Summer survival and activity patterns of estuary feeding anadromous Salmo trutta |
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Authors: | Hannele M Honkanen Jessica Rodger Alastair Stephen Keith Adams James Freeman Colin E Adams |
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Institution: | 1. Scottish Centre for Ecology and the Natural Environment, Institute of Biodiversity, Animal Health & Comparative Medicine, University of Glasgow, Glasgow, UK;2. Scottish and Southern Energy, Perth, UK;3. Loch Lomond Fisheries Trust, Glasgow, UK |
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Abstract: | There is generally a very poor understanding of how anadromous brown trout, Salmo trutta, use marine ecosystems. In this study, we use acoustic telemetry techniques to test four alternative hypotheses for estuarine coastal habitat use by this species on a population in the Clyde, west-central Scotland. Anadromous brown trout in their second (or more) summer feeding in the marine environment did not show patterns of estuarine use predicted from studies on other populations of this species. They did not (a) use the inner Clyde Estuary as a staging post for onward migration to open coastal waters, nor did they (b) pass through the estuary rapidly nor did they (c) make multiple incursions into freshwater. In contrast, fish utilised a very geographically constrained area of the inner estuary (<8 km in length), within which fish were highly mobile, exhibiting more activity during a flooding tide and exhibited high survivorship compared with reports from other studies. The reasons why estuarine use by anadromous brown trout in the Clyde may differ from that reported elsewhere is discussed. |
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Keywords: | acoustic telemetry habitat use partial migration Salmo trutta |
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