An assessment of the health and historical changes of the nearshore fish community of the St. Marys River

Abstract

We examined the nearshore fish community in the St. Marys River using a standardized boat electrofishing protocol to (1) compare the current nearshore fish community of the river to previous surveys, (2) compare the status of fish communities from four distinct areas of the river (the upper river above the compensating gates, the main river, Lake George, and the lower river), and (3) complete an overall assessment of the fish community using an index of biotic integrity approach. The St. Marys River contains a diverse and complex fish community, with dissimilar fish communities located in broad habitat types along the spatial extent of the river. We demonstrated that the nearshore fish community is relatively unaltered over the past 25 years, with many species that were common in the early 1980s remaining important community members today. More invasive fishes now inhabit the river, but unlike many other areas of the Great Lakes, invasives are not common and do not appear to be negatively affecting native species. The overall health of the St. Marys River fish community compared favorably with relatively un-impacted sites from Lake Huron.