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Comparative life‐history characteristics of native and hatchery‐reared brown trout, Salmo trutta L., in a sub‐Alpine reservoir
Author(s) -
Hesthagen T.,
Flòystad L.,
Hegge O.,
Staurnes M.,
Skurdal J.
Publication year - 1999
Publication title -
fisheries management and ecology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.693
H-Index - 55
eISSN - 1365-2400
pISSN - 0969-997X
DOI - 10.1046/j.1365-2400.1999.00138.x
Subject(s) - brown trout , hatchery , salmo , trout , biology , fishery , intraspecific competition , competition (biology) , rainbow trout , ecology , fish <actinopterygii>
Wild and non‐native hatchery‐reared brown trout, Salmo trutta L., released when 2 summers old, were caught in the littoral habitat of Vinstervatna Reservoir, southern Norway. Hatchery‐reared brown trout grew more slowly and had a smaller asymptotic length (293 ± 71 mm CL) than native fish (391 ± 56 mm CL). Hatchery‐reared brown trout also exhibited significantly shorter life spans than native fish. This category consisted mainly of individuals aged 2+ and 3+ years, and only 1.5% of the specimens were aged ≥5 years. The ages of the native fish in the sample were between 2 and 8 years, and the most abundant age groups of trout were 4+ and 5+ years. It is suggested that the differences in life‐history characteristics are related to adaptations by the native trout to the local environmental conditions. In this reservoir, which has a limited food supply as a result of water level fluctuations and a high level of inter‐ and intraspecific competition, environmental effects might be significant.