Gray Whale Comeback
Don't have RealAudio player? Download free software.
INTRO: Last year, hundreds of emaciated gray whales washed onto beaches from Alaska to Mexico. At the time, scientists blamed food shortages in waters off Alaska, where the whales congregate each summer to feed before migrating south to California and Mexico. But as Doug Schneider reports in this week's Arctic Science Journeys Radio, federal scientists now say the strandings areironicallypart of the species' successful recovery.
DEMASTER: "Pretty much gave it a clean bill of health except for this rather large scale stranding event that occurred last year, in 1999. It wasn't a single event, and it wasn't any one time period. It was scattered strandings all the way from Alaska down to Bajamuch larger numbers than we've previously seen."
At the time, scientists speculated that food shortages in Alaska were to blame for the strandings. Scientists believed the whales simply didn't put on enough weight to see them through their migration south to California and Mexico. In the months since the strandings, federal scientists have taken a closer look, and they now offer another explanation.
DEMASTER: "All the models suggest that when you have 26,000 gray whales, given their life span and survival rate, we anticipate anywhere from 1,000 to 1,200 animals dying each year. A big stranding year of 200 or so is still only part of the total population that dies."
DeMaster says that rather than viewing the strandings as a sign the gray whale population is in trouble, he sees them as proof the population has recovered.
DEMASTER: "As long as the population continues to increase, as it approaches carrying capacity, what you'd expect is that you're going to get a lot of variability in the number of animals that die in a given year. It doesn't mean the population is in trouble. It means that's how it equilibrates. Mortality has to go up to balance reproduction, and that is how the population stabilizes. I think what we're seeing is this new equilibrium process. We're observing that for one of the first times ever for a large marine mammal population that's recovering. Scientifically, it's exciting. From a management perspective it's positive. But the general public has a hard time getting used to the fact that there's more gray whales that are dead on the beach than ever before."
But while the population of gray whales in the eastern North Pacific is healthy and increasing despite the strandings, DeMaster says the gray whale population that migrates along a corridor from Russia to the South China Sea, is on the verge of extinction.
DEMASTER: "The western North Pacific population is doing terribly. It's the population that feeds off Sakhalin Island. We don't know where it breeds. There's probably less than a few hundred animals. We may lose that population in our lifetime. So that one is a disaster."
Oil and other commercial development around Russia's Sakhalin Islands, uncontrolled hunting and interactions with commercial fishermen all are likely to exact a toll on the gray whale and its habitat. DeMaster says biologists have documented just 70 gray whales in the western North Pacific since the mid-1990s. And he doubts that many more exist.
DEMASTER: "Unfortunately they didn't find a Baja to winter in."
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.
For more information about gray whales, visit these web pages:
Gray Whale Status Report (PDF)
Thanks to the following individual for help preparing this script:
Dr. Doug DeMaster, Director
Ph: (206) 526-4045
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 Homepage
The URL for this page is http://seagrant.uaf.edu/news/00ASJ/05.01.00_GrayWhales.html