marine biology

North Pacific’s sea slug invasion linked to mystery ocean blob

Unusually warm waters in the Pacific Ocean are driving dozens of species of nudibranch – a photogenic type of sea slug – northward at a surprising pace.

This could signal the beginning of a major climate shift in the region, says Jeffrey Goddard, a marine biologist at the University of California, Santa Barbara. Read more in New Scientist.

Clawing Their Way to Victory

Research suggests fiddler crabs with regenerated claws have distinct fighting strategies.

Male fiddler crabs have one oversized claw, which they use to both attract females and to fight other males for the best breeding burrows on the beach. These fights can get violent, and crabs will sometimes lose their big fighting claw in the process. Fiddler crabs have the ability to regrow their claw, though the new one will never be as sturdy as the original, says Daisuke Muramatsu, a biologist at Kyoto University in Japan.

Even in their weakened state, the crabs must fight. Yet based on his new research, Muramatsu argues that fiddler crabs are more strategic fighters than we’ve given them credit for: he says they pick battles that account for their handicap, and use a strategy of bluff and counter-bluff to end disputes before they begin. Read more in Hakai.

Repelling a Hunter

Scientists are still not really sure if, or how, magnetic shark repellents work.

Sharks get a bad rap, though sometimes for good reason. At times they can be a nuisance, or even a threat. They eat endangered seals; occasionally take a bite out of unsuspecting swimmers and surfers; and, to their own detriment, get caught in gear intended for other fish. Technology that would allow people to repel hungry sharks might save countless lives—particularly the sharks’. Read more in Hakai.