Growth characteristics of river perch (Perca fluviatilis L.) in the proximity of trout farm cages (Republic of Karelia)

The article presents the analysis of perch studies results (Perca fluviatilis L.) of lake Vohtozero (Ladoga basin, Karelia) in the proximity of trout cage farms (TCF). It is revealed, that linear and weight growth of perch in the region of Vohtozero TCF significantly increases with age, compared with fish growth in its natural habitat of Karelian lakes. A growth equation for well-fed perch inhabiting near cages (up to 200 m) was developed W = 0,065 • Lt2,6, where W is body weight, g, Lt is body length - AD, cm), It was found that large perch actively consume trout feed and, as a result, have large reserves of abdominal fat. Consequently, such perch significantly differ in weight from the ones inhabiting in distant from TCF parts of the lake.