摘要：Currently, few data exist for the mussel assemblages of the Tyronza River, Arkansas. The goal of this project was to inventory the freshwater mussel assemblages of the Tyronza River and determine the status of the federally endangered Potamilus capax. We qualitatively and quantitatively sampled mussel assemblages and documented the occurrence of S1 (extremely rare), S2 (very rare), and S3 (rare to uncommon) species. A total of 70.4 river kilometers were sampled in 2006 and 2007 resulting in 363 sampling sites, 4030 live individuals, and 25 species. We observed a total of 1 S1, 2 S2, and 9 S3 species. Mean catch-per-unit-of-effort was 0.9 (1.2 SD) individuals / min. and mean species richness and individual abundance were 3.4 (2.7 SD) species / site and 11.1 (15.1 SD) individuals / site, respectively. Thirteen Potamilus capax were collected during this survey, with only 1 gravid female and 2 juveniles. Quantitative survey mean densities per site ranged from 1.0 to 1.9 mussels / m2 with an overall mean of 1.4 individuals / m2 (0.3 SD). A total of 7 Potamilus capax were observed during quantitative sampling. Community Numerical Standing Crop estimates ranged from 70 ± 30 to 22,986 ± 7,905 individuals. The data collected from this survey provide a valuable baseline on the mussel assemblages of an altered-alluvial river and the location and status of all S1, S2 and S3 species. This information is essential to the management of this imperiled fauna in the Tyronza River.
