Diet of Arctic charr (Salvelinus alpinus (L.)) and brown trout (Salmo trutta L.) in sympatry in two high altitude alpine lakes |
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Authors: | L Cavalli R Chappaz A Gilles |
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Institution: | (1) Laboratoire d'hydrobiologie, UPRES Biodiversité, Université de Provence, 1–3 Pl, Victor Hugo, F–13331 Marseille 03, France |
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Abstract: | Lake Pisses and Lake Labarre are two oligotrophic high altitude alpine lakes that have sympatric populations of Arctic charr
and brown trout. These two lakes have similar morphometric, physical and chemical characteristics. The zooplanktonic and benthic
fauna show little diversity. But the density of benthos (Chironomidae) and zooplankton is higher in Lake Pisses. The fish
fauna of Lake Pisses is slightly more abundant than that of Lake Labarre, althought in both lakes fish density is low. A study
of the diet of the two species revealed differences. In Lake Pisses, where the food supply is better, Arctic charr takes exclusively
pelagic and benthic prey, whereas in Lake Labarre it also takes exogenous prey and thus comes into competition with trout.
Length and body weight growth rates for Arctic charr are higher in Lake Pisses than in Lake Labarre. For trout, maximum length
recorded was in Lake Pisses. The results show that the abundance of Chironomidae favours coexistence of the two species in
Lake Pisses and confirm that, in the face of shortage of food, Arctic charr is better adapted than trout.
This revised version was published online in July 2006 with corrections to the Cover Date. |
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Keywords: | diet high altitude lake Salvelinus alpinus Salmo trutta extreme oligotrophic conditions |
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