Establishment of the Baikalian endemic amphipod Gmelinoides fasciatus Stebb. in Lake Ladoga

Gmelinoides fasciatus Stebb., a small amphipod from the Lake Baikal basin, was discovered in July 1988 in Lake Ladoga, the largest European lake. G. fasciatus likely invaded Lake Ladoga as a consequence of its intentional introduction, aimed at enhancing fish production, in some Karelian Isthmus lakes close to Lake Ladoga's western shore in the early 1970's. Benthos studies conducted in 1989 and 1990 revealed that G. fasciatus was well established in littoral communities along the western and northern shores of Lake Ladoga. G. fasciatus was the dominant species in these littoral communities and contributed over 70% of the macroinvertebrate biomass. The species was abundant in different macrophyte beds and stony littoral areas, both in heavily polluted and undisturbed sites. The maximum abundance and biomass of G. fasciatus was about 54,000 ind m^–2 and 160 g (wet wt.) m^–2. Negative impacts of G. fasciatus on native species have been observed. Studies are needed to identify the effects of G. fasciatus on the functioning of littoral communities and to predict and control the spread of this amphipod.