King Crabs Migrating Into Antarctic Waters, Researchers Say

U.S. and Swedish researchers say king crabs are moving south into the warming waters of the Antarctic, a habitat that until recent years had been too cold for them to survive. Using underwater cameras, scientists aboard the Swedish icebreaker Oden have documented large populations of red king crabs over a 30-mile stretch of deep-sea habitat along the western Antarctica Peninsula during the recent Antarctic summer. While those waters had been too cold for the crabs previously, the average ocean temperature has increased about 1 degree Fahrenheit in recent decades, said Sven Thatje, an evolutionary biologist at the University of Southampton in England and chief scientist on the cruise. That slight change has apparently been enough to remove physiological barriers that had kept the crabs out of the region, he told The Washington Post. The migration of crab populations may pose a new threat to other deep-sea species living in the region — including mussels, brittle stars, and sea urchins — that have not developed defenses against the clawed predators. “The Antarctic shelf communities are quite unique,” Thatje said. “This is the result of tens of millions of years of evolution in isolation.”