A whopping 35 freshwater fish are being recommended for national listings as being at risk of extinction after an Australia-wide survey.
One species, the Kangaroo River perch, is also thought to be extinct but quirkily is