EFFECTS OF THE EXOTIC BIVALVE CORBICULA FLUMINEA ON A NATIVE BIVALVE ELLIPTIO COMPLANATA

Abstract

In order to establish that native freshwater mussel species are threatened by introduced freshwater species, environmental and behavioral factors must be taken into account. Exotic bivalves may deplete dissolved oxygen and sediment organic matter in the stream benthos to such a degree that the habitat becomes unsuitable for native bivalves. This would then alter the native bivalves' behavior, causing them to respond to environmental disturbances with behaviors interpreted as stress in the presence of non-native bivalves. The native bivalve, Elliptio complanata, displayed behaviors associated with environmental stress in response to oxygen and nutrient depletion by the introduced bivalve, Corbicula fluminea, in a controlled environment. This study clearly shows an increase in movement and mortality of native bivalves in the presence of non-native bivalves. These results indicate that conservation efforts are necessary to ensure survival of native bivalves in freshwater ecosystems.