Long-Term Decline in Freshwater Mussels (Bivalvia: Unionidae) of the Western Basin of Lake Erie

Authors

Thomas F. Nalepa, Great Lakes Environmental Research LaboratoryFollow
Bruce A. Manny, National Fisheries Research Center-Great Lakes
James C. Roth, University of California - Berkeley
Samuel C. Mozley, North Carolina State University at Raleigh
Donald W. Schloesser, National Fisheries Research Center-Great Lakes

Date of this Version

1991

Citation

Published in J. Great Lakes Res. 17(2):214-219.

Abstract

Long-term trends in the abundance of unionids in the western basin of Lake Erie were examined from data collected at 17 stations in 1961, 1972, and 1982. The mean number of unionids at these stations declined over this time period, decreasing from 10 m^-2 in 1961, to 6 m^-2 in 1972, down to 4 m^-2 in 1982. This decline in abundance was reflected in the decrease in the number of stations where mussels were found; unionids were found at 16 of the 17 stations in 1961, but at only 6 stations in 1982. Reasons for the decrease in the unionid population are not generally apparent, but are probably related to the decline in water quality and periods of low oxygen levels over the time period of the surveys.