DNA-BASED IDENTIFICATION OF MUSSELS FROM GRAND SABLE LAKE, MI

Jordan B. Eckstein, Macalester College
Sarah L. Boyer, Macalester College
Mark C. Hove, Macalester College

Freshwater mussels are a very important part of river, lake, and other freshwater ecosystems. Unfortunately, many species of North American freshwater mussels are threatened, and populations are declining. Some mussel populations in Grand Sable Lake (GSL) in Michigan are in danger of extirpation, thus a study has been undertaken to understand why the mussel populations are struggling, with special concern for the Elliptio species. There are many reasons for the endangerment of freshwater mussels, but one aspect that is especially important for conservation is their relationship with their host fish, which they parasitize in the larval stage of life. Yellow perch is a known host fish for the GSL species; however the yellow perch population in GSL is also in decline. By collecting juvenile mussels off naturally infested yellow perch, it is possible to identify which mussels are using the fish as hosts, and therefore gain a better understanding of the current situation in GSL. In this study, juvenile mussels were collected from GSL yellow perch and identified via DNA barcoding. In DNA barcoding, a common gene is sequenced from each individual in order to be compared with known sequences from various mussel species. This allows each juvenile to be assigned a species identity. Phylogenetic analysis of the sequences revealed that Lampsilis siliquoidea and Pyganodon grandis are the two main species using yellow perch, while no Elliptio mussels were found. A possible explanation for this is that the growing trout population has pushed the yellow perch out of certain habitats in the lake, therefore making the perch inaccessible to Elliptio mussels. A number of unidentifiable lampsiline sequences were also produced from juveniles found on the perch, and it is still unclear what these mussels might be. Further studies should aim to include juveniles collected over a wider time frame in order to gain a comprehensive sampling of the mussels that may be parasitizing yellow perch.