• Spatial and temporal variability of fish and mussel distributions revealed through eDNA metabarcoding

      Dokai, William; McPhee, Megan; Larson, Wesley; Tallmon, David; Zanatta, David (2022-05)
      Unionid mussels (order Unionida) are freshwater bivalves distributed worldwide and are among the world's most endangered taxonomic groups. Unionid mussels utilize various fish species as obligate hosts for their parasitic larval stage, and as a result, native fish species are vital to unionid persistence. One of the primary conservation needs for both unionids and fishes is more complete distributional data. However, these data are labor and resource intensive to collect using traditional survey methods. Here, we utilized an eDNA metabarcoding approach to detect unionid mussels and fishes within a large portion of the lower peninsula of Michigan, USA, with the goal of validating this method for the paired detection of these two groups of taxa. We investigated whether communities of fishes and mussels varied between the tributaries of Lake Michigan and the Grand River watershed, between early- and late-summer sampling events, and between areas of high and low mussel diversity. We detected 21 unique mussel taxa and 46 unique fish taxa within the Grand River watershed and 20 Lake Michigan tributaries. We detected differences in fish and mussel communities across different sampling regions and between sampling events. We also found fish taxa associated with areas of high and low mussel diversity. Notably, we detected more mussel taxa within the Grand River watershed compared to Lake Michigan tributaries, more fish in the August sampling event compared to June, three fish taxa more frequently at areas of high mussel diversity, and four fish taxa more frequently at areas of low mussel diversity. This study demonstrates the utility of combining unionid and fish metabarcoding primers to efficiently describe the co-distribution of these interdependent taxa within the Great Lakes region.