Analysis of four Maple River sites for proposed reintroduction of Thymallus arcticus

Abstract

The historically abundant Arctic Grayling (Thymallus arcticus) is a native Michigan Salmonid was extirpated due to many abiotic and biotic factors. Renewed interest in reintroducing T arcticus to Northern Michigan Rivers by the DNR led to an investigation of viability on four sites of the Maple River in Emmett County, Michigan. We evaluated the abiotic factors and components of Salmonid competition to assess if T arcticus reintroduction could be viable. Analysis of temperature, substrate, macroinvertebrates, fish communities and diet showed that suitable habitat characteristics were present in the two West Branch sites of the Maple River. In these two sites, there was ample preferred food sources, lower percentages of non-native Salmonids and suitable substrate compositions. While two sites were deemed viable, removal of a Dam on the Maple River may change river composition. Thus, more research is needed on fish communities, diet, and competition post-Dam removal to determine if T arcticus should be reintroduced.