Report of the Working Group on Elasmobranch Fishes (WGEF)

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 F_msy with a biomass just above B_msy. Using the 15th percentile of the removals at F_msy 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 F_msy with a biomass above B_msy. 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 F_msy with a biomass above B_msy. The 15th percentile of the removals at F_msy 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.