez, F., de la Gándara, F., and Gancedo, R. 1995. Atlas de los peces demersales de Galicia y el Cantábrico, Otoño 1991–1993. Publ. Esp. Inst. Esp.Oceanogr. 20, 99 pp. Sánchez, F., Blanco, M., and Gancedo, R. 2002. Atlas de los peces demersales y de los invertebrados de interés comercial de Galicia y el Cantábrico. Otoño 1997–1999. Ed. CYAN (Inst. Esp.Oceanogr.), 158 pp. SCRS. 2004. Report of the Standing Committee on Research and Statistics, ICCAT SCRS. Serra Pereira B. 2005. Age and growth of Raja clavata Linnaeus, 1758– evaluation of ageing precision using different types of caudal denticles. Report presented in WGEF 2005, Lisbon 14-21 June. Silva, H. M. 1988. Growth and reproduction of kitefin shark Dalatias licha (Bonnaterre, 1788) in Azorean waters. ICES C.M. 1988/G:21. 15 pp. Silva, H. M. 1987. An assessment of the Azorean stock of kitefin shark, Dalatias licha (Bonn., 1788). ICES C.M. 1987/G:66. 10 pp. Simpfendorfer, C.A. 1999. Demographic analysis of the dusky shark fishery in Southwestern Australia. In Life in the slow lane: Ecology and conservation of long-lived marine animals. Ed. by J.A.Musick. American Fisheries Society Symposium, 22:149–160. Simpfendorfer, C.A. and Milward, N.E. 1993. Utilisation of a tropical bay as a nursery area by sharks of the families Carcharhinidae and Sphyrnidae. Env. Biol. Fishes, 37: 337-345. Skjaeraasen, J.E. and Bergstad, O.A. 2001. Notes on the distribution and length composition of Raja lintea, R. fyllae, R. hyperborea and Bathyraja spinicauda (Pisces: Rajidae) in the deep northeastern North Sea and on the slope of the eastern Norwegian Sea. ICES Journal of Marine Science, 58:21–28. Skjaeraasen, J.E. and Bergstad, O.A.. 2000. Distribution and feeding ecology of Raja radiata in the northeastern North Sea and Skagerrak (Norwegian Deep). ICES Journal of Marine Science, 57: 1249–1260. Sosinski, J. 1977. Polish investigations on the Scottish Norwegian spurdog (Squalus acanthias) in 1974. Ann. Biol., Copenhagen, 32: 178–179. STECF, 2003 Report of Ad-Hoc Working Group – Elasmobranch Fisheries. Commission Staff Working Paper. 220pp. Stehmann, M., and Bürkel, D.L.. 1984. Rajidae. In Fishes of the north-eastern Atlantic and Mediterranean, Vol 1, pp. 163–196. Ed. by P. J. P. Whitehead, M.-L. Bauchot, J.-C. Hureau, J. Nielsen and E. Tortonese. UNESCO, Paris, 510 pp. Stott, FC 1982. A note on catches of basking sharks, Cetorhinus maximus (Gunnerus), off Norway and their relation to possible migration paths. Journal of Fish Biology, 21(2): 227– 230. Sullivan, P. J., Lai, H.L., and Gallucci, V.F. 1990. A catch-at-length analysis that incorporates a stochastic model of growth. Canadian Journal of Fisheries and Aquatic Sciences, 47(1): 184–198. Veríssimo A., Gordo, L.S., andFigueiredo, I. 2003. Reproductive biology and embryonic development of Centroscymnus coelolepis in Portuguese mainland waters. ICES Journal of Marine Science, 60: 1335–1341. Walker, P.A. and Hislop, J.R.G., 1998. Sensitive skates or resilient rays? Spatial and temporal shifts in ray species composition in the central and north-western North Sea between 1930 and the present day. ICES Journal of Marine Science, 55: 392–402.

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Yano, K., 1996. Reproductive biology of the black dogfish, Centroscyllium fabricii, collected from waters off western Greenland. Journal of the Marine Biological Association of the United Kingdom, 75: 285–310.

