Seventeen dead dolphins washed up on the shore of Mauritius, one month after an oil spill from a Japanese ship that ran aground caused a major ecological disaster in the area.
Environmental campaigners say the deaths were either caused by the oil spill from a Japanese-owned ship or by authorities sinking part of the vessel.
But the fisheries minister said "at first glance" the deaths appeared to be unconnected to the spill.
He said at least two of the dolphins had shark bites.
The carcasses are currently undergoing a post-mortem.
"The dead dolphins had several wounds and blood around their jaws, no trace of oil however," Jasvin Sok Appadu from the fisheries ministry said.
A dolphin washed up in Grand Sable, Mauritius. Source: Greenpeace Africa via AAP
"The ones that survived, around 10, seemed very fatigued and could barely swim."
The spill came from the Japanese-owned MV Wakashio, which ran aground on 25 July and began to spill oil about a week later. The ship was scuttled on 24 August.
The full impact of the spill is still unfolding, scientists say, and the damage could impact Mauritius and its tourism-dependent economy for decades.
The sight of the dolphins caused anger among residents.
The MV Wakashio, a Japanese owned Panama-flagged bulk carrier after it ran aground off the southeast coast of Mauritius (AAP) Source: EPA
"Waking up this morning to witness so many dead dolphins on our seashore is worse than a nightmare," resident Nitin Jeeha told the BBC.
"I have seen around eight to 10 dead dolphins. Are there more in the lagoon?"
Although many of the dolphins were found dead, some were discovered weak or dying on the shore.
