Chapter 8: Ecological Factors Affecting the Sustainability of Chinook and Coho Salmon Populations in the Great Lakes, Especially Lake Michigan
Michael J. Hansen and Mark E. Holey
Pacific salmon are exotic species to the Great Lakes, and their abundance has been largely driven by stocking. This leads to a different perspective on their ecology than is true elsewhere in their range (Kocik and Jones 1999). Further, salmon stocking programs have tended to focus on chinook salmon Oncorhynchus tshawytscha and coho salmon Oncorhynchus kisutch. These have led to fisheries largely dependent on these two species. Finally, salmon stocking in the Great Lakes was begun in Lake Michigan, and more salmon have been stocked in Lake Michigan than elsewhere in the Great Lakes basin. As a result, much of the study of salmon ecology has been pursued in Lake Michigan, and more of the salmon story has unfolded there than in the other lakes. For these reasons, we focus our description of salmon ecology (survival, growth, and reproduction) on chinook and coho salmon in Lake Michigan, with comparisons to the other lakes where information is available. We believe that the ecology of chinook and coho salmon in Lake Michigan provides a reasonable example for the rest of the Great Lakes basin that nicely complements the recent review by Kocik and Jones (1999).