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Annex 1: Participants list

NAME ADDRESS PHONE FAX EMAIL Boris Frentzel Artenschutzexperte der + 49 (0) 40 [email protected] Beyme D.E.G. 431 93400 Biozeutrum Griundel und Zool. Museum, Universitat Hamburg 20146 Hamburg Germany Tom Blasdale JNCC +44 1224 +44 1224 [email protected] Dunnet House 655708 621488 7 Thistle Place Aberdeen AB10 1UZ United Kingdom Maurice Clarke The Marine Institute +353 91 780 +353 1 [email protected] Galway Technology 381 8205078 Park Parkmore Galway Ireland Guzman Diez AZTI + 34 +34 [email protected] Txatxarramendi Ugartea 946029400 946870006 Z/G 48395 Sukarrieta (Bizkaia), Spain Helen Dobby Fisheries Research +44 1224 +44 1224 [email protected] Services 876544 295511 Marine Laboratory P.O. Box 101 375 Victoria Road Aberdeen AB11 9DB United Kingdom Jim Ellis CEFAS +44 1502 +44 1502 [email protected] Lowestoft Laboratory 524300 513865 Lowestoft Suffolk NR33 0HT United Kingdom Ivone IPIMAR + 351 21 + 351 21 [email protected] Figueiredo Avenida de Brasilia 3027131 3017948 P-1449-006 Lisbon Portugal Nils Roar Møreforskning, Ålesund + 47 70011755 [email protected] Hariede P.O. Box 5075 6021 Ålesund Norway Henk Heessen Netherlands Institute for +31 255 564 +31 255 564 [email protected] Fisheries Research 692 644 Haringkade 1 P.O. Box 68 NL-1970 AB IJmuiden Netherlands Graham The Marine Institute + 353 91 [email protected] Johnston GTP, Parkmore, 730490 Galway, Ireland

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Dave Kulka Dept. of Fisheries & +1 709 772 +1 709 772 [email protected] Oceans 2064 5469 Northwest Atlantic Fisheries Centre P.O. Box 5667 St John's, Nfld A1C 5X1 Canada Pedro Machado IPIMAR [email protected] Avenida de Brasilia P-1449-006 Lisbon Portugal Joséde Oliveira CEFAS +44 1502 527 +44 1502 524 [email protected] Lowestoft Laboratory 7 27 511 Lowestoft Suffolk NR33 0HT United Kingdom Mario Pinho Departament + 351 292 200 + 351 292 [email protected] Occeanography and 400 200411 Fisheries DOP, Caiz Sta Cruz 9909 862 Horta, azoresPortugal Charlott National Board of [email protected] Stenberg Fisheries P.O. Box 423 401 Gothenburg Sweden

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Annex 2: Technical minutes

Technical Minutes of the Review of Report of the Working Group on Elasmobranch Fishes

Compiled by Mark Dickey-Collas (RIVO) and Beatriz Roel (CEFAS) September 2005

Background

This is the first Elasmobranch Working Group report to come fully under the auspices of ACFM. All of the assessments are exploratory and the fisheries concerned have a long history of being poorly described and monitored. Few targeted fisheries of elasmobranches exist and much of the catch is as bycatch, whether from trawl or line fisheries. With this in mind both reviewers commend the efforts undertaken by the WG to provide advice given the limitations (uncertainty in catch, effort and stock definitions), the paucity of biological data and complications of using data from surveys that are directed at other fish, such as flatfish and gadoids.

General Comments

The approach taken by the report writers was highly appropriate, as the stocks were assessed (in the broadest manner) bearing the individual fisheries and the dynamics of the ecosystem in mind. The authors coped well with the paucity of reliable data. Their descriptions of data sources and the compilation of data sets were strong and clear. Their transparency must be praised. The authors also considered the suitability of methods required for assessment bearing in mind the “nature” of the stocks, i.e. the role of sex ratios, the level of spatial and temporal aggregations, the suitability of CPUE in the analysis and the strengths of different survey types. In general, their pragmatism was highly appropriate when dealing with stocks with such scarce and uncertain data.

Parts of the report were over descriptive, but this is appropriate for the “First” report, but descriptions should be reduced in the following reports. The reviewers would, however, have liked more proof (with references) on the stock definitions which lead each chapter. The term depleted is used in a range of ways throughout the report, and its meaning is unclear. This should be clarified and used in a uniform manner throughout the report.

Whilst much effort was given to how the time series were compiled, the reviewers would have liked to have seen more discussion of data quality. A throw away remark in the introduction refers to “TAC restricted” species being landed as Elasmobranchs (e.g. cod as dogfish in the Irish Sea), thus increasing the reported landings but this is not discussed anywhere else in the report. Some sections of the report confuse description with discussion.

Unfortunately, the report was not easy to review as each chapter had a different format, tables and figures were out of sequence, axis labels were missing in over 30 figures, units were often not defined (usually tonnes) and many references were missing. Slightly greater effort should be spent next year in ensuring that simple stylist and formatting issues do not cloud the issues or discredit the WG’s hard work and intensive labour.

Generally, the Elasmobranch Report is strong and can form the basis for advice from ACFM for some stocks within the ICES area. Crucially and as mentioned by the WG, much more information is needed by species, fishery and area. Greater input into the WG by French and Spanish scientists would also strengthen the report. Essential information on some fisheries and stocks is now missing from the Report.

