Biochemical data reveal that sea lamprey feed on a variety of species

Despite being an abundant top predator in the Great Lakes, knowledge of sea lamprey feeding ecology remains hindered by methodological constrains. Particularly, our knowledge of sea lamprey diet habits relies on wounding rates of commercially caught fish. Biochemical methods provide means to extract diet information from sea lamprey themselves. Of particular interest is the use of stable isotope and fatty acid data to qualitatively describe foraging patterns of sea lamprey. Adult Sea lamprey were captured throughout the Lake Michigan basin during spring spawning migrations into rivers, and analyzed for both stable isotope ratios and fatty acid profiles. Exploratory multivariate analyses were used to investigate the existence of feeding guilds amongst the captured individuals. In general, we noted a large range in biochemical values suggesting a wide range in host species preferred by individual sea lamprey. Comparing the range of biochemical tracers with published data on host species, we conclude that some sea lamprey likely feed on sucker species while other focus on salmonid and burbot hosts. Thus, sucker and burbot may offer a buffer for sea lamprey, allowing high populations and further obstructing salmonid restoration efforts.