BIOL 1070 Study Guide - Midterm Guide: Ballast Tank, Zebra Mussel, Habitat Destruction
22 Dec 2015
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Zebra mussels, a bivalve mollusc endemic to europe, has established a population in lake st clair and erie, likely as a result of ballast water discharge. Ballast water is added when ship is empty to improve stability. The species appear to become a dominant member of the shallow water benthos throughout the lower great lakes. Its rapid population expansion has been linked both to its possession of free swimming veliger larva and to its fecundity (>30 000 per female). D. polymorpha often causes significant economic losses by obstructing the flow in the intake channels of the hydroelectric installations and water distribution systems. The location for attachment was clearly non-random with dreissena restricted to those portions of the shell which ordinarily protrude above the sediment surface. Shells of dead mussels were less attractive as settlement sites for dreissena than those of live mussels.
