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Payne, B. S. and A. C. Miller (1992). Mussel surveys at potential mooring sites for barge tows near Upper Mississippi River Locks and Dams 9 and 10. U.S. Army Corps of Engineers, Miscellaneous Papers of the U.S. Army Corps of Engineers Waterways Experimental Station WES/MP/EL-92-11.

In September 1990, a survey was conducted of 10 potential mooring sites for barges along the edge of the navigation channel just above below Locks and Dams 9 and 10. In general, conditions were too erosional just below and too depositional just above the locks and dams to support substantial populations of mussels. The only substantial community found was at a site designated as A3, at river mile 649.2 to 649.5 above Lock and Dam 9. Nineteen species of unionids were represented among 629 individuals collected at this location. A low-density assemblage (2 to 11 individuals/m²) occurred at the upper and lower ends of Site A3. The endangered species Lampsilis higginsii comprised approximately 0.3 percent of the mussel community at Site A3. The estimated density of L. higginsii equaled 0.02 individual/m². This density value was slightly less than the range of densities (0.04 to 0.23 individual/m²) that have been estimated for the least dense populations of species that have persisted in several other large-river mussel beds. Thus, the density of the L. higginsii population at Site A3 may be slightly less than the minimum required for a reproductively viable population.