Drunken crabs threaten to reclaim Antarctic

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We don't usually think of the Antarctic as a valuable ecosystem, but a recent clawed invasion of King crabs may put the region into jeopardy, and researchers are twitchy.

Shell crushing crabs that feed on other invertebrates were indigenous to the Antarctic hundreds of thousands, or possibly even millions of years ago. In their absence, evolution paved the way for a whole host of softer shelled clams, snails and brittle stars that now lack any kind of protection should the crabs return.

And that’s exactly what the King crabs are now doing. Normally, the crabs wouldn’t venture into the icy chill of the shelves around the Antarctic, because they struggle to regulate certain ions in their body, namely magnesium. When they can’t do that properly they end up in a kind of drunken state.

Nobody really knows just how many there are at this stage, or just how much damage they’re doing, but initial surveys have found hundreds of them in transects up the coastal shelves – and when extrapolated, that could suggest thousands or even millions of these boozy crustaceans on the move landwards, where defenceless food sources await in blissful ignorance.

A lot of the concern for the region is very anthropocentric, be that right or wrong. Either way, the region is brimming with animals that are an essential component in research for future medicines, especially those in the field of cancer. Once these animals are gone, it closes off a whole potential route of future treatments.

Concerns started back on 2007 when a biologist spotted a lone King crab sauntering up the slopes. Further investigation was quickly proposed, and the results suggest a wave of crabs arriving from between 6,000 and 9,000 ft beneath the icy waters, where temperatures are less hostile.

If they do decide to invade en-masse then the invertebrates in the region will stand little chance. Antarctic clams have now become so soft that it is simple for a human to crush them between the hands. Against the crushing, hydraulic claws of the King crabs, they may as well be wrapped in paper.

The researchers behind the discovery hope to have their findings published in a major journal in the near future. In the meantime, the Antarctic crab phenomenon could be just another indicator of global changes in the face of altering climates.