LAUSR

Amphipods play the leading role among alien species in Lake Ladoga. In particular, the Baikal species Micruropus possolskii Sowinsky, 1915 is becoming increasingly important here. The purpose of this paper is to present updated data on the appearance of M. possolskii in Lake Ladoga and on the temporal and spatial dynamics of its development and expansion in this water body. The species was initially recorded in the Shchuchiy Bay of Lake Ladoga in 2003. Its spread to the south to the Petrokrepost Bay (where it was recorded in 2017) is shown. The further expansion of the species in Lake Ladoga and its significant quantitative development in the colonized biotopes and possible expansion to Lake Onega and the Neva Bay of the Gulf of Finland are expected.