CONICET | Buscador de Institutos y Recursos Humanos

Background: In recent decades, invasive quagga mussels have expanded to theWestern United States from the Great Lakes region of North America. Most studiesthat evaluate the invasion potential of quagga mussels in western water bodies haveutilized physiological and life history information from zebra mussels, a relatedtaxon. Few studies have assessed the potential for invasion using specific informationfrom quagga mussel life history or experiments that test for their survival in the freshand saline waters of the western United States.Methods: We investigated quagga mussel survival, growth, and reproduction usingsemi-natural experiments under temperature and light controlled conditions across agradient of water salinity (fresh to brackish) and pH (8.411). Water from Lake Meadwas used as a positive control in our experiment, and water from Pyramid Lake andthe Truckee River was used as brackish and freshwater treatments, respectively.The mussels used in the experiments were collected from Lake Mead.Results: After 12 h in brackish water (4 ppt, pH 9.3), we observed 100% mortality ofadult mussels. The swelling and disintegration of body tissues and high mortalityrates indicated that high potassium, sodium, and chloride concentrations were thelikely causes of death in brackish water treatments. In contrast, mussels were able tosurvive, grow, and reach sexual maturity in freshwater (0.1 ppt) with a low calciumconcentration (17 mg L−1) after 57 days. Mussels died after 2 days at pH 11 and after12 days at pH 10; during the 14-day monitoring period, no mortality was detected atpH 9.0, 9.3, or 9.5 and mussels did not exhibit any visual indications of stress.Understanding quagga mussel physiological and environmental tolerances appearsto be essential for assessing their invasion potential in aquatic habitats.

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