Gulf of Alaska | Fishes and Fish Habitats
Detecting spatial and temporal variation in forage fish school densities using broad-scale aerial surveys Presenter: Dan Donnelly , ddonnelly@usgs.gov, USGS Alaska Science Center
Maymui Arimitsu , marimitsu@usgs.gov, USGS Alaska Science Center Scott Pegau , wspegau@pwssc.org, Prince William Sound Science Center John Piatt , jpiatt@usgs.gov, US Geological Survey Alaska Science Center
Sub-mesoscale variation in abundance and distribution of schooling forage fish such as Pacific herring ( Clupea pallasii ) and Pacific sand lance ( Ammodytes personatus ) has rarely been described in the Northeast Pacific, partly because these species are difficult to survey in a cost-effective manner. We used aerial surveys to assess the distribution of shallow, schooling forage fish in nearshore waters of Prince William Sound, Alaska, and to identify interannual variation in their Sound-wide distribution and abundance. Aerial shoreline surveys were conducted during June and July in 2010, and 2012-2021. Fish schools were counted from the plane, and we validated species and size classifications with boat-based sampling efforts whenever possible. Forage fish densities varied across regions and years, with lowest school densities associated with a prolonged marine heatwave experienced in the North Pacific during 2014-2016. Pacific herring densities varied annually, with several high abundance years interspersed among years of low abundance, whereas Pacific sand lance densities declined sharply after the beginning of the surveys and have only been observed consistently in a few locations since 2013. These surveys demonstrate the efficacy of aerial tracking forage fish populations over wide geographic areas.
Alaska Marine Science Symposium 2023 188
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