Protection for a peculiar-looking endangered animal found in the waters of northern Australia could be on the way thanks to a three-year study with scientists and fishers.

Sawfish are a type of modified ray, with a saw-like nose on its head, called a rostrum, and a shark-like body, which can grow up to seven metres long.

The rostrum alone can reach up to three metres.

Marine scientist Vinay Udyawer said the unique body part put the population at risk intentionally and incidentally.

"Sawfish populations have been declining rapidly across their global range," Dr Udyawer said.

"Historically, sawfish were also lucrative for their fins and rostrums, but now this trade in Australia is regulated, and sawfish are not allowed to be kept."

He said sawfish remained targeted as a source of food in Indonesia and Papua New Guinea, but in Australia, most sawfish died after being caught in nets targeting other species.

"Other key processes that also are impacting sawfish populations is the modification of coastal and river systems," he said.

Modification of coastal and river systems includes diverting rivers, building dams, or any modification that changes the natural flow of water.

Sawfish are among the world's most endangered sharks and rays, according to the Queensland state government.

"The green sawfish have reduced drastically since the 1980s, which were once found in New South Wales but have not been reported from there in a long time," he said.

Northern Australia is the "stronghold" for sawfish in the Asia-Pacific region, with four out of five species found there.

Unlikely heroes

Sawfish emerged more than 60 million years ago, according to the Commonwealth Scientific and Industrial Research Organisation (CSIRO).

It's not known how many sawfish remain in the wild, with the species' "elusive nature" and remote habitat causing difficulties for environmentalists.

Dr Udyawer said while fisheries had been blamed as the primary driver of sawfish deaths, scientists needed fishers' help to better understand the species.

"Previous research expeditions have often struggled to catch sawfish or encountered very few," he said.

"These are historically rare animals that are found in remote habitats not frequented by most people.

"Collaborating with local fishers, who operate in areas where these species are found, proves to be a very effective way to study sawfish and their interactions with coastal fisheries."

Scientists began collaborating with fishers in 2021, interviewing 16 working and retired professional fishermen as part of the project.

Their knowledge was used to locate, tag and document sawfish population distribution.

It also increased knowledge about sawfish occurrence, interaction rates and post-release movements.

Charles Darwin University's Natasha Stacey said it was unique to collect and interpret the knowledge of the Northern Territory's professional fishers for a conservation project.

"Fishers are often quite wary of providing any data to researchers or scientists or the government because they're worried about that potentially being used against them," Professor Stacey said.

"It's well recognised professional fishers through their time at sea generate a wealth of knowledge about the environmental conditions they're fishing in."

Parks Australia funded the project, which was supported by the Australian Institute of Maritime Science, Charles Darwin University and the NT Seafood Council.

On boat knowledge

Professional fishers spent several months each year in the waters off Northern Australia.

Peter Manning regularly encounters sawfish as a fisherman in Northern Australia and has helped to untangle and release many sawfish caught in nets over the past 40 years.

"Everything deserves to live; if I'm catching something that's for consumption for food, I've got no problem taking it, but if it's not, I don't like to waste," he said.

Commercial fishing operator Cameron Berryman manages boats across Australia.

He said his NT crew were "pumped" their knowledge was being recognised and used to protect sawfish.

"These guys know where they are — they've got a general idea of their movements — it was great that the scientists came and grabbed the knowledge," Mr Berryman said.

"When you invest in a fishery and you've got a big business you want to look at sustainability and make sure you're doing the best practices and everything you can do.

"We always look at things — without a healthy fishery, we don't have a viable business."

Fishers and scientists will continue to collaborate in the next stages of the project to better understand and protect the threatened species.

Parks Australia's Frances Verrier said this was vital to the project's success.

Watch ABC TV's Landline at 12:30pm on Sunday or on ABC iview.