Potential reintroduction of Arctic grayling in Michigan's lower peninsula: a study of biotic factors in the Maple River

Abstract

Arctic grayling (Thymallus arcticus) were once one of the most abundant salmonids in the northern Lower Peninsula of Michigan but were extirpated entirely from Michigan by the early 1900s due to overfishing, the introduction of non-native salmonids, and the logging industry. In recent history, an interest to reintroduce Arctic grayling back into Michigan has developed and multiple groups have begun studies to see suitability of Michigan streams and rivers for gray ling. We performed an abiotic and biotic assessment of the West Branch Maple River in Emmet County, Michigan for potential grayling reintroduction. We found water temperatures to be within a suitable range and substrate within the river to be that preferred by grayling. Low abundance of competitive brown trout and high abundance of preferred prey of grayling also showed the viability of the West Branch Maple River for gray ling. The results of this study show that the West Branch Maple River should be considered for the reintroduction of grayling but further, more extensive, studies of the river are needed to make sure of this. The removal of the Maple River Dam also presents an interesting case of a change in the Maple River that will also require further studies.