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Report of the Working Group Onelasmobranch Fishes (WGEF). ICES CM 2006/ACFM:31

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Report of the Working Group Onelasmobranch Fishes (WGEF). ICES CM 2006/ACFM:31 ICES WGEF Report 2006 ICES Advisory Committee on Fisheries Management ICES CM 2006/ACFM:31 Ref. LRC Report of the Working Group on Elasmobranch Fishes (WGEF) 14–21 June 2006 ICES Headquarters 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 2006, ICES Headquarters. ICES CM 2006/ACFM:31. 291 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. © 2006 International Council for the Exploration of the Sea. ICES WGEF Report 2006 | i Contents 1 Introduction ............................................................................................................. 1 1.1 Terms of Reference ......................................................................................... 1 Description..................................................................................................... 3 1.2 Participants ...................................................................................................... 4 1.3 Background...................................................................................................... 4 1.4 Future planning of the work of the group........................................................ 5 1.5 Current projects or meetings of relevance to the WG...................................... 7 1.5.1 Working Group on Fish Ecology........................................................ 7 1.5.2 International Bottom Trawl Survey Working Group.......................... 7 1.5.3 Length based assessment methods group............................................ 7 1.5.4 Theme Session on Elasmobranch Fisheries Science, 2005................. 7 1.5.5 Seafish/Supermarket initiative in the UK ........................................... 8 1.5.6 IUCN Redlist Process for the northeast Atlantic ................................ 8 1.5.7 Shark Alliance .................................................................................... 8 1.5.8 Deepwater gillnetting.......................................................................... 9 1.5.9 Council Regulation on the removal of fins of sharks.......................... 9 1.5.10 Convention on International Trade in Endangered Species (CITES) ............................................................................................ 10 1.6 Catch data ...................................................................................................... 10 1.7 Ad hoc requests.............................................................................................. 13 1.7.1 Recommendations to NEAFC on pelagic sharks.............................. 13 1.7.2 Recommendations to Germany on CITES listings on porbeagle and spurdog....................................................................................... 14 1.8 Provision of data before working group ........................................................ 14 1.9 Recommendations ......................................................................................... 15 1.10 References ..................................................................................................... 16 1.11 Working documents and presentations made at the group ............................ 16 2 Spurdog in the North East Atlantic...................................................................... 19 2.1 The Fishery.................................................................................................... 20 2.1.1 The fishery in 2005........................................................................... 20 2.1.2 ICES advice applicable in 2005 and 2006 ........................................ 20 2.1.3 Management applicable.................................................................... 21 2.2 Catch Data ..................................................................................................... 22 2.2.1 Landings ........................................................................................... 22 2.2.2 Discards ............................................................................................ 23 2.2.3 Quality of the catch data ................................................................... 23 2.3 Commercial length frequencies ..................................................................... 23 2.3.1 Landings length compositions .......................................................... 23 2.3.2 Discard length compositions............................................................. 23 2.3.3 Quality of data .................................................................................. 23 2.4 Commercial catch-effort data ........................................................................ 24 2.5 Research vessel surveys................................................................................. 24 2.5.1 CPUE................................................................................................ 25 2.5.2 Length distributions.......................................................................... 26 2.6 Mean length, weight, maturity and natural mortality-at-age ......................... 27 2.7 Exploratory assessment model ...................................................................... 27 2.7.1 Introduction ...................................................................................... 27 ii | ICES WGEF Report 2006 2.7.2 Population dynamic model ............................................................... 28 2.7.3 Life-history parameters..................................................................... 30 2.7.4 Likelihood function .......................................................................... 30 2.7.5 Results .............................................................................................. 32 2.7.6 Retrospective analysis ...................................................................... 32 2.7.7 Sensitivity analysis ........................................................................... 32 2.7.8 Discussion......................................................................................... 33 2.8 Comparison with Previous studies................................................................. 33 2.9 Quality of the Analytic Assessment............................................................... 34 2.9.1 Catch data ......................................................................................... 34 2.9.2 Survey data ....................................................................................... 34 2.9.3 Biological information...................................................................... 35 2.9.4 Model formulation............................................................................ 35 2.10 Simulation of effects of Maximum landing length regulations ..................... 35 2.11 Reference points ............................................................................................ 36 2.12 Management considerations .......................................................................... 36 2.13 References ..................................................................................................... 37 3 Deepwater “siki” sharks in the northeast Atlantic ............................................. 77 3.1 The fishery..................................................................................................... 77 3.2 Biological composition of the catch .............................................................. 78 3.3 Mean length, weight, maturity, natural mortality and recruitment ................ 80 3.4 Catch per unit effort....................................................................................... 80 3.5 Data exploration ............................................................................................ 80 3.6 Assessment .................................................................................................... 81 3.6.1 Previous assessments ........................................................................ 81 3.6.2 Exploratory assessment .................................................................... 81 3.7 Quality of CPUE data.................................................................................... 81 3.8 Management considerations .......................................................................... 82 3.9 References ..................................................................................................... 82 4 Other deepwater sharks from the northeast Atlantic (ICES Subareas IV– XIV) ...................................................................................................................... 101 4.1 The fishery................................................................................................... 101 4.1.1 Advice and management applicable ............................................... 101 4.1.2 Description of the fishery ............................................................... 101 4.2 Fishery-independent information................................................................. 103 4.3 Catch per unit of
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