Numbers of endangered sawfish in one of their most globally important strongholds are dropping, with conservationists calling for a rules that will cut the numbers of animals being caught in commercial fishing nets in north Queensland.
In September, a two-week private expedition to monitor and tag sawfish in the Norman River, Queensland, returned without finding a single sawfish.
Sawfish are known for their distinct protruding toothed saw – or rostrum – that can detect electrical signals and movement from nearby prey before swiping at it. Some sawfish can grow to seven metres in length, with the saw accounting for about one-quarter its length.
The largetooth and green sawfish are internationally listed as critically endangered, and the dwarf and narrow sawfish are listed as endangered. All four exist in coastal habitats in the Gulf of Carpentaria, considered to be a global stronghold for sawfish.
Guardian Australia can reveal three conservation groups have written to the Department of Environment asking for a suite of rules and restrictions to be imposed on the Queensland-managed Gulf of Carpentaria Inshore Fin Fish Fishery.
A national recovery plan for three of the sawfish species, published in 2015, states the main threats include commercial, recreational and unregulated fishing, Indigenous fishing and habitat changes. The sawfish rostrum easily tangles around ropes and fishing nets.
Aquarist Nicole Weller, of the Sea Life Sydney aquarium, returned from a 14-day sawfish monitoring trip in the Gulf of Carpentaria in September without finding a single sawfish.
Weller said they searched across three different sites along the Norman River but poor weather and murky water made the task harder.
She said: “We were looking to find them, measure them and tag them. We were hopeful that we would have found at least one, so to not get any was disappointing.”
Dr Barbara Wueringer, founder and principal scientist at Sharks and Rays Australia, a conservation group that organised the trip, said they had been visiting river systems over the past five years to gather data on sawfish.
She said: “We do know the numbers have declined. Northern Australia is the last global stronghold for four of the five species of sawfish. It is critical on a global scale what happens up there.”
She said her organisation was working with commercial and recreational fishers in the area and believed most people shared concern for the welfare of the animals.
“Because they have this saw, people like to take a trophy and that’s something that we want to stop. Nobody should remove the saw,” she said. “They need to release the animals with minimal damage and as quickly as possible. Most fishers have good methods and know how to handle them, but because there’s no training provided they sometimes come up with bad methods.”
Prof Colin Simpfendorfer, of James Cook University, says a lack of data makes it hard to be sure of exact numbers of sawfish, but added: “I would be confident to say they’re at levels lower than they have been historically.
“We know that fishing continues to interact with sawfish, particularly the gillnet fisheries in Queensland and the Northern Territory. They’re not targeted by fishing, but they are being caught. We have to deal with this bycatch issue so that animals can be released safely.”
He said pressures on sawfish were less in western areas of the gulf in the Northern Territory where there was little fishing activity.
The Queensland Department of Fisheries has applied to the federal government for a renewal of the Wildlife Trade Operation for its Gulf of Carpentaria fishery. According to its application, some 395 “sawfish and rays” were caught as bycatch in the fishery between 2003 and 2017.
Conservation groups WWF, the Australian Marine Conservation Society (AMCS) and Humane Society International, have written to the federal environment department to ask for a range of restrictions to be placed on the fishery to stop sawfish being caught.
In a submission seen by Guardian Australia, the groups say a lack of rules in the fishery would “likely to lead to the extirpation of sawfish” and the rare “speartooth” river shark.
Dr Leonardo Guida, a campaigner at AMCS, said “to help the survival of the species” the “most tangible and effective” step would be to remove gillnets from critical habitats.
He said a lack of independent observers on boats in the region meant that reported bycatch numbers were likely an underestimate, adding: “We can’t be sure how many sawfish have been caught, or what species, and we don’t know the fate of them.”
Dr Richard Pillans, a CSIRO research scientist, said it was “irrefutable” that the numbers of sawfish left were much lower than they were “100 years ago”.
He said the level of reporting of sawfish as bycatch was “generally acknowledged to be an underestimate”.
The environment minister, Sussan Ley, said that due to concern for the conservation status of the narrow sawfish, on 29 September she had prioritised the species for a threatened species assessment under the EPBC Act.
She said: “The department is currently assessing the new application from Fin Fish Fishery’s against the EPBC Act and a fundamental part of that assessment will be to ensure that all reasonable steps are taken to minimise the impacts of fishing on all bycatch species, including protected species.”
She added the government had invested more than $850,000 over the past four years on the national recovery plan for sawfish and river sharks.
A spokesperson for the minister added she was “cognisant of the concerns raised by conservation groups and the public regarding bycatch of sawfish and speartooth shark in the Gulf of Carpentaria Inshore Fin Fish Fishery.”
A Queensland Department of Fisheries spokesperson said under its Sustainable Fisheries Strategy, “the Queensland Government has committed to undertaking ecological risk assessments for priority fisheries.”
An assessment of Gulf of Carpentaria fisheries was currently underway, the spokesperson said.
The department said while a “number of sawfish are caught in nets” many were “successfully released alive.”
Publicly available data from fishing logbooks show only 46 sawfish had died from capture between 2006 and 2018, but this data covers all of Queensland.
Fisheries Queensland was also looking at “additional education” to help fishers with techniques to release sawfish.
The spokesperson added: “It is illegal to be in possession of any part of any no-take species, which sawfish are under fisheries legislation in Queensland. This means that it is illegal to be in possession of a sawfish rostrum.”
