Thousands of endangered penguins have been coated with oil after a cargo ship ran aground and broke up on a remote British South Atlantic territory, officials and conservationists said Tuesday.

The shipwreck also threatens the lobster fishery that provides a livelihood to one of the world's most isolated communities.

The Malta-registered MS Olivia was grounded on Nightingale Island in the Tristan da Cunha chain last week. The ship had been traveling from Brazil to Singapore and contained 1,500 metric tons (1,650 tons) of crude oil and a cargo of 60,000 metric tons (66,000 tons) of soya beans.

The ship's 22 crew members were rescued before it broke in two.

Tristan da Cunha's conservation officer, Trevor Glass, said oil was encircling Nightingale Island and called the situation "a disaster."

The territory's British administrator, Sean Burns, said more than half of about 500 birds gathered by rescue workers had been coated in oil. An environmentalist at the scene estimated that 20,000 penguins might be affected.

Tristan da Cunha is home to some 200,000 penguins, including almost half the world's total of northern rockhopper penguins. The bird is classed as endangered by the International Union for Conservation of Nature and Natural Resources.

Located midway between Africa and South America _ more than 2,800 kilometers (1,700 miles) from the nearest land _ Tristan da Cunha is home to about 275 people who rely on rock lobster fishing for their livelihood.

Burns said he had temporarily closed the area around Nightingale and nearby Inaccessible Island to fishing.

"We are concerned about the potential impact (the spill) may have on the spawning grounds," Burns said. "The lobster fishery is what Tristan depends on. The revenue keeps this island afloat."

Richard Cuthbert, a research biologist with Britain's Royal Society for the Protection of Birds, said the wreck was "potentially disastrous for wildlife and the fishery-based economy of these remote islands."

He said that alongside the threat to penguins and sea life, there was a risk rats from the ship could come ashore and eat the chicks and eggs of native seabirds.

"Nightingale is one of two large islands in the Tristan da Cunha group that are rodent-free," Cuthbert said. "If rats gain a foothold, their impact would be devastating.

The islands' remoteness was complicating clean-up efforts. Tristan da Cunha is usually accessible only by boats that sail nine times a year from Cape Town. Nightingale Island has no fresh water, so the penguins will have to be transported to the main island for cleaning.

A salvage tug from South Africa carrying a seabird specialist arrived in Tristan da Cunha on Monday and was assessing the environmental damage.

Officials said they hoped to bring another vessel carrying a penguin-cleaning team from Cape Town to the islands.

The British government said it was very concerned about the situation, but said it was too early to know what the economic and environmental damage to the islands would be.

(This version CORRECTS Adds details, photos. Corrects 'tonne' to 'metric ton.')