Analysis of Freshwater Mussels (Unionidae) at Specific Sites in Pool 5 and Lake Pepin, Upper Mississippi River, 1994.
ARMY ENGINEER WATERWAYS EXPERIMENT STATION VICKSBURG MS ENVIRONMENTAL LAB
Pagination or Media Count:
In July 1994, freshwater mussels were collected using qualitative and quantitative 0.25 sq m total substratum methods at the following locations in the upper Mississippi River UMR directly on and between two wingdams at river mile RM 741.6 in Pool 5, Lake Pepin RM 776.8, and an area immediately downriver of Lake Pepin RM 764.4. The purpose was to document density, species diversity, species richness, community composition of native mussels, and density and percent abundance of the recently introduced nonindigenous zebra mussel, Dreissena polymorpha. Between wingdmns in Pool 5, total density was 10.0 individualsm2 and a total of eight species were collected. The fauna was dominated by A. p. plicata and Quadrula p. pustulosa. Moderate-to-good evidence of recent recruitment was indicated by the fact that 12 percent of the individuals and 50 percent of the species were less than 30 mm in total shell length. Using a suction dredge, a total of 223 individuals and 12 species of native mussels were collected in 20 samples on a wingdam. The fauna was dominated by A. p. plicata, which comprised 60 percent of the fauna and was collected in 100 percent of the samples. There was evidence of recent recruitment 8.4 percent of the individuals and 36.4 percent of the species were less than 30 mm in total shell length. In Lake Pepin, total density of native mussels was 2.4 individualsm2 at a depth of 10 ft and 6.3 individualsm2 at a depth of 5 ft. Evidence of recent recruitment was good at both water depths 22 to 25 percent of the individuals and 50 to 71 percent of the species were less than 30 mm in total shell length. Density in the reach immediately downriver of Lake Pepin was 19.6 individualsm2, which was significantly greater p 0.05 than in the lake. At this location, 19 percent of the individuals and 50 percent of the species showed evidence of re
- Hydrology, Limnology and Potamology