Whale sharks and winghead sharks have moved one step closer to extinction, after the International Union for the Conservation of Nature (IUCN) redefined them both as endangered species on the group’s “red list”.

The two predatory species have fallen foul of increased pressure from human activity, especially the fishing industry, with populations of whale sharks – the world’s largest living fish – halving in the last 75 years.

Jane Smart, the director of the IUCN’s Global Species programme said: “It is alarming to see such emblematic species slide towards extinction. 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.”

Whale sharks continue to be killed by ship propellers and fishing fleets, particularly in China and Oman. Whale sharks are often present in tuna shoals, and are frequently landed by fishermen as incidental catch.

“While international whale shark trade is regulated through the species’ listing on the Convention on the International Trade in Endangered Species (Cites), more needs to be done domestically to protect whale sharks at a national level,” said Simon Pierce, the IUCN’s lead red list assessor.

The fast-declining winghead shark – a species of hammerhead – has also proved vulnerable to unregulated fishing, due to its distinctive shape which lends itself to entanglement in fishing nets.

Recent surveys of Indonesian fish markets found only one winghead shark among roughly 20,000 shark species.

The IUCN is expected to publish a full update of its red list of threatened species at its annual world conservation congress in September.