Acoustic data collected on pelagic fishing vessels throughout an annual cycle: Operational framework, interpretation of observations, and future perspectives

摘要: Acoustic data collection trials on pelagic freezer-trawlers were realised in 2012 during several fishing trips targeting blue whiting west of the British Isles spring, North Sea herring summer, and horse mackerel English Channel Celtic autumn. Echosounders calibrated time- position-stamped logged along path covered by vessels. The acoustic detections recorded different types trawler activity within a trip (‘searching’, ‘stationary’, ‘fishing’) compared between target species. highest proportion time spent for ‘fishing’ was observed fishery (82%), while that value lower (68% 54%). In all fisheries quantified mean fish densities significantly higher than ‘searching’. Changes density magnitudes over before after trawling also showed patterns fisheries. peculiarities exhibited specific is discussed light incorporating them monitoring programs analysis methods can advance ecosystem understanding. Potential future approaches opportunistically vessel are discussed.