Predation on walleyes Sander vitreus by Double-crested Cormorants Phalacrocorax auritus at the West Sister Island colony in 2005

Double-crested Cormorants Phalacrocorax auritus (hereafter cormorants) first nested in Lake Erie in the mid 1900s and have established numerous successful nesting colonies. Concerns by commercial and recreational fishermen about potential negative effects of this piscivorous species on populations of fishes in Lake Erie, especially walleyes Sander vitreus, prompted us to conduct two pilot investigations of consumption of walleyes by cormorants.

Patrick M. Kocovsky, Martin A. Stapanian, William H. Edwards, and Jason M. Jones, U.S. Geological Survey, Great Lakes Science Center