Spawning Black Bass and the Invasive Round Goby in Lake Ontario and the St. Lawrence River
This thesis examined the relationships between the invasive Round Goby (Neogobius melanostomus) and the economically important recreational fish species, Smallmouth Bass (Micropterus dolomieu) and Largemouth Bass (Micropterus salmoides). Nesting bass were located in Lake Ontario and the St. Lawrence River prior to the opening of the angling season in 2015. Predator density, offspring development, and predation intensity during simulated catch-and-release angling were measured to determine the risk of combined negative effects from recreational angling and nest predation by Round Gobies. General linear models were used to compared the influence of habitat, temperature and species on each variable. As previously demonstrated, Round Gobies preyed on Smallmouth Bass eggs and larvae when the guarding male was absent from the nest. Largemouth Bass nests were located in areas with very low Round Goby abundance and are likely not experiencing significant predation by Round Gobies. Smallmouth Bass nesting near Lake Ontario are at the highest risk for predation because of slower offspring development in colder water, and prevalent rocky/sandy nesting habitat with high Round Goby abundance. The closed fishing season in 2015 did not protect the majority of Smallmouth Bass from recreational angling over the vulnerable stage of offspring development. Smallmouth Bass recruitment might be limited in these areas from a combination of hyper abundant predators and recreational angling.