Constructing the Nearshore Lake Michigan Food Web Using Multiple Trophic Indicators
Recently, the food webs of Lake Michigan and other Laurentian Great Lakes have been altered by non-indigenous species. These alterations are most evident in the nearshore zone, where hard substratum is covered by the invasive quagga mussel, the round goby is the dominant fish species, and excessive growth of the green, filamentous alga, Cladophora sp., exacerbates water quality problems and results in huge economic losses. The goal of this research program, which is being conducted in collaboration with scientists at the Illinois Natural History Survey and Purdue University, is to define nearshore trophic structure in Lake Michigan, determine how this structure may vary with location, and assess whether it has altered the lake’s carrying capacity for fish in upper trophic levels. We are using a multi-faceted approach that includes conventional diet analysis, stable carbon and nitrogen isotope measurements, and fatty acid profiles.