Feeding Ecology of the Round Goby (Neogobius melanostomus- Pallas, 1814) in Two Contrasting Environments: Eastern Lake Erie and a Fourth Order Stream

I assessed the feeding ecology of the round goby in eastern Lake Erie and a recently invaded stream (Ellicott Creek). My objectives were: 1) to compare the length-weight relationship and condition of round gobies in eastern Lake Erie and Ellicott Creek, 2) to evaluate the δ15N and δ13C content of the food web of round gobies in the lake and the creek, and 3) to compare the trophic position of round gobies in the two different environments. Round gobies in eastern Lake Erie had positive allometric growth and were more rotund than round gobies in the creek, which had isometric growth. Round gobies in the lake were more enriched in δ13C than round gobies in the creek, an indication that the C-source that fuels each food web is different. In the lake, there were variations in the δ15N content of the round gobies depending on their size, whereas the δ15N content of the round gobies in the creek was similar for all fish sizes. However, the overall δ15N content of round gobies in the lake and the stream were not statistically different. In general, the trophic position of round gobies in eastern Lake Erie was higher than that of round gobies in Ellicott Creek. I conclude that round gobies in the tributary streams of the Great Lakes are still expanding their range and have the potential to severely alter stream ecosystems. Round gobies in the lake are well established and play a vital role in the lake food web