Fatty Acid Signatures Aid in Assessing Food Web Interactions in Lake Ontario

Fatty acid signatures (FAS) are currently used in food web studies to assess trophic interactions between predator and prey. If we are able to distinguish differences in the FAS of major prey fish in Lake Ontario, we can use these FAS to assess feeding habits of top predators. In this study, three major prey fish (alewife, rainbow smelt, and round goby) were collected at three sites along the south shore of Lake Ontario (Olcott, Rochester, and Oswego) during the spring and fall of 2013. Major predator species (including lake trout, brown trout, Chinook salmon , and Coho salmon) were collected along the south shore of Lake Ontario during the summer of 2013. Using multivariate statistics, FAS were compared among all predator and prey species as well as among location and between seasons for prey fish. Differences in FAS among prey species were greater than any spatio-temporal differences detected. FAS among predator species were also significantly different. Our results demonstrate the applicability of FAS as a tool for assessing predator feeding habits and provide needed FAS data for species of interest in Lake Ontario.