Thesis (M.S., Natural Resources) -- University of Idaho, 2015 | I tested the efficacy of aqueous solutions of sodium hydroxide, NaOH, and calcium hydroxide, Ca(OH)2, (pH 11-12), to cause mortality in New Zealand mud snails (NZMS - Potamopyrgus antipodarum ), quagga mussels (Dreissena bugensis), and Asian clams (Corbicula fluminea). Static toxicity tests were conducted in freshwater with all three species, and a limited number of trials were conducted in brackish seawater (15 ppt) with quagga mussels. The quagga mussel was most sensitive to elevated pH, followed by the NZMS, and then the Asian clam. Time to mortality was most rapid at warm temperatures compared to cold temperatures, and early life stages were more sensitive than advanced life stages. My results provide strong evidence that elevated pH would be a successful disinfection tool against aquatic invasive mollusks in ballast and bilge water.