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Evidence of global warming's effects on aquatic environments is already abundant. In California, scientists have documented a 4 degree Fahrenheit rise in water temperatures in Monterey Bay that coincides with a massive northward shift of entire populations of sea life. In Alaska, the decline of pollock and other fish populations has been linked to warming temperatures, as have erratic shifts in salmon runs. Warming ocean temperatures around Antarctica have shrunk ice cover and caused major damage to populations of krill, a small shrimp-like crustacean. Krill is the base of the food chain in Antarctica and is vital to the survival of penguins and whales, as well as numerous fish and sea birds. Coral bleaching due to global warming is the most serious threat to coral reefs. Rising water temperatures heat the coral, breaking down the complex biological system that coral have evolved to survive. In some places, water temperatures are nearing the coral's heat tolerance. Already, 27 percent of the world's reefs have died, and by 2020, temperatures could rise enough to destroy most of the world's remaining coral reefs. Up to Top HOME | Email Signup | About Us | Contact Us | Terms of Use | © 2008 Sierra Club |
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As the earth continues to warm over the next 100 years, the temperatures of streams, rivers, lakes and even oceans will rise. For many fish species, this could spell disaster.
Trout and salmon need cool waters to survive. A study by the Environmental Protection Agency found that a 5 degree Fahrenheit rise in average temperatures over coming decades could devastate trout and salmon populations throughout the United States. Connecticut, Indiana, Maine, Massachusetts, Ohio and Rhode Island could lose their entire rainbow trout populations. In addition, effects of global warming could force the salmon to abandon the British Columbia coast as well as the Gulf of Alaska. Brook trout could vanish entirely from Massachusetts, Michigan, New Hampshire, New York, Pennsylvania, Utah, Vermont, Virginia and Wisconsin.
Threatened salmon populations in the West and Northwest could be hit hard. Not only could warming rivers and streams threaten their ability to reproduce, but rising ocean temperatures may shift currents. This could deny salmon the food they need and leave them vulnerable to predation by exotic southern fish species during the period of their life spent at sea.