Asian clama

From Great Lakes Wiki

The Asian clama or The purple varnish clam, is new to The Great Lakes. Little is known about this species but for those trying to make a meal out this shellfish beware, the Asian Clama tested positive for Paralytic Shellfish Posion {PSP}. The clam has a brown outer coat and usually a purple inside, and was introduced to The Great Lakes through ballast water. These species are also harmful to water intake systems.

Picture and Information sited from: Mills, C.E. 1999-present. Nuttallia obscurata, the purple varnish clam or the purple mahogany-clam