Development of Tributary Conservation Priorities for Great Lakes Migratory Fishes in Western Lake Huron

Fish migration between the Great Lakes and its tributaries is critical for maintaining population structure and fisheries production in the Great Lakes, and provides important nutrient transport and other services.  Unfortunately, this process has been highly altered due to migratory barriers and other impacts.  In order to develop effective and efficient conservation strategies to conserve this key process across the full suite of native migratory fish, we need spatially explicit information on which tributaries are the most important.  Unfortunately, there are no large-scale datasets focused on migratory fish monitoring.  We utilized a wide variety of riverine and nearshore fish sampling datasets to see how well we could map migratory fish priorities in the US waters of Lake Huron, based on occurrence frequencies, abundance, young-of-year abundance, Aquatic Gap predictions, and nearshore occurrence frequencies adjacent to the river mouth.  Priority tributary watersheds were identified separately for connected reaches and unconnected (by dams) reaches.  Results were reviewed by regional fish biologists and modifications were made based on their knowledge.  Final maps of priority tributaries were concordant with the maps produced from the analysis, indicating that the original analysis was effective in mapping migratory fish priorities.