MANILA - The whale shark, locally known as "butanding," has been listed by an international environmental network as an endangered species.

The International Union for Conservation of Nature (IUCN), in a report released early July, listed whale sharks and winghead sharks as endangered, and Bornean orangutans as critically endangered, a step away from going extinct.

"It is alarming to see such emblematic species slide towards extinction," said Jane Smart, Director of IUCN's Global Species Programme.

"These new IUCN Red List assessments emphasise how urgent it is for the conservation community to act strategically to protect our planet’s incredible diversity of life. The world’s oceans and forests will only continue to provide us with food and other benefits if we preserve their capacity to do so."

IUCN said numbers of the whale shark (Rhincodon typus), the world's largest fish, have decreased to more than half in the last 75 years due to growing human pressures. They also get killed by ship propellers.

Conservation efforts in India, the Philippines and Taiwan have stopped large-scale fishing of whale sharks in these countries. However, they continue to be caught in other areas such as southern China and Oman.

Whale sharks are also often found with tuna, and end up getting caught by fishermen targeting tuna.

"While international Whale Shark trade is regulated through the species' listing on the Convention on International Trade in Endangered Species (CITES), more needs to be done domestically to protect whale sharks at a national level," says Simon Pierce, lead Red List assessor, member of the IUCN Species Survival Commission (SSC) Shark Specialist Group, and co-founder of the Marine Megafauna Foundation.

The IUCN lists animals under categories like Least Concern (LC), Near Threatened (NT), Vulnerable (VU), Endangered (EN) and Critically Endangered (CR).

The Philippines is one of the countries visited by the whale shark. It has boosted tourism in some provinces in the Philippines, including Sorsogon and Cebu, where tourists are given a chance to swim with these gentle giants.