The British Antarctic Survey has launched an investigation following a fatal attack on a marine scientist by a leopard seal.

Kirsty Brown, 28, was snorkelling about 25 metres from the shore near Rothera base when she was suddenly dragged under the surface. The shore cover team immediately called in a rescue boat, which reached the scene within 10 minutes, but the station doctor was unable to revive her.

“This is tragic and shocking,” said BAS director Chris Rapley. “My heart goes out to Kirsty’s family and her colleagues at Rothera. Kirsty was a vibrant, dynamic individual, committed to her science and with a promising scientific career ahead of her.”

Spokesperson Linda Capper told New Scientist that BAS safety regulations mean that scientists do not enter the sea if a leopard seal is seen, and leave the water immediately if one arrives. The seals are inquisitive, she says, but in 30 years of diving and snorkelling no BAS personnel has ever been attacked.


Rare attacks

Rare attacks by the large and fierce-looking seals have been reported. In 1985, Scottish explorer Gareth Wood was bitten twice on the leg as a seal tried to drag him off the ice into the water. Wood’s companions beat off the seal by repeatedly kicking it with the spiked crampons on their boots. Ernest Shackleton’s record of his 1914-16 Antarctic expedition also records an attempted attack.

Kirsty Brown was a qualified and experienced diver, says Capper, and all safety procedures had been followed. The BAS enquiry into her death will run in parallel with an official coroner’s enquiry.

Her research was on the catastrophic effect that the grounding of icebergs in shallow waters has upon the marine life living on the seafloor. Up to 99.5 per cent of visible creatures can be wiped out by an iceberg impact, making it the most devastating natural disaster known to strike living communities on Earth. Brown was checking equipment at a study site when she was attacked.

Dinosaur-like

Leopard seals (Hydrurga leptonyx) are large but slender seals, with big heads and jaws that give them a frightening, dinosaur-like appearance. They can be up to 3.4 metres (12 feet) long and weigh over 500 kilograms.

They are clumsy on land, but can swim at speeds up to 40 km/h (25 mph). Their main source of food is krill, but they also frequently eat smaller seals. Penguins and fish are less common prey. They are the only seals to regularly eat other seals and penguins.

As well as underwater attacks, the seals also surge out of the water near the edge of ice shelves and snap at prey. Antarctic expeditioners are warned to keep away from the ice’s edge for this reason. Inflatable boats at the US Antarctic base Palmer were fitted with puncture guards in 1999 after repeated leopard seal attacks.

There are hundreds of thousands of Leopard seals in the Antarctic, although they are solitary animals. Their only natural predators are killer whales.