The role of invasive amphipod Gmelonoides fasciatus (Stebbing) in the feeding of perch Perca fluviatilis L. in the littoral zone of Lake Onega

Resumo

The successful invasion of the Baikalian amphipod Gmelinoides fasciatus in the littoral zone of Lake Onega changed significantly the structure of the food resources of fish. High abundance and biomass of these amphipods in macrozoobenthos are the reasons why one of the mass species of littoral fish, perch Perca fluviatilis, turned to active feeding on these crustaceans. In some lake shallow water habitats, the share of this amphipod in the weight of stomach content and occurrence frequency are not less than 50%. Active spread of the amphipod and the dynamics of population indices of this invasive species in Lake Onega indicate the necessity for further studies on the role that G. fasciatus plays in the diet of littoral fish species in the seasonal aspect.