The giant crab invasion of Antarctica has begunS

In 2008, a team of researchers predicted that warming waters in the Southern Ocean would lead to the arrival of king crabs in Antarctic waters within 100 years. Now, just three years later, evidence suggests that the king crab invasion is already well underway.

Videos shot from remotely operated submersibles (featured below) have revealed that staggering numbers of Neolithodes yaldwyni — giant, red crabs that measure more than a meter across — have begun colonizing and reproducing in Palmer Deep, a basin just over 100 km onto the Antarctic shelf.

But just how many crabs could we really be talking about? The researchers who caught the crabs on film explain in their paper, published in the latest issue of Proceedings of the Royal Society B, the extent of the crab population:

We estimate a N. yaldwyni population density of [10,600/sq km] and a population size of [over 1.5 million crabs] in Palmer Deep, a density similar to lithodid populations of commercial interest around Alaska and South Georgia.

Videos like this one show how the sheer size of the N. yaldwyni, combined with their tendency to tromp recklessly around the seafloor, could have an enormous impact on the region's delicate sediment.

"This is likely to alter sediment processes, such as the rate at which organic matter is buried, which will affect the diversity of animal communities living in the sediments," said University of Hawaii's Craig Smith, who led the research team.

And videos like this one, which show the crabs feeding, have the research team worried for Echinoderms — animals like sea urchins and starfish that Smith says constitute a significant portion of the seafloor life on the Antarctic shelf — which have disappeared from regions inhabited by the crabs, and will likely continue to be wiped out if the crabs continue to colonize new areas of the shelf.

For now, extensive searches of nearby, colder waters have turned up no evidence of N. yaldwyni. These findings, however, suggest not only that the warming of Antarctic waters is what has allowed the crabs to invade, but that if waters continue to warm, the massive N. yaldwni will just continue to spread.

Proceedings of the Royal Society B via New Scientist
Top image by Owen Anderson via