Potential reintroduction of Arctic grayling, Thymallus arcticus, into the West Branch of the Maple River: An assessment of abiotic factors, salmonid diet and community

Abstract

Arctic grayling were once abundant species in northern Michigan that have since been extirpated. Logging, destruction of habitat, overfishing, and introduction of non-native trout species contributed to the decline of the gray ling population in Michigan. Habitat restoration and a recent resurgence of interest and funding for reintroduction of gray ling has led many groups to investigate rivers in Michigan for grayling suitability. In this study, we investigated the west branch of the Maple River, located in Emmet County, Michigan, as a potential site for reintroduction of gray ling. Our study consisted of habitat assessment, macro invertebrate community study, and fish community study. We found that the west branch of the Maple River is a high quality cold-water river with suitable substrate for grayling. Additionally, there are abundant macroinvertebrate prey items for grayling. Grayling would be able to coexist with other fish species such as Brook trout, Salvelinus fontinalis, in some upstream areas due to the to low abundance competitor trout like Brown trout, Salmo trutta, and Rainbow trout, Oncorhynchus mykiss. More studies must be done on other sites, but we have concluded that the reintroduction of grayling into the west branch of the Maple River would be an achievable effort.