A commercial fisher in Queensland has been caught selling bills of sawfish, which experts say are the world’s most endangered marine fish.

In photographs obtained by Guardian Australia, a fisherman can be seen selling the rostrums (their long, saw-like bills) at a market in Mackay in June. There were eight on display, and appeared to be on offer for between $10 and $15.

There are five species of sawfish, and all of them are listed as endangered or critically endangered by the International Union for the Conservation of Nature. All are also listed as “no take” in Queensland, and so catching and selling them is illegal.

Narrowtooth sawfish (Anoxypristis cuspidata) rostra for sale in a market in Mackay in north Queensland, Australia, in June 2016. Photograph: Supplied

Once common in many parts of the world, northern Australia is thought to be one of the last strongholds for the fish, said Colin Simpfendorfer, a leading expert on sawfish from James Cook University.

“This region represents one of the last areas globally that you can still find reasonable numbers, while still lower than historic,” he said.

Simpfendorfer says the fish are so rare they would not be directly targeted by fishers, but they are regularly caught by accident because their rostrums easily get caught in nets.

He said their fins are highly prized for Asian shark fin soup, with a set selling for as much as several thousand dollars. Their rostrums are also sold as decorations, and their teeth are sometimes used by cockfighters as spurs. “So when they’re accidentally caught they’re retained,” Simpfendorfer said.

The Queensland department of fisheries said they have received the photographs and are investigating the matter, but could not comment further.

Under the Queensland Fisheries Act 1994, a person cannot possess or sell any species of sawfish or any part of a sawfish in the state, a spokeswoman for the department said.

“If a fisher takes a sawfish accidentally, the sawfish must be returned to the water immediately unharmed. In addition, a commercial fisher is required to report the interaction,” she said.

The maximum penalty for taking, possessing or selling one of these fish is $121,900.

Simpfendorfer said the rostrums in the photographs were from the species called “narrow sawfish”. He said that species was more commonly seen in Queensland than the others. “We’ve basically seen sawfish disappear from most of their historic range along the east coast, with the exception of narrow sawfish.”



Group of people inspecting a large sawfish caught at the mouth of the Mulgrave river, 1938. Photograph: John Oxley Library, State Library of Queensland

The species can grow to a length of more than 4.5m, although they are rarely seen at that length any more.

Simpfendorfer said the largest species of sawfish – green sawfish – can grow to as big as seven metres and used to be found along the east coast of Australia, even as far south as Sydney. But now they are rarely seen on the east coast at all.

Simpfendorfer said the animals were better protected in Australia than in a lot of regions, but that the country “should do better”.

He said interactions with fisheries are poorly documented, and that a fisheries observer program was needed to properly document how often they are being caught. “We don’t know what level of interaction there is.”

Jim Higgs, Great Barrier Reef fisheries technical adviser at WWF, said the survival of sawfish in Northern Australia was a major global issue.

“All sawfish are no-take species in Queensland and no one should seek to profit if they catch one of these threatened species. Electronic tracking and observers will help stamp out the illegal trade in sawfish fins and bills,” he said.

WWF recently bought and retired two large fishing net licenses in Queensland. “That will provide greater protection for the remaining sawfish populations in Queensland by preventing them being killed as bycatch,” Higgs said.

Fishing was not the only pressure on sawfish, Higgs said. They require access to river systems to complete their lifecycle. “This access can be interrupted by stream dams or reduced water quality from poor land management practices,” he said.