Hart, R.A. 1995. Mussel (Bivalvia: Unionidae) habitat suitability criteria for the Otter Tail River, Minnesota. M.S. Thesis, North Dakota State University. 60+ pp.
Habitat suitability data for 4851 mussels, representing 13 species, were collected from sample sites on the Otter Tail River, MN. Habitat suitability criteria were developed for seven species of unionid mussels. Amblema plicata, Fusconaia flava, Lasmigona costata, and Strophitus undulatus all had similar preferences for velocity, depth, substrate, and cover. Velocities most preferred were about 80 cm/s with velocities < 25 cm/s having no suitability. Depths of 150 cm were the most preferred; depths < 60 cm had no suitability. These four mussel species were found most often in gravelly substrates with no instream cover. Amblema plicata, Fusconaia flava, Lasmigona costata, and Strophitus undulatus were found most often in the run habitats. Habitats most suitable for Anodonta grandis were slow moving (<10 cm/s), deep waters (135 cm) where aquatic vegetation was present. Headwater sites had lower mussel density and the least amount of species than did the downstream sites. Changes in density and species composition may be lack of suitable habitat, low stream flows in the upstream reaches, or downstream dams blocking the passage of glochidia-infected fish. The habitat suitability criteria developed in this study may aid in the establishment of protected stream flows, preserving the run habitats most suitable for the mussels residing in the Otter Tail River.