1. Institute of Ocean Sciences, Fisheries and Oceans Canada, P.O. Box 6000, 9860 West Saanich Road, Sidney, British Columbia V8L 4B2, Canada, School of Earth and Ocean Sciences, University of Victoria, Victoria, British Columbia V8W 3P6, Canada, and Raincoast Conservation Society, P.O. Box 8663, Victoria, British Columbia V8W 3S2, Canada