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Working Group on Elasmobranch Fishes (WGEF)

report
posted on 18.11.2022, 13:13 authored by ICESICES

ICES WGEF is responsible for providing assessments and advice on the state of the stocks of sharks, skates, and rays throughout the ICES area. In 2022, WGEF provided advice for 29 stocks of rays and skates distributed the Celtic Seas and Bay of Biscay/West Iberia ecoregions and two stocks of sharks distributed in the Northeast. Some of the advice changed greatly compared to previous advices as data and modes were revised in a benchmark process for five stocks including the two stocks of sharks (porbeagle and spurdog) and three stocks of skates (cuckoo ray in the Celtic Seas and Bay of Biscay, undulate ray in the English Channel and thornback ray in the Bay of Biscay). For the latter, in addition to changes in the method, the stock structure was revised and the previous stock unit for the whole Bay of Biscay was split into two units, one in ICES divisions 8.a–b and 8.d (eastern shelf of the Bay of Biscay) and one in Division 8.c (Cantabrian Sea).

The advices for four out of five stocks with the new assessment methods recommend much larger catches than previously. Spurdog was assessed to have significantly rebuilt after depletion and a catch of no more than 17 353 tonnes in 2023 was advises compared to the previous advice for no target fisheries. For porbeagle, the previous advice for 0 catch was replaced by an advice for no more than 219 and 231 tonnes in 2023 and 2024, respectively. Undulate ray in the English Channel was assessed to have rebuild to high levels following periods of prohibition of catches (2009–2014) and low precautionary TACs. The recommended dead catch (including possible dead discards) was advised at about 20 times the amount of the previous advice (i.e.4836 tonnes in 2023). The advised landings for cuckoo ray are about twice the previous level (i.e. 7826 tonnes in 2023). In contrast, for thornback ray in the eastern Bay of Biscay, advised landings have decreased compared to previous landings advice. Lastly for thornback ray in the Cantabrian Sea; a trends-based assessment was carried out and suggested a recent decline in the stock biomass.

WGEF applied new empirical methods for stock assessment and catch advice developed by WKLIFE X. These methods were applied to 12 category 3 stocks to provide advice within the ICES MSY framework. The 10 category 5 and 6 stocks were not assessed and advices were provided using the precautionary approach.

Estimates of discards remain uncertain because elasmobranchs are mostly bycatch in various fisheries and only very high sampling effort would allow for precise and unbiased estimates. Further, recent studies confirmed high survival of discarded elasmobranchs for several stocks, but this is stock- and fleet-specific so the relationship between discards and dead catches is available for a few stocks only. For most stocks, advice is provided in terms of landings.

Lastly, a benchmark for three North Sea stocks is proposed for 2023. It will be the first time these stocks will go through a benchmark. In addition, a second WKSKATE workshop that would examine the availability and use of surveys for skate and ray stocks in the Celtic Sea and Iberian waters is being planned for 2024. 

History

Published under the auspices of the following ICES Steering Group or Committee

  • FRSG
  • ACOM

Published under the auspices of the following ICES Expert Group or Strategic Initiative

WGEF

Series

ICES Scientific Reports

Volume

4

Issue

74

Contributors (Editors)

Jurgen Batsleer, Pascal Lorance

Contributors (Authors)

Thomas Barreau • Jurgen Batsleer • Loïc Baulier • Gérard Biais • Katinka Bleeker • José A. A. De Olivera • Jim Ellis • Christopher Griffiths • Klara Jakobsdottir • Graham Johnston • Claudia Junge • Laura Lemey • Wendel Lleal • Pascal Lorance • Tanja Miethe • Teresa Moura • Marlén Knutsen Myrlund • Sophy Phillips • Cristina Rodríguez-Cabello • Régis Santos • Matthias Schaber • Joana Silva • Paddy Walker

ISSN

2618-1371

Recommended citation

ICES. 2022. Working Group on Elasmobranch Fishes (WGEF). ICES Scientific Reports. 4:74. 848 pp. http://doi.org/10.17895/ices.pub.21089833