1. Fish Ecology and Conservation Physiology Laboratory; Department of Biology and Institute of Environmental Science; Carleton University; 1125 Colonel By Drive Ottawa Ontario K1S 5B6 Canada
2. Pacific Salmon Ecology and Conservation Laboratory; Department of Forest and Conservation Sciences; University of British Columbia; 2424 Main Mall Vancouver British Columbia V6T 1Z4 Canada
3. Department of Ecology, Evolution and Marine Biology; University of California; Santa Barbara California 93106-9620 USA
4. Fisheries and Oceans Canada; Science Branch; Pacific Region; Cooperative Resource Management Institute; School of Resource and Environmental Management; Simon Fraser University; Burnaby British Columbia V5A 1S6 Canada