Date of Award
The resiliency of our aquatic ecosystems hinges on our ability to protect the native species that reside within them. The river redhorse (Moxostoma carinatum) is one such example and populations have become low enough to warrant listing by the State of Michigan. Causes of decline include overfishing, habitat alteration, and lack of knowledge of basic life-history attributes including their use of non-spawning habitat and spawning locations. In order to understand the river redhorse’s habitat use we implanted 15 individuals with radio transmitters and tracked their locations over the course of a summer. Tagged river redhorse were found to move as far as 50 km down river after spawning and establish themselves in small home ranges between 0.04 and 0.12 km2. The presence of mussels and snails, the river redhorse’s preferred food source, was the primary habitat characteristic selected for by tagged individuals and was documented at 79 percent of all tracked locations. In order to locate the tributaries that the river redhorse use for spawning we developed a species-specific genetic test and used eDNA collection to examine their springtime occurrence in five tributaries of the Grand River. While no tributary samples amplified successfully it is possible to use our test in future studies to identify river redhorse spawning areas and to identify potential river redhorse specimens. The recovery of the river redhorse in the lower Grand River will depend on our ability to protect these newly discovered feeding areas and to ensure an accurate understanding of the river redhorse’s current distribution. Future management should therefore focus on expanding our knowledge of the river redhorse’s distribution, protecting native mussels and snails, and should attempt to maintain migration routes between spawning and summer habitats.
Preville, Nicholas Michael, "Habitat Use and Tributary Occupancy of the Threatened River Redhorse (Moxostoma carinatum) in the Grand River, MI, USA." (2019). Masters Theses. 942.
Available for download on Saturday, August 13, 2022