JOHANNESBURG (AP) — Honking and drumming, hundreds of people have begun protesting in the capital of Mauritius over the government’s handling of an oil spill from a grounded Japanese ship and the alarming discovery of dozens of dead dolphins in recent days.

The protesters on Saturday waved the country’s flag and held up signs with messages such as “You have no shame.”

Thousands of residents were expected to attend the march through Port Louis a month after the ship struck a coral reef offshore and later cracked and spilled around 1,000 tons of fuel oil into fragile marine areas.

The Indian Ocean island nation depends heavily on tourism, and the spill has been a severe blow on top of the effects of the coronavirus pandemic, which has limited international travel.

Authorities on Friday said at least 39 dead dolphins have washed ashore but it’s not yet clear what killed them. Some experts fear the chemicals in the fuel are to blame.

Residents and environmentalists have demanded investigations into why the ship strayed miles off course. Its captain and first officer have been arrested and charged with “endangering safe navigation.”

The ship’s remaining fuel was pumped out before the vessel split in two.