1. Canadian Rivers Institute, Department of Biology, University of New Brunswick, Post Office Box 4400, Fredericton, New Brunswick E3B 5A3, Canada
2. Canadian Rivers Institute, Department of Biology, Faculty of Forestry and Environmental Management, University of New Brunswick, Post Office Box 4400, Fredericton, New Brunswick E3B 5A3, Canada
3. Department of Biology, Acadia University, 33 Westwood Avenue, Wolfville, Nova Scotia B4P 2R6, Canada