Anxious residents of Mauritius created makeshift oil spill barriers on Saturday as tonnes of fuel leaking from a grounded ship put many and endangered wildlife in further jeopardy.

The Indian Ocean nation has declared an environmental emergency and France said it was sending help from the nearby island of Reunion.

“When biodiversity is in peril, there is urgency to act,” French President Emmanuel Macron said on Saturday.

The country has appealed to the UN for urgent aid and advice from environmental protection experts.

“We are in a situation of environmental crisis,” said the country’s environment minister, Kavy Ramano.

A police inquiry into possible negligence has been opened, the government said.

A military transport aircraft was carrying pollution control equipment to Mauritius and a navy vessel would set sail for the island nation, France said from Reunion on Saturday.

Residents and environmentalists alike wondered why authorities didn’t act more quickly after the ship ran aground on a reef on July 25.

Mauritius says the ship, the ‘MV Wakashio’, was carrying nearly 4,000 tonnes of fuel.

“That’s the big question,” Jean Hugues Gardenne, of the Mauritian Wildlife Foundation, told The Associated Press. “Why that ship has been sitting for long on that coral reef and nothing being done.”

He said it was the country’s first oil spill and perhaps no one expected the ship to break apart. For days, residents peered out at the precariously tilted boat as a salvage team arrived and began work, but ocean waves kept battering it.

“They just hit and hit and hit,” Mr Gardenne said.

Cracks in the hull were detected a few days ago and the salvage team quickly left the scene. About 400 booms, used to contain oil on the sea’s surface, were sent, but they were not enough.

Mauritian Prime Minister Pravind Jugnauth says the spill “represents a danger” for the country of 1.3 million people, which relies heavily on tourism and has been hit hard by the pandemic.

“Our country doesn’t have the skills and expertise to refloat stranded ships,” he said on Friday. Bad weather had made further action impossible, he said.

“I worry what could happen Sunday when the weather deteriorates.”

Online ship trackers showed the Panama-flagged bulk carrier had been en route from China to Brazil. The ship’s owners are listed as the Japanese companies Okiyo Maritime Corporation and Nagashiki Shipping Co Ltd.

In a statement, Nagashiki Shipping said: “Due to the bad weather and constant pounding over the past few days, the starboard side bunker tank of the vessel has been breached and an amount of fuel oil has escaped into the sea.”

It also said: “Nagashiki Shipping takes its environmental responsibilities extremely seriously and will take every effort with partner agencies and contractors to protect the marine environment and prevent further pollution.”

Heavy wind is expected to push the oil slick farther along the mainland’s shore. A Mauritius Meteorological Services forecast for Sunday advised that seas would be rough, with swells beyond the reefs and ventures in the open seas not advised.

Videos posted online showed oily waters lapping at the mainland, and a man running a stick across the sea’s surface then lifting it, dripping black goo. The Mauritian Wildlife Foundation is working to free trapped seabirds and turtles.

Environmental group Greenpeace Africa issued a warning that tonnes of diesel and oil were leaking into the water. It shared a video showing Mauritius residents shoving the makeshift oil barriers into the sea, to chants of “One, two, three!,” while crowds of children and adults hurried to make more.

“Thousands of species around the pristine lagoons of Blue Bay, Pointe d’Esny and Mahebourg are at risk of drowning in a sea of pollution, with dire consequences for Mauritius’ economy, food security and health,” said Greenpeace’s climate and energy manager, Happy Khambule.