Crab invasion threatens cancer cure

The king crabs are coming up from deep waters, 1800 to 2700 metres below the surface. Image: Shutterstock.

Thousands of king crabs are converging on Antarctica.

Shell-crushing crabs haven’t been seen in Antarctica for thousands, maybe millions, of years. But now these crustaceans are poised to march up the Antarctic slope and onto the shelf.

Dr James McClintock from the University of Alabama in Birmingham says the vulnerable ecosystem of the shelf surrounding the Antarctic continent could be wiped out. The Antarctic clams, brittle stars and snails have soft shells and have never had to deal with shell-crushing predators.

McClintock stated in the press release that these creatures could be the main prey for these crabs. “You can take an Antarctic clam and crush it with your hands.”

And it’s not just the molluscs that will suffer if the crabs invade the waters around Antarctica. Their loss could jeopardise the discovery of compounds that can fight diseases, such as sea squirts, which produce an agent that fights skin cancer.

But if the crabs eat them, McClintock’s research with that organism will come to an abrupt halt. “I am very concerned that species could disappear, and we could lose a cure to a disease.”

Dr Sven Thatje from the University of Southampton (UK) witnessed the start of the invasion in 2007, when he spotted a lone crab heading up the slope. This discovery led to an expedition to Antarctica earlier this year to search for signs of the invaders.

McClintock said they discovered hundreds and hundreds of king crabs. “(This) could translate into millions across broad expanses of coastal Antarctica. They are adults, males and females. They appear healthy and have all the ingredients needed to produce a healthy population.”

The large numbers of crabs on the slope also suggests that they are increasing at a faster rate than scientists anticipated. McClintock said “Before long, they could be in shallow water and on the shelf.”

Researchers are investigating the cause of the invasion, which they believe may be linked to climate change. “This is just one example of a species expanding its range into a new territory. There will certainly be more as the climate warms up.”

“This is a very visual, visceral way of thinking of an impact of climate change.”

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