CE20008_1 Western European Shelf Pelagic Acoustic Survey (WESPAS) 2020 Leg 1

The WESPAS survey is an annual multi-disciplinary survey that is conducted by the Marine Institute to the west of Ireland and the British Isles from northern Bay of Biscay to the Hebrides from coastal waters out to the shelf edge. The survey is usually conducted over 2 legs in June and July each year. The objectives are to collect single (split) beam acoustic data on boarfish, herring, horse mackerel, sprat and mackerel aggregations within the pre-determined survey area. An age stratified estimate of biomass and abundance of the target species is generated from the survey data. Biological samples are collected from directed trawling on fish echotraces to determine age structure, size and maturity characteristics of the target stocks. Vertical CTD casts are deployed to determine hydrographic conditions and the extent of shelf frontal regions. Plankton samples using vertical net casts are used to determine biomass of zooplankton and the spatial extent of areas of distribution. Visual abundance surveys by observers for marine mammals and seabirds are also conducted throughout the survey area. Omni-directional sonar (Simrad SU90) is used to collect data on the aggregation morphology and behaviour of fish species. 43 CTDs were carried out during leg one of the survey. The main purpose of the cruise was to determine the relative abundance of the target species. This information is then used to determine catch rates and management advice for the following year.