More than 1,000 tons of oil have leaked from a cargo ship and into the shallow, reef-fringed coastal waters of Mauritius, officials said Sunday, imperiling protected habitats and the economy of the Indian Ocean island nation, which relies on fishing and tourism.

Aerial images and drone footage showed miles of shoreline covered with thick, black sludge.

Conservationists in the country say a slow response and rough seas have turned what could have been a minor accident into an ecological and economic disaster.

The MV Wakashio, a bulk-carrying ship that had no cargo, ran into a reef off the southeastern tip of the main island two weeks ago. Battering waves cracked its hull open; it began leaking its engine fuel on Thursday. About 2,500 tons of fuel remained in the ship.

On Friday, Mauritius Prime Minister Pravind Jugnauth declared a state of emergency and appealed for help. By Sunday, France, which held the island as a colony until handing it over to the British in 1810, and which retains possession of nearby islands, pledged military aircraft to help extract fuel from the ship. Japan, where the ship’s owner is based, also promised help.

In a news conference Sunday in Tokyo, Akihiko Ono, executive vice president of Mitsui O.S.K. Lines apologized for the spill and “the great trouble we have caused.” Japan’s Foreign Ministry said it will dispatch a six-person emergency response team at the request of the Mauritian government.

In the meantime, Mauritian environmentalists and coastal residents have worked together to deploy homemade floating devices in the hope of preventing the oil from spreading farther.

Sunil Dowarkasing, a former government minister, called the effort valiant, but said oil had spread as far up the island’s eastern coast as Ile aux Cerfs, a popular resort island. He shared pictures he had taken of oil-covered mangrove swamps along the coast that are renowned as a habitat for plants, insects and birds endemic to Mauritius.

Rough seas have impeded the Mauritian government’s attempts at stabilizing the ship. Five hundred tons of fuel have been lifted by helicopter out of the ship’s hull.

Mauritius is the only African country to report no active coronavirus cases. It shut its borders in March and saw less than a dozen deaths. Locals have been calling for reopening given the economy’s heavy reliance on foreign tourists.