ANTANANARIVO (Reuters) - Some 55 dolphins have died, after coming ashore on a beach in the northwest of Madagascar, conservationists said on Monday.

The melon-headed whales, a species of dolphin, were first spotted at sea last month, but then became stranded on a beach last week, Herilala Randriamahazo, from the Wildlife Conservation Society, a non-profit organization, told Reuters.

“We have counted 55 dead dolphins today,” Randriamahazo said by telephone from Antsohihy, the seaside town where the dolphins died. They were buried in a mass grave, he said.

American specialists had arrived on Monday to examine possible reasons for the beaching and to lead some remaining dolphins out to sea, he said.

“This is the first time that Madagascar has seen such sea animals,” he said.

A spokeswoman for the Indian Ocean island’s environment ministry said the dolphins had created a stir. “Lots of people are going to Antsohihy to see these animals for the first time,” she said.

(Writing by Ed Harris)