Movement of wild and experimentally stocked brown trout, Salmo trutta L., before and after a flood in a small Austrian stream |
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| Authors: | S Weiss & H Kummer |
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| Institution: | Abteilung für Hydrobiologie, Universität für Bodenkultur, Vienna, Austria |
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| Abstract: | Weirs and traps were used to monitor the movement of two strains of stocked brown trout, Salmo trutta L. Within 24 h of stocking, 15% ( n = 13) of a Danish strain and 21% ( n = 19) of a hybrid strain moved at least 100 m from their release site. In the following 5–6 days, no further movement was found for Danish fish, but hybrid fish continued to move, totaling 32% ( n = 29) of the fish stocked. During this same period, 36 wild brown trout (≈ 3.5% of the population) were captured, moving over the weirs. Two weeks later, and one week after a flood, 70% ( n = 59) of the Danish strain were recovered within their release sites and 89% ( n = 76) were recovered during an electric fishing survey within the 3.5-km-long experimental area. In contrast, 43% ( n = 31) of the hybrid strain were recaptured in their release sites and 49% ( n = 45) within the experimental area. The total recapture of wild adult fish was only 16% ( n = 41). The flooding event was insignificant in comparison with strain-specific behaviours in determining patterns of movement and residency.Austria, brown trout, floods, movement, stocking. |
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