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Diet of brown trout in relation to variation in abundance and size of pelagic fish prey
Author(s) -
Hyvärinen P.,
Huusko A.
Publication year - 2006
Publication title -
journal of fish biology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.672
H-Index - 115
eISSN - 1095-8649
pISSN - 0022-1112
DOI - 10.1111/j.0022-1112.2006.00879.x
Subject(s) - brown trout , biology , predation , salmo , trout , pelagic zone , smelt , foraging , piscivore , predator , predatory fish , coregonus , fishery , ecology , fish <actinopterygii>
The seasonal diet of a predator, brown trout Salmo trutta [total length ( L T ) 17–69 cm] and simultaneous density and size‐structure of prey populations, vendace Coregonus albula and smelt Osmerus eperlanus (4–16 cm L T ), in a large boreal lake were analysed and compared in 2001 and 2002. The upper L T limit for consumed prey was c . 40% of the predator L T . All brown trout, however, preferred small (<10 cm L T ) and avoided large (≥10 cm L T ) prey. The results also suggested that equal densities of similar‐sized (4–10 cm L T ) fish of the two prey species led to random foraging on these species by brown trout, but if either one of the prey species predominated (>50%) in the lake, brown trout shifted to foraging on this species almost exclusively. Brown trout diets thus reflected the density dynamics of the two alternative prey species.