BANGKOK (AP) — A top marine biologist is urging Thailand’s government to speed up conservation plans for the dugong, an endangered sea mammal, after their death toll for the year has already climbed to a record 21.

Thon Thamrongnawasawat said on his Facebook page that the carcass of a dugong was found Tuesday off the southern province of Krabi. The young female apparently drowned after being caught in a fishing net.

Experts believe only 250 dugongs are left in Thai waters.

Thon, who has served on a government environment committee, says a three-year master plan for dugong conservation is awaiting Cabinet approval.

The plan is called the "Marium Project" after the name given a much-loved ailing baby dugong who died two months ago under the care of veterinarians after her rescue.