Contribution of the Baikal Amphipod to the Feeding Pattern of Perch in the Littoral Zone of Lake Onega

Abstract. The seasonal feeding pattern of juvenile perch in Petrozavodsk Bay of Lake Onega was studied. It was shown that in the fourth to sixth years of their life, a benthic type of feeding predominates. The fish that inhabit the littoral zone feed actively on the Baikal amphipod, a new food item. During the summer-autumn season, the colonizer accounts for over 50% of the biomass in the stomach of juvenile perch. The invasion of Lake Onega by the Baikal amphipod has thus led to changes in the structure of littoral communities and the availability of a new food item for the fish. Considering the resistance of the Baikal amphipod to unfavorable environmental factors, it is important to study its spatial expansion and the possible penetration of this amphipod via tributaries to other water bodies in the Lake Onega Lake catchment area. Keywords: freshwater ecosystem, perch, trophic interactions, Baikal amphipo