Working Group on Acoustic and Egg Surveys for small pelagic fish in Northeast Atlantic (WGACEGG; outputs from 2025 meeting)

WGACEGG coordinates and validates the methodology of acoustic and egg surveys of several pelagic stocks in ICES areas 6–9. In 2025, spring (PELAGO, PELACUS, PELGAS, BIOMAN, WESPAS) and autumn (ECOCADIZ RECLUTAS, IBERAS, JUVENA, PELTIC, C-PAS) surveys were completed with near synoptic coverage of shelf seas from the Gulf of Cadiz to the Celtic Sea. Results were presented and discussed with members of WGHANSA and were considered reliable.Anchovy biomass was high in divisions 9a and 8abc, with indications of strong recruitment, and a recovery was observed in division 7ef relative to 2024. Sardine biomass increased markedly, reaching record-high abundances in divisions 9a, 8abc, and 7ef. Sprat densities were below average in core areas of the Bay of Biscay and above average in Northern Scotland, while horse mackerel abundance was above average across all areas. Altantic mackerel was mainly concentrated in the north of the Bay of Biscay, very close to the coast and in the Iberian Peninsula north of Lisbon. Chub mackerel distribution was above average in the Cantabrian Sea, below average in Southern Iberia, and close to average elsewhere. Blue whiting densities were average, except for high density patches West and North to Ireland and in the North-Western BoB. Lower than average patches were observed West to Scotland and on NW Iberian coast. Boarfish global density has increased since 2020, with higher-than-average concentrations observed in 2025 between 50° and 58°N and lower-than-average values near the shelf edge in the Celtic Sea and the Bay of Biscay. Herring densities were lower than average south and north of Ireland and close to average elsewhere.Spatial patterns and environment context: Multi survey gridded analyses of acoustic densities confirmed coherent, species-specific spatial patterns across ICES areas 6–9. Environmental conditions in 2025 were broadly consistent with recent years. Egg distributions derived from CUFES and DEPM surveys were spatially consistent with adult distributions, supporting the robustness of survey outputs.Indices comparisons and methodological developments: Comparisons of acoustic and DEPM indices for anchovy and sardine in the Bay of Biscay identified a tipping point around 2011. For anchovy, post 2011 relationships suggest higher daily fecundity, while for sardine the slope decreased; no sign of bias was detected in 2025 anchovy indices. Methodological developments included: (i) a simple calibration method to quantify multibeam beam overlap, enabling improved near surface biomass correction; (ii) in situ target strength estimates from commercial platforms; (iii) explicit assessment of uncertainty in echogram scrutinising; (iv) deep learning echogram segmentation with encouraging agreement in NASC; (v) simulations of target strength and depth effects on anchovy biomass; and (vi) spatially explicit DEPM models reducing uncertainty in egg production parameters. The ICES TIMES Survey Protocol for DEPM was published in 2025, and coordination and standardisation of surveys and data products continued. Correction (03/03/2026): A new version has been uploaded with a correction of the authors name. Correction (03/03/2026): A new version has been uploaded with a correction of the authors list.