Over the past twenty years, Lake Michigan has undergone changes in community composition, nutrient dynamics, and system productivity due to reduced nutrient loading and the introduction of invasive species (e.g., round goby, Neogobius melanostomus; zebra mussel, Dreissena polymorpha; quagga mussel, Dreissena bugensis). There is uncertainty in about how predatory fish in Lake Michigan will adjust their feeding patterns to the observed changes in forage fish abundance. Previous research efforts have primarily focused on the response of salmonids, there has been much less attention given to the piscivorous burbot (Lota lota), a native species of cod found in the cold, offshore regions of Lake Michigan. We investigated burbot feeding patterns in Lake Michigan using diet data from burbot stomachs collected in 2016 and 2017, as well as fatty acid composition and stable isotope ratios of burbot and round goby collected in 2016. Stomach contents revealed that burbot are primarily consuming round goby throughout Lake Michigan, with small contributions from sculpin (deepwater sculpin, Cottus cognatus; slimy sculpin, Myoxocephalus thompsonii), alewife (Alosa pseudoharengus), and other fish. Similarities between the spatio-temporal patterns of fatty acid compositions and stable isotope ratios in burbot and round goby suggest long-term feeding on round goby by burbot. Prior to the invasion of dreissenid mussels and round goby in Lake Michigan, burbot were known to have a diverse diet which included alewife, sculpin, bloater (Coregonus hoyi), and stickleback (Gasterosteidae spp.); however, it appears that burbot now consume almost exclusively round goby, which will likely have implications for the connection of nearshore and offshore food webs in Lake Michigan.
|Original language||English (US)|
|Title of host publication||Midwest Fish and Wildlife Conference 2019|
|State||Published - 2019|
Leonhardt, B., Turschak, B., Happel, A., Czesny, S., Bootsma, H., Richard, J., & Höök, T. (2019). Investigating Burbot Diets in Lake Michigan Through Stomach Contents, Fatty Acids, and Stable Isotope Ratios. In Midwest Fish and Wildlife Conference 2019