The carrier was en route to Brazil from China and held 3,894 tons of low-sulfur fuel oil, 207 tons of diesel and 90 tons of lubricant oil, according to the Environment Ministry.

“Due to bad weather and constant pounding over the past few days, the starboard side bunker tanker has been breached and an amount of fuel oil has escaped into the sea,” said Nagashiki Shipping Co. Ltd, owner and manager of the vessel, in an emailed statement. “In view of poor sea conditions salvage efforts are currently on hold.”

A floating barrier has been deployed around the vessel to contain the oil, the shipping company said. The government on Thursday closed some of the country’s beaches.

“It’s the first time that Mauritius is so badly hit by an oil spill,” Vassen Kauppaymuthoo, an oceanographer, said by phone. “It may have caused irreversible environmental damage to the southeastern coast of Mauritius.”