Habitat utilization of juvenile Atlantic salmon (Salmo salar L), brown trout (Salmo trutta L) and Arctic charr (Salvelinus alpinus (L)) in two lakes in northern Norway

Habitat utilization of juvenile Atlantic salmon, brown trout and Arctic charr was investigated in two lakes in northern Norway during the ice-free season. Both the vertical distribution and the distribution among different habitat types were studied by gillnetting with small mesh sized gillnets (8-15 mm) in different habitats. Salmon and trout were predominantly caught in the littoral and sublittoral zones (0-6 m depth). Access to shelter seemed to be the most important factor determining the horizontal distribution of small salmon and trout. Most of these fish were caught in stony or vegetated habitats, while few salmon and trout were caught on sandy locations or in the pelagic zone. In one of the lakes, there were significantly higher catch races of salmon than of trout in the stony littoral (0-3 m), while in the other lake there were no significant differences in spatial distribution between these two species. Charr were primarily found in the profundal, sublittoral or pelagic zones of the lakes.