Working group on elasmobranch fishes (WGEF)

Type Article
Date 2022
Language English
Author(s) ICES
Contributor(s) Lorance PascalORCID, Baulier LoicORCID, Biais Gerard
Source ICES Scientific Reports/Rapports scientifiques du CIEM (2618-1371) (ICES), 2022 , Vol. 4 , N. 74 , P. 848p.
DOI 10.17895/

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 includ-ing 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 re-vised 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 (Canta-brian 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 de-creased 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 pro-vided 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 avail-able 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.

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