Specific comments relating to each Chapter follow. Editorial comments have not been included in these minutes but can be obtained from the reviewers, if required.

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1 Introduction

This gives a broad overview and is generally well considered. More information on the general raising procedures for discards and catch would be relevant here (but the large difference between stocks may prevent this being really useful). In some sections certain countries are highlighted as not providing data, whereas in other sections the identities of the nations are kept vague. The approach should be uniform. The recommendations are not well constructed and unclear.

2 Spurdog in the North East Atlantic

More evidence for the stock identity required.

Fishery section confusing and needs simplification.

The interpretation of Figures 2.7 and 2.10 is difficult and the figures need greater explanation.

Section 2.6. In relation to previous studies, the Bayesian assessment, the model assumptions such as constant r and K are standard when data are sparse. Also, assuming that the stock biomass was at K at the start of the time series is a common assumption which was proved to be defensible for a number of stocks (see Polachek et al. 1993, Fitting surplus production models: comparing methods and measuring uncertainty. Can J. fish. Aquat. Sci. 50, 2597-2607 ) results being insensitive to the assumed ratio B0/K. So the reviewers support the methods used.

Section 2.6.2 Data exploration and preliminary modelling. The survey index of abundance needs to be better described. If the Scottish survey was used what is the area covered by the survey and does it cover the stock distribution. Present the time-series on a table or graph. Why are the survey data patchy?

It would be useful to show the objective function, basically what was minimised. Although preliminary, it would be of interest and useful to present some of the results such as estimated total virgin biomass as well as a Figure showing model fit to data. There was no comment about the highly variable estimates of biomass given by each of the previous methods used.

In future, rather than considering alternative assessment methods the WG should concentrate on obtaining an appropriate index of abundance and improved estimates from biological data.

2.7. Effects of maximum landing size. This is a valuable study and should be taken further. In particular, the reviewers would like to see tests of the sensitivity of the results to the von Bertalanffy growth parameters and the Gauld recruitment parameters. Also, is it defensible to assume that recruitment is only a function of female fecundity?

Also on the positive side, the study shows that under the present state of the stock (in terms of depletion and size structure) a maximum landing size of anything over 80 cm is toothless.

The reviewers were not completely convinced that the wording of the management considerations was appropriate, and would like to see more simulations of recover from collapse.

3 Deep-water sharks in the North East Atlantic (ICES Areas I-XIV)

General. A valuable effort made by the WG to reconstruct the catches and identify problem areas. Still, work needs to be done, how is liver and oil converted into species live weight? This is one of the strongest chapters of the report.

The Fisheries section was clear and well written.

CPUE indices. Given even distribution of the sharks considered, by catch CPUE seems an appropriate index of abundance. However, possible changes of fishing patterns and composition of the fleet need to be taken into account by modelling the CPUE using for example GLMs. A rigorous analysis of CPUE data is required.

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Stock assessment. Results from using the CEDA package need to be shown, in particular the model fit to all the data. Justification for discarding some of the data is not clearly presented: years 91 – 93 the fishery was not fully developed, does that mean that the catch reported may be an underestimate? Years 2000 and 2001, the reviewers understand that there are no direct estimates of abundance other than the CPUE time-series so, which of the supporting evidence is missing? The reviewers would rather see a noisy fit to all the data than a better fit to arbitrarily selected data. What is the model estimate of the ratio of current biomass over initial? Please table model results: point estimates and confidence intervals.

A paragraph comparing the results from this analysis with previous ones would be useful.

Management considerations. The stocks are classified as depleted although model parameters which could lead to such interpretation seem to be poorly estimated.

4 Other deepwater sharks from the northeast Atlantic (ICES sub-areas IV – XIV)

The reviewers note that little information is available and hence no stock assessment studies were undertaken. However just stating sources, rather than showing data is not very constructive. The WG and the reviewers note that much more information is needed on discarded sharks.

5 Kitefin shark (entire ICES area)

This is one of the weakest chapters and tended to be confused and unclear. The chapter is dominated by the assessment for the Azores, and then little attention is given to Kitefin shark in the other areas. It should be made clear that the Management considerations only refer to the Azores.

The stock assessment presented is based on the work of Silva et al 2003 which is not in the References list. Was that work peer-reviewed? There is a suggestion of the stock being overexploited based on the probability of the Biomass 2001 being less than BMSY , although this is closely linked to the model parameter m. In the worse case scenario the probability of the stock being overexploited is 85%. The posterior distribution of the depletion ratio is wide. The report acknowledges that the CPUE may not reflect real abundance trends and if that is the case effort needs to be concentrated on obtaining a consistent time-series of abundance.

6 Porbeagle in the North East Atlantic (Sub-areas I-XIV)

The stock is included in TOR d) which is probably unrealistic given the quality of the data, the report states clearly that catch data are incomplete for probably all years. It is a sad indictment of the state of elasmobranch fisheries data, that a stock such as Porbeagle with a long and targeted fishery in the past, does not have a useable time series.

Apparently the stock was depleted by the 1970’s this based on the fact that the directed fishery stopped because it was not profitable. No fishery independent information presented to substantiate the “depleted” status. Although this data may not be suitable to determine the relative temporal abundance of porbeagle. The biology of the stock: low productivity and possibility of targeting spawning aggregations makes it vulnerable to fishing operations.

Not clear to the reviewers the context of the reference to the Canadian situation, although the experience in Canada is relevant it should be kept only as a reference and point of departure for the assessment of the NEA stock. Comments relating to sustainable catches in the long term and MSY are confusing. Further, is the WG suggesting that something on the lines of the Allowable Harm Assessment should be applied in EU waters?

No comments are given on how to estimate such low F’s mentioned in the MSY in management considerations (0.04), given the noise in any assessment data.

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7 Basking Shark in the northeast Atlantic (ICES Areas I-XIV)

Listed under Appendix II of CITES. Protected species in the UK. No directed fisheries for this species. Declining trend in catches since 1988 (Kunzlik, 1988). Advice appropriate.

8 Demersal Elasmobranchs in The Barents Sea

Little information available for stock assessment. Time-series of abundance from survey cruises are provided for five skate species but are still very short, four years, and do not show clear trends. Effort to continue collecting data for stock assessment should continue.

9 Demersal Elasmobranchs in The Norwegian Sea

Chapter was thin, but this reflects the paucity of data.

10 Demersal Elasmobranchs in the North Sea, Skagerrak, Kattegat and Eastern Channel

The most import demersal elasmobranch is Raja clavata. Assessment presented was undertaken by EU DELASS project.

Skates and rays. Results from a GIS analysis of IBTS data is presented for the period 1990 – 2004 addressing TOR b). In addition to the maps depicting distribution, measures of spatial extent and degree of concentration were calculated for three periods between 1990 and 2004. The WG group appears to draw conclusions on stock status by combining those two measures in an ad-hoc way. Work could be done to combine those indices in a more rigorous way to produce an index of stock status ideally annual rather than for a period.

Raja clavata GLM model of survey abundance by length class. Good approach taken using the survey data only given the limitations of the commercial data. It is appropriate to use Boolean variables given the large number of zeros. For completeness the reviewers would have used all the data when using the catch in numbers, including the zeros but adding a constant to be able to log-transform. Using only the positive stations means the zeros are being ignored, and they are informative. Another suggestion is to group the length classes, for example: < 40 cm and >40cm as large specimens are not well represented in the catches. For stock assessment purposes and to provide quantitative advice it would be useful to perform the analysis annually using area, season and year as explanatory variables to obtain an annual index.

11 Demersal Elasmobranchs at Iceland and East

No comment except more data need to be made available to the working group.

12 Demersal elasmobranchs at the Faroe Islands

No comment except more data need to be made available to the working group.

13 Demersal Elasmobranchs in the Celtic Seas (ICES Divisions VI & VII (Except Area VIId))

The WG has made a good effort to summarise existing information on landings and discards in fisheries which are predominantly by-catch. Given limitation in the reported landings the focus in the assessment should be in the scientific surveys. Although the surveys were not designed to assess elasmobranchs they could still provide an indication of trends as long as they cover the distribution area and the gear selectivity is appropriate. These species of elasmobranchs are likely to have a patchy distribution so it is not surprising that the catch rates will be variable, but then an analysis similar to the one undertaken for the North sea stocks (distribution area and density) could be useful. A preliminary assessment was undertaken for Leucoraja naevus by the DELASS project, state what the results showed for future reference and long term trends.

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The methods on how discards are estimated, or can be estimated needs to be described.

14 Demersal elasmobranchs in the Bay of Biscay and Iberian Waters (ICES Subarea VIII and Division (IXa)

Fishery text was a little unclear.

Survey and length frequency time-series are too short to be indicative of stock trends. Given the data available, biomass models and survey only methods seem most appropriate to assess S. canicula. More information from the surveys would be useful.

How are discards estimated?

15 Demersal Elasmobranchs in the Azores and Mid-Atlantic Ridge

Apart from species identification problems, landing parts of rays or sharks (trunks) should not cause a problem as long as there is no trend between trunk weight and whole weight.

Management considerations are appropriate.

16 Other pelagic species from the northeast Atlantic (ICES sub-areas I – XIV)

This chapter just seemed to end without a conclusion.

17 Elasmobranch NEI landings in ICES area (I – XIV)

This would be better placed in an appendix rather than given a full chapter.