Do triploid Salmo trutta stocked into a chalk stream in the spring prey on wild Salmo salar smolts?
Abstract The predation impact of recently stocked triploid brown trout, S almo trutta L., on migrating wild A tlantic salmon, S almo salar L., smolts was investigated in two field‐based experiments. The first experiment employed a unique experimental facility to monitor 57 wild S . salar smolts thro...
| Published in: | Fisheries Management and Ecology |
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| Main Authors: | , , , |
| Format: | Article in Journal/Newspaper |
| Language: | English |
| Published: |
Wiley
2013
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| Subjects: | |
| Online Access: | http://dx.doi.org/10.1111/fme.12023 https://api.wiley.com/onlinelibrary/tdm/v1/articles/10.1111%2Ffme.12023 https://onlinelibrary.wiley.com/doi/pdf/10.1111/fme.12023 |
| Summary: | Abstract The predation impact of recently stocked triploid brown trout, S almo trutta L., on migrating wild A tlantic salmon, S almo salar L., smolts was investigated in two field‐based experiments. The first experiment employed a unique experimental facility to monitor 57 wild S . salar smolts through an enclosure containing a known density of stocked S . trutta to determine a predation rate. None of these smolts were preyed upon by the stocked S . trutta . The second experiment investigated the diet of free‐ranging stocked triploid S . trutta in a chalk stream during the spring. Although at least 6% of the free‐ranging stocked triploid S . trutta became piscivorous on P hoxinus phoxinus (L.), the results suggest that large, recently stocked, triploid S . trutta with a high condition factor do not represent a predation threat to wild S . salar smolts. However, it is recommended that a precautionary approach is maintained and the findings are not generalised until further investigation permits explicit management advice to be developed, and that the stocking of large triploid S . trutta is avoided before May/ June (regional variations to apply) each calendar year, where this can reasonably be achieved. |
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