International Council for the Exploration of the Sea
Browse

Report of the Working Group on Elasmobranch Fishes (WGEF)

Download (38.97 MB)
report
posted on 2024-01-25, 08:11 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 2023, WGEF provided advice for 25 stocks of rays and skates distributed in the North Sea ecoregion, the Azores and Mid-Atlantic Ridge, catsharks (Scyliorhinidae) in the Greater North Sea, Celtic Seas and Bay of Biscay and Iberian Coast ecoregions; smooth-hounds in the Northeast Atlantic; and tope in the Northeast Atlantic.

Some of the advice changed greatly compared to previous advice as data and models were revised in a benchmark process for three stocks of skates: thornback ray and spotted ray in the greater North Sea, and blonde ray in the central and southern North Sea and eastern English Channel. For the latter, not only has the methodology been updated, but the stock's structure has also been redefined to incorporate data from the central North Sea (Subarea 4.b), drawing upon survey data, tagging data, and genetic information.

The advice resulting from the new assessment method recommend much larger catches than previously. A SPiCT assessment for thornback ray (rjc.27.3a47d) and spotted ray (rjm.27.3a47d) was conducted using removals since 1999 and two series of biomass indices since 1989. Thornback ray is estimated to be harvested well below Fmsy with a biomass just above Bmsy. Using the 15th percentile of the removals at Fmsy is slightly below MSY and corresponds to a catch advice of 5274 tonnes, which is ~ 2 times higher than previous landings advice. Spotted ray is estimated to be harvested well below Fmsy with a biomass above Bmsy. The 15th percentile of the removals at Fmsy is below MSY, corresponding to a catch advice of 1517 tonnes being ~ 6 times higher compared to previous landings advice. For blonde ray (rjh.27.4bc7d) a SPiCT assessment using removals since 1999 and one series of biomass index was performed. This stock is estimated to be harvested well below Fmsy with a biomass above Bmsy. The 15th percentile of the removals at Fmsy is below MSY, corresponding to a catch advice of 1262 tonnes being ~ 6 times higher compared to previous landings advice.

WGEF applied new empirical methods for stock assessment and catch advice developed by WKLIFE X. These methods were applied to 11 category 3 stocks to provide advice within the ICES MSY framework. For three of those stocks (sho.27.89a, syc.27.8abd and syc.27.8c9a) the assessments were performed but no advice was requested. The 11 category 5 and 6 stocks were not assessed and advice was provided using the precautionary approach.

Discard estimates continue to remain uncertain due to the fact that elasmobranchs are primarily caught as bycatch in a variety of fisheries. Achieving precise and unbiased estimates would require a high level of sampling effort. However, the group has made diligent efforts to collate and harmonize discard data (from 2009 to 2022) categorized by country, fleet segment, and stock code. This has enabled the inclusion of discard data in this report for comprehensive presentation. Nevertheless, for most stocks, advice is provided in terms of landings.

Lastly, a benchmark for three Iberian stocks (rjc.27.9a, rjh.27.9a and rjn.27.9a) is proposed for 2024. It will be the first time these stocks will go through a benchmark.

History

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

  • FRSG

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

WGEF

Series

ICES Scientific Reports

Volume

5

Issue

92

Contributors (Editors)

Sophy Mccully Phillips; Jurgen Batsleer

Contributors (Authors)

Caroline Aas Tranang; Thomas Barreau; Jurgen Batsleer; Loïc Baulier; Katinka Bleeker; Guzman Diaz; Jim Ellis; Ivonne Figueiredo; Christopher Griffiths; Klara Jakobsdottir; Graham Johnston; Graham Johnston; Claudia Junge; Wendel Lleal; Pascal Lorance; Catarina Maia; Tobias Mildenberger; Tanja Miethe; Teresa Moura; Sophy McCully Phillips; Cristina Rodríguez-Cabello; Matthias Schaber; Joana Silva; Morten Vinter

ISSN

2618-1371

Recommended citation

ICES. 2023. Working Group on Elasmobranch Fishes (WGEF). ICES Scientific Reports. 5:92. 837 pp. https://doi.org/10.17895/ices.pub.24190332

Publication language

  • en

File format(s)

  • PDF

Usage metrics

    ICES Scientific Reports

    Licence

    Exports

    RefWorks
    BibTeX
    Ref. manager
    Endnote
    DataCite
    NLM
    DC