Villagers in the coastal Sundarbans mangroves of Bangladesh are using spoons, sponges, and shovels to try to mop up a major oil spill in an area that is home to two rare dolphin species, Bengal tigers, and a diverse array of birds and fish.

The spill began Tuesday, when a tanker carrying about 77,000 gallons of fuel oil collided with a cargo ship. By Friday, according to reports, the oil had spread across 50 miles of rivers and canals.

After visiting the spill on Wednesday, Bangladesh forest chief Yunus Ali told The Daily Star, a Dhaka-based news outlet, that he could not spot any fish or dolphins in the area.

“The dolphin sanctuary will probably be the worst hit,” he said. “But we have to carry out an inspection on the extent of the damage. Small birds that feed on insects and fish, too, will be affected.”

With no emergency response services in the area, ship owner Padma Oil Company has begun paying locals for any oil they can collect.

“It has no commercial value as it can’t be used, but we are using the offer to encourage people so that the cleaning-up process speeds up,” a company official told Agency France-Presse.

People are scooping up oil from the water however they can and emptying it into pits and trenches dug on land.

“It’s a catastrophe for the delicate ecology of the Sundarbans,” Amir Hossain, chief forest official of the Sundarbans, told AFP. “The oil spill has already blackened the shoreline, threatening trees, plankton, and vast populations of small fishes and dolphins.”

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“Animals have started to die,” reported The Daily Star. “The water hyacinths on the two rivers have turned black. Some Golpata trees have gone under heavy layers of oil. One local, Abu Jafar, spotted two animals—a monitor lizard and an otter—dead and smeared with oil” along a riverbank. Animals that come to the river to drink will also be harmed, one expert told the Star.

Local forest officials are in dispute with regional officials about using dispersants or other additives to help control the spill, according to reports.

The Sundarbans, a 3,800-square-mile delta of canals and rivers spanning the coastlines of Bangladesh and India, is a UNESCO world heritage site as well as a government-recognized wildlife sanctuary. The area shelters much of the world’s remaining population of endangered Irrawaddy dolphins, as well as Ganges dolphins and Bengal tigers.

The spill could affect wildlife in the area for decades to come. In Alaska, regional herring and killer whale populations have never recovered from the Exxon Valdez oil disaster in Prince William Sound in 1989. Despite cleanup efforts, people are still finding spilled Valdez oil on the region’s beaches, under rocks and between boulders.