Diporeia - This shrimp-like organism lives in the sediments of all the Great Lakes and ranges in size from 1 to 10 mm. They are a good source of food for whitefish and other fish during the early stages of their lives. Currently their populations are declining in all of the Great Lakes except Lake Superior and the deep portions of Lake Michigan.

Rusty Crayfish - Rusty crayfish resemble lobsters, having a thick, bony plated exoskeleton with oversized claws. Rusty crayfish are big eaters and feast on aquatic plants, insects, fish eggs, and small fish. A native of the Ohio River Basin, it is considered a threat to Michigan's native crayfish population, and could have a severe impact on the ecosystem. The major threat concerns the reduction of aquatic plants and the species that live in these communities. Many fish may lose nesting areas and shelter if aquatic plant beds are reduced due to the presence of the rusty crayfish.