ABSTRACT
ABSTRACT Since the introduction and establishment of dreissenid mussels in the Laurentian Great Lakes of North America in 1986, they have invaded water bodies as far west as Southern California. The more commonly found dreissenid mussel in the southwestern United States is the quagga mussel (Dreissena rostriformis bugensis). Dreissenid mussels are biofoulers notorious for their ecological and economic impacts. The quagga mussel was ‘rst discovered in Lake Mead in January 2007. Because climates and biomes vary from east to west in the United States, thermal tolerance should be determined for dreissenid mussels west of the 100th meridian, where they inhabit warmer water bodies than occur in the northeastern United States. Thermal treatment is an ecologically acceptable approach for control of dreissenid macrofouling (Mackie and Claudi 2010). However, studies of thermal tolerance in dreissenids have focused primarily on populations in the cooler waters of the northeastern United States and particularly on zebra mussels (Dreissena polymorpha). The purpose of this study was to determine whether conditions in the southwestern United States affect the acute upper thermal limits of adult quagga mussels. Adult quagga mussels found in Lake Mead (Nevada) could not survive acute exposure to water temperatures greater than or equal to 30°C, above which survival times declined with increasing temperatures up to 40°C. The results of this study revealed that the upper thermal limits of quagga mussels from Lake Mead were similar to those previously recorded for quagga mussels from the northeastern United States.
A major aspect of aquatic ecology and environmental health is biological invasions by nonindigenous species. Biological invasions can be expensive in terms of eradication and management cost, manpower and resource allocation, alteration of ecosystem processes, and reduction of biological diversity (Vitousek et al. 1996). Two of the most notable nonindigenous species introduced to North American waters in the 1980s were Dreissena polymorpha and Dreissena rostriformis bugensis, commonly known as zebra and
Introduction .............................................................................................................................................. 83 Methods .................................................................................................................................................... 86
