ABSTRACT

About 179 native fish species occur in the Great Lakes. This level of species diversity is modest compared to other regions in the world, but Great Lakes fishes are important ecological resources in the world's largest freshwater ecosystem. The fish faunal biodiversity of the Great Lakes region faces many threats, including invasive species, eutrophication, climate change, habitat loss, and degradation. This chapter focuses on the influences of dams on fish diversity in the Basin. Fragmentation affects species, such as lake sturgeon, that migrate from the Great Lakes to spawn in streams, as well as species that reside primarily in streams but move seasonally for spawning, such as brook trout. To date, the impacts of climate change are only beginning to manifest themselves, and as such, the projected impact on the fish diversity of the Great Lakes depends critically on the types and extent of changes in the climate regime that actually occur.