First Finding of the Amphipod Echinogammarus ischnus and the Mussel Dreissena bugensis in Lake Michigan

摘要

The first finding of the amphipod Echinogammarus ischnus and the mussel Dreissena bugensis in Lake Michigan is documented. These two species are widespread and abundant in the lower lakes, but had not yet been reported from Lake Michigan. E. Ischnus is generally considered a warm- water form that is typically associated with hard substrates and Dreissena clusters in the nearshore zone. Along the eastern shoreline of Lake Michigan, this species was present at rocky, breakwall habitats along The entire north-south axis of the lake.