MANILA— A conservation group and the Philippine government are offering a reward for information about those responsible for the killing of an 18-foot (5 1/2-meter) whale shark.

The World Wildlife Fund says the whale shark — the world's biggest fish species— was found early this week in a cove south of Manila with its fins sliced off and rope and knife marks on its tail.

The Bureau of Fisheries and WWF on Friday offered a 100,000 peso ($2,170) reward for information leading to the culprits' arrest. Whale sharks are considered protected since 1998 with a maximum penalty of four years in jail for poachers.

Whale sharks have been hunted for decades and 2.2 pounds (a kilogram) of dried fins can fetch up to $800. (AP)