'Hoff' yeti crab hitched on ocean super-highway

A hairy crab named after David Hasselhoff hitched a ride on an ocean "super-highway" to cross from the Pacific to the Atlantic millions of years ago, BBC News reported.


The crabs reproduce by releasing many larvae into the water so that a handful reach other vents and colonise them.
But it is thought that they survive for only a short time in open waters; so a strong west-to-east current around Antarctica may have aided their spread.


The animal was discovered in 2011.


The "Hoff" is a type of yeti crab, which is recognised for its hairs, or setae, along its claws and limbs. It lives in one of the most extreme environments on the planet; more than 2,000m under the sea where volcanic vents superheat the water to 380C and there is no light and very little oxygen.


The crab feeds by "farming" bacteria on its hairy chest, then using special comb-like mouthparts to strain off the microbes so that it can eat them.


The crustacean's humorous nickname honors the hairy-chested US actor and singer David Hasselhoff.


In a study published in the journal Proceedings of the Royal Society B, Dr Christopher Roterman and colleagues propose that the "Hoff crab" probably originated around the vents that populate mid-ocean ridges in the eastern Pacific Ocean.


It then expanded into the Atlantic through the Drake Passage that separates South America and Antarctica, spreading along volcanic
vent regions that are now extinct.


The crab appears to have exploited the ocean current known as the Antarctic Circumpolar Current (ACC), which flows in a clockwise direction, west to east around Antarctica, through Drake Passage.


The crabs can occur at astonishing densities around vents in the southern part of their range. But at the volcanic vents of the south-west Indian ridge, for example, the crabs only occur at low densities and are swamped by other vent animals.


Dr Roterman, a zoologist at the University of Oxford, said the exact reasons for this were unclear, but it could have something to do with the crab's reproductive strategy.


"We suspect their [larvae] dispersal capability may be limited," he told BBC News.


"The fact they have spread so quickly in the Southern Ocean is because the ACC provides a high-speed highway for their larvae.


"But when they head further north, we think they may have a disadvantage against other hydrothermal vent animals."