ScienceShot: King Crab Invasion

The king crab Neolithodes yaldwyni is invading. Once confined to the deep ocean surrounding Antarctica, the crustacean has begun to creep up the continental shelf. Using a remotely operated vehicle, scientists have found large numbers of the crabs hundreds of meters higher than previously known, the team reports online this week in the Proceedings of the Royal Society B. As the crabs encroach into new territory, they're wreaking havoc on other sea life, wiping out up to three-quarters of the local species of sea floor dwellers. Because waters in and around the sea floor basin where the crabs were spotted have been warming about 0.01°C per year in recent decades, the basin's crabs—which now number more than 1.5 million—and their progeny are poised to climb even higher in the next 10 to 20 years, the team estimates. If the crabs indeed proliferate and move to shallower waters, their effect on sea floor ecosystems around Antarctica—which have evolved for millions of years without shell-crushing predators such as crabs, sharks, and bony fish—could be devastating.

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