Denpasar - Two beached bottle-nosed dolphins have been found dead near Serangan Beach in Denpasar, Bali.

The pair, a male and a female, were discovered by officials from the Bali Natural Resources Conservation Agency (BKSDA) during a routine patrol of the Suwung mangrove forest next to the beach, just a few meters from the waterline.

Head of the BKSDA Soemarsono said the officials rushed to carry the dolphins back down to the water but found them unresponsive and stiff.

He said the conservation officials, with help from local fishermen and residents, then brought the bodies back to the BKSDA office for burial.

"We suspect the two dolphins got separated from a larger pod that was migrating through the waters south of Bali," Soemarsono said.

"They probably washed up in the mangrove forest during high tide on Tuesday night. Then when the tide went out, they were left stranded."

He added initial observations showed several lacerations on the dolphins' bodies, which he said were likely inflicted during their attempts to get back into the water.

"We're now running lab tests on skin samples from the animals to determine the exact cause of death," Soemarsono said.

Pariama Hutasoit, an activist with the Beached Mammals Rescue Network (JPMT), said beached dolphins and whales were found on Bali's southern coast all year round.

"In 2010, more than 100 of these mammals were beached on Bali shores," he said.

"It's a trend that increases every year."

He said the last reported case was of an unidentified type of whale, measuring 10 meters long, found beached at Gilimanuk Bay in November. In August, a killer whale washed up on Kuta Beach and was safely returned to the water by locals and tourists.

Pariama said he believed the beached dolphins found on Wednesday had come south from Lovina Beach in Buleleng.

He said the route south past Serangan was their traditional migration route, but they had probably been steered off course by the unseasonably heavy seas battering the island.

Pariama added the JPMT was also running a program to educate fishing communities, maritime patrols and BKSDA officials on standard procedures for dealing with beached dolphins and whales.

"As for those animals found already dead, we want to encourage officials to take tissue samples from the bodies to ascertain the cause of death," he said.