Joint EIFAAC/ICES/GFCM Working Group on Eels (WGEEL)
The Joint EIFAAC/ICES/GFCM Working group on eels (WGEEL) met from September 6–9 and 12–20 September 2022 in Toombridge, Northern Ireland, to provide the scientific basis for the ICES advice on fishing opportunities and conservation aspects for the European eel and address requests from EIFAAC and GFCM.
WGEEL assessed the state of the European eel and its fisheries, collated and analysed biometric data, reviewed and summarized available data on eel quality, further identified issues specific to the Mediterranean region, discussed the use of landings data for the assessment (following WKFEA) and reported on any updates to the scientific basis of the advice, new and emerging threats or opportunities.
The recruitment of European eel declined markedly from 1980 to 2011. The glass eel recruitment compared to that in 1960–1979 in the “North Sea” index area was 0.5% in 2022 (provisional) and 0.6 % in 2021 (final). In the “Elsewhere Europe” index series it was 9.7 % in 2022 (provisional) and 5.5% in 2021 (final), based on available data series. For the yellow eel data series, recruitment for 2021 was 19% (final) of the 1960–1979 level; the 2022 data collection for yellow eel is ongoing. Time-series from 1980 to 2022 show that glass eel recruitment remains at a very low level.
Analyses of data series on yellow or silver eel abundance (162 series analysed) and grouped biometric data were re-run this year and show the potential of the yellow and silver eels’ series to improve the stock assessment. A graphical analysis of the new biometric data integrated in the database, 1.2 million individual data and 4908 grouped data (combining length, weight and age data), was carried out to identify future analyses and information that might be missing. To identify the potential of Length-Based Models for stock assessment, a preliminary overview of the models, the input needed and of the assumptions was realised.
A collation and integration of available data relating to eel quality – lipid content, parasites and virus, and contaminants - was carried out and examples of analyses and visualisation presented. A review of recent publications relating to eel quality was carried out. Recommendations for improving submission and harmonisation of relevant data, and using eel quality in the context of stock assessments are proposed.
Available landings data was reviewed and scoped with potential methods for their use in the assessment of the European eel in preparation of a workshop foreseen in the WKFEA roadmap. Currently, landings data cannot be included in the assessment but follow up work for their use in a potential spatial assessment approach is recommended.
In summary, besides updating recruitment time series, further progress was made in collating and analysing individual biometric data and eliciting there use in future assessment, particularly for a spatial assessment approach. Significant progress was made towards utilizing data on eel quality but its use in the assessment is currently data limited.
Published under the auspices of the following ICES Steering Group or Committee