Is solar radiation responsible for declines in marine survival rates of anadromous salmonids that rear in small streams?

• Published in: Canadian Journal of Fisheries and Aquatic Sciences
• Main Authors: Walters, Carl, Ward, Bruce
• Format: Article in Journal/Newspaper
• Language: English
• Published: Canadian Science Publishing 1998
• Subjects: Aquatic Science; Ecology, Evolution, Behavior and Systematics; Atlantic salmon; Salmo salar
• Online Access: http://dx.doi.org/10.1139/f98-203; http://www.nrcresearchpress.com/doi/pdf/10.1139/f98-203

There have been profound declines in marine survival rates of steelhead trout (Oncorhynchus mykiss), coho salmon (O. kisutch), chinook salmon (O. tschawytscha), and Atlantic salmon (Salmo salar) since the mid-1980s, and these declines have been particularly acute in sunny regions. We suggest that the problem may originate in freshwater with radiation (e.g., UV-B) damage to metabolic machinery that is expressed during stressful periods of smolting and ocean entry and that progressively worse damage may soon appear as reduction in freshwater survivals as well. This hypothesis can be tested quickly by management agencies by comparing survival rates of hatchery-reared fish with and without radiation protection during rearing.