Loading...
Western European Shelf Pelagic Acoustic Survey (WESPAS) Survey Report 2025
O'Donnell, Ciaran O'Malley, Michael Mullins, Eugene
O'Donnell, Ciaran
O'Malley, Michael
Mullins, Eugene
Citations
Altmetric:
Keywords
Date
2025-11
Publisher
Marine Institute
Collections
Files
Loading...
WESPAS Report 2025.pdf
Adobe PDF, 7.96 MB
Research Projects
Organizational Units
Journal Issue
Abstract
The 2025 Western European Shelf Pelagic Acoustic Survey (WESPAS; CE25009) was conducted aboard the RV Celtic Explorer from 18 June to 29 July 2025 to assess the abundance, biomass, and distribution of key small pelagic fish species, including boarfish, western horse mackerel, and herring, across shelf seas from northern Biscay to the Hebrides. The fisheries‑independent trawl‑acoustic survey covered 60,374 nmi² between 47°30′N and 58°30′N using systematic parallel transects, with effort and timing comparable to 2024. Targeted midwater trawls were undertaken on insonified echotraces to determine species composition and biological characteristics, including length, weight, sex, maturity, and age. Genetic tissue sampling, hydrographic profiling, zooplankton sampling, and marine mammal observations were also conducted.
The survey provides a snapshot index of relative abundance and biomass at the time of sampling. Malin Shelf herring total stock biomass (TSB) was estimated at 56,078 t, with spawning stock biomass (SSB) of 7,142 t, representing an 89% decline in SSB compared to 2024 and the lowest value in the time series. Boarfish TSB and abundance declined by 36% and 44%, respectively, to 279,376 t and 6.67 billion individuals. In contrast, horse mackerel TSB increased by 29% to 96,204 t. Celtic Sea herring were not observed and are excluded from stock assessment inputs.
Description
Funder
Citation
O'Donnell, C., O’Malley, M., Mullins, E., Daly, E., & De Loose, E. (2025). Western European Shelf Pelagic Acoustic Survey (WESPAS) Survey Report 2025 . Marine Institute, Ireland