Stable isotope analysis of food web samples from Hudson Bay

Fisheries and Oceans Canada (DFO) is currently involved in research programs that investigates the diets, trophic status, and food web structure of marine mammals, Arctic fish, benthic invertebrates, and zooplankton. In collaboration with the University of Manitoba, biological samples have been collected from the Western and Southeastern Hudson Bay (Churchill, James Bay and Belcher Islands) to determine horizontal and vertical trophic structure from invertebrates (benthos and zooplankton) to fish and marine mammals to determine energy flow within this system. Using stable isotope analysis (d13C, d 15N and d 34S) of numerous species groups species groups (zooplankton, benthos, fishes, and marine mammals), our objectives are to: (1) estimate the trophic structure of these systems. In addition, d13C and d34S analysis across the food web allows the ability to (2) quantify horizontal energy flow (freshwater versus marine energy, pelagic versus benthic energy) throughout these ecosystems. As well, using d34S in a food web perspective has not been wide applied in the Arctic.