Reduced Survival and Fitness in Native Bivalves in Response to Fouling by the Introduced Zebra Mussel (Dreissena polymorpha) in Western Lake Erie

Abstract

Fouling by the recently established zebra mussel (Dreissena polymorpha) causes differential effects among bivalve communities. In 3-mo experiments and surveys conducted in western Lake Erie during 1990, two native bivalves, Lampsilis radiata and Amblema plicata, showed consistent differences in mortality and biochemical indices of fitness in response to fouling by D. polymorpha. Lampsilis radiata was very sensitive to fouling, experiencing high mortality and reduced fitness in experiments and natural populations. In field experiments, female L. radiata suffered higher mortality and lower fitness than males. Amblema plicata was less sensitive to fouling; fitness was reduced in experimentally fouled A. plicata, but mortality and fitness in natural populations were not affected by D. polymorpha. Six species of native bivalves showed marked differences in mortality rates at three sites surveyed in western Lake Erie. Mortality was higher in the subfamilies Anodontinae and Lampsilinae (including L. radiata) than in Ambleminae (including A. plicata) at all three sites, suggesting that differences in life history strategy and shell morphology among subfamilies may be responsible for differential responses to fouling. These data suggest that fouling by D. polymorpha will result in profound changes in native bivalve community structure.