| The fish community of Lake Superior has undergone substantial changes caused by species introductions, overfishing, and depredation by sea lamprey (Petromyzon marinus). The rehabilitation potential of native fishes is linked to their role in the Lake Superior food web, and thus food web ecology must be understood to meet fisheries management goals. I used stable isotope analysis and bioenergetics modeling to answer the following questions about the Lake Superior pelagic community: (1) What is the structure of its food web? (2) Do exotic piscivores constrain the rehabilitation of native lean lake trout (Salvelinus namaycush) through trophic overlap? (3) Do siscowet lake trout constrain the rehabilitation of lean lake trout through trophic overlap? (4) How much sea lamprey production derives from lake trout, and how much derives from other host species? Stable isotope analysis revealed that shallow- and deep-water food webs, with distinct δ13C signatures, exist in western Lake Superior, and further implied little trophic overlap between exotic Pacific salmon ( Oncorhynchus spp.) and native lake trout. |
