A Two Phase Population Survey of Mussels in North Dakota Rivers (SWG T-24-R)

Mussels are one of the most threatened groups of animals in North America. An estimated 71.1% of the North American mussel fauna are endangered, threatened, or of special concern. A recurring theme of many recent mussel surveys is the decline in both abundance and diversity in the native mussel species. Jones et al. (2001) report that mussel species have been reduced from 27 to 18 species in the upper Clinch River in Tazewell County, Virginia. In a study of the Republican and Smoky Hill river basins in northwestern Kansas, Bergman et al. (2000) found that 11 species have been extirpated when compared to the historical fauna. Poole and Downing (2004) examined mussel demographics in Iowa watersheds comparing data from 1984 and 1985 to a resampling effort done in 1998. They found that maximum species richness for a site was reduced from 22 to 15 species and that all mussel species were extirpated from 47% of the reaches sampled. This particular study is troublesome in that it involves rivers and streams in a primarily agricultural area, and states that a large component of the loss in mussels is due to the agricultural practices in the area. Since North Dakota is largely an agricultural state, it is important to document the current status of our mussel populations.