Fish Distributions and Habitat Associations in Manistee River, Michigan, Tributaries: Implications for Arctic Grayling Restoration

Abstract Restoration and enhancement of North American native freshwater fishes have for several decades been the subject of growing interest among fisheries biologists, natural resource managers, non-governmental organizations, and the sportfishing public. The Little River Band of Ottawa Indians (LRBOI) and the Michigan Department of Natural Resources (MDNR), along with universities and public interest groups, are re-examining the potential for re-introduction of the Arctic Grayling Thymallus arcticus, a species that has been extirpated in Michigan since the 1930s. The Manistee River, Michigan, flows through the LRBOI's reservation and once supported the last known native Arctic Grayling population in the state's Lower Peninsula. The objectives of this study were to (1) identify potential biotic limitations, such as competition and/or predation from other fish species, that may interfere with Arctic Grayling re-introduction in the Manistee River watershed; and (2) describe how instream habitat features currently relate to populations of potentially interacting species. Field surveys conducted during June–August 2012 in eight Manistee River tributaries identified suitable abiotic habitat for Arctic Grayling in 20 of 22 sampling reaches. However, high densities of Brown Trout Salmo trutta (a nonnative salmonid) may have influenced some of the habitat associations observed for Brook Trout Salvelinus fontinalis and Slimy Sculpin Cottus cognatus, two species that currently and historically co-occurred in Arctic Grayling habitats. These two species were the most abundant in river reaches with Brown Trout densities less than 0.10 fish/m2. Based on habitat conditions and Brown Trout densities, there appear to be four distinct tributary regions for which management strategies could be developed to enhance the success of Arctic Grayling re-introduction efforts. Re-introduction of Arctic Grayling in the Manistee River watershed would support LRBOI and MDNR goals for native species restoration and would provide a unique and historic angling opportunity that has been absent in Michigan for nearly 100 years.