 Radio Script 2001 __________________ Salmon May Move North
INTRO: Last summer, residents of Alaska's Arctic Ocean coast reported seeing migrating salmon, something that no one can remember ever having seen that far north before. But as Doug Schneider reports in this week's Arctic Science Journeys Radio, scientists say a warmer climate may force salmon to look for colder water far from where they are today.
STORY: When Canadian researcher David Welch began studying salmon survival in the North Pacific Ocean, he expected to find salmon throughout the sea. But the further south he went, the warmer the ocean became—and the fewer salmon he found. As he moved into waters roughly the same latitude as northern California, he didn't find any salmon at all. WELCH: "We've got about 21,000 days of fishing at sea over a 40-year period. For every species of salmon, they get to a certain temperature and they just stop. We've almost never caught a salmon south of those temperatures in warmer waters." If salmon are that sensitive to temperature, Welch wondered, what would happen to salmon if current models about how the global climate might warm actually came to pass? Under those models, the amount of the greenhouse gas—carbon dioxide—in the earth's atmosphere is expected to double during the next 50 years. That in turn would cause the North Pacific Ocean to warm by as much as six degrees Fahrenheit. If the models prove correct, Welch says the colder water that salmon prefer would no longer be found in the North Pacific. WELCH: "We found that the temperatures didn't even exist in the Pacific Ocean. They were up in the Bering Sea. That would mean everybody's salmon—Canadian, Alaskan, Washington, Oregon, Japanese, and Russian—might not be in the Pacific Ocean at all for much of their life span." Of course, Welch's predictions depend to a great extent on just how much the North Pacific Ocean actually warms up. Scientists caution that the models used to predict climate change aren't perfect. Still, scientists generally agree that David Welch is on to something. Milo Adkison is a fisheries professor at the University of Alaska Fairbanks. ADKISON: "This scenario is plausible and very worrying. The reason it's worrisome is that if you get global warming, then the habitat disappears. We could lose large populations of salmon." But don't look for salmon to change their migration patterns overnight. Welch says warming of the ocean will be a gradual event, and that salmon will probably return to their traditional spawning grounds for many years to come. But he says fishery managers need to understand and consider how a changing ocean will affect salmon populations.
OUTRO: This is Arctic Science Journeys Radio, a production of the Alaska Sea Grant Program and the University of Alaska Fairbanks. I'm Doug Schneider. Audio version and related Web sites Thanks to the following individuals for help preparing this script:
Dr. David Welch
Dr. Milo Adkison Arctic Science Journeys is a radio service highlighting science, culture, and the environment of the circumpolar north. Produced by the Alaska Sea Grant College Program and the University of Alaska Fairbanks.
Alaska Sea Grant In the News The URL for
this page is http://seagrant.uaf.edu/news/ |
Listen to story on RealAudio Related Web sites Global climate change: Fisheries Sockeye distribution under current and future climates (map) |