Wanted: Your Killer Whale Sightings
INTRO: For the past decade, scientists have searched for the cause of the dramatic decline of Steller sea lions in Alaska. Now they're focusing on the role of killer whales. But with so little known about these cunning ocean predators, scientists are asking the public for help. Doug Schneider has more, in this week's Arctic Science Journeys Radio.
STORY: Scientists have studied almost every possible cause for the disappearance of nearly 80 percent of the endangered Steller sea lions that inhabit the Aleutian Islands and western Gulf of Alaska. And while some sort of problem with their food supply remains high on the list of suspects, researchers now are turning their attention to orcas, more commonly known as killer whales. Andrew Trites is a sea lion researcher at the University of British Columbia and director of the North Pacific Universities Marine Mammal Consortium in Vancouver.
TRITES: "We've spent ten years now looking very hard at the question of what could have caused the decline of Steller sea lions. I'd say most researchers agree that it's unlikely to be a single cause. It's probably a combination. The question then is what could be the most significant impact? In terms of mortality, we have not seen animals starving to death. There have been some indications of nutritional stress. But we come back to the issue of what might be ultimately killing these animals. Predators, we know, in many systems are one of the ultimate forms of death, and they could well be playing a significant role in the decline of Steller sea lions and their lack of recovery."
In research published in the journal Science, University of California scientist Jim Estes says predation by only a handful of killer whales could account for the sea lion decline. What's more, continued predation by orcas could be keeping sea lion numbers from recovering. Andrew Trites says he'd like to either prove or disprove Estes' theory, but no one really knows just how many killer whales are out there, especially in the remote western waters where sea lions are declining. And since it's too expensive to conduct an intensive survey on his own, he's asking for help from the public. During a three-day period this month—from July 19 through the 21st—he's asking Alaska boaters to report killer whales they happen to see.
TRITES: "We'd like to know where they went on that day, where they saw the whales, and what they saw the whales doing. If they can give us an idea of the number of whales and if they can differentiate the males from females or younger animals, if they saw them eating anything, that is the kind of information we're looking for."
Trites believes sightings of killer whales during this period could be valuable to researchers trying to learn more about how orcas may be affecting sea lions.
TRITES: "What we're trying to do with this survey is—given that we can't as researchers cover all areas of the Aleutians and Gulf of Alaska—we're counting on those people who are out on the water to give us a heads-up in terms of where they've been and where they've seen killer whales. That will help us in a couple of ways. One will be to help us focus our research efforts: If there are hot spots of whale activity, then we know where to send researchers for more intensive observations. And we're hoping also to come away with a minimum estimate of the abundance of killer whales in Alaska."
OUTRO: The Marine Mammal Consortium has set up a web site for people to report their killer whale sightings. You can visit the site at http://www.alaskakillerwhales.org. 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 (sidebar at top right)
Thanks to the following individual for help preparing this script:
Andrew W. Trites, Ph.D., Director
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. The shortcut to our ASJ news home page is www.asjnews.org.
URL for this page is http://seagrant.uaf.edu/news/
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Questions or comments about the killer whale survey? (email link)
Video courtesy Chris Stark, aboard the R/V Alpha Helix, in Alaska's Aleutian Islands, June 2001
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