Mysterious whale die-off is largest on record

By Jeremy Hsu, LiveScience Contributor
posted: 29 March 2010 08:27 am ET Mass death among baby right whales has experts scrambling to figure out the puzzle behind the largest great whale die-off on record. Observers have found 308 dead whales in the waters around Peninsula Valdes along Argentina’s Patagonian Coast since 2005. Almost 90 percent of those deaths represent whale calves less than 3 months old, and the calf deaths make up almost a third of all right whale calf sightings in the last five years. “This is the single largest die-off event in terms of numbers and in relation to population size and geographic range,” said Marcela Uhart, a medical veterinarian with the Wildlife Conservation Society (WCS). She represents an associate director in Latin America for the WCS Global Health Program. To get to the bottom of the baby-whale mystery, the scientific committee of the International Whaling Commission (IWC) convened an urgent meeting at a workshop in Puerto Madryn, Argentina, this month. Only a few clues have emerged so far regarding the cause of death, such as unusually thin layers of blubber on some dead calves. Whale calves typically have lower chances of survival during their first year of life, but the high rate of death at Peninsula Valdes is unique. Southern right whales are baleen whales that filter their tiny prey from the water with their comb-like mouths. They once represented an ideal target for whalers and nearly went extinct, but began to rebound after a whaling ban started during the 1930s. Still, the whales remain listed as endangered and have yet to recover anywhere close to their historic population levels of 60,000 or more. …

Mysterious Whale Die-Off Is Largest on Record via Sea Shepherd Conservation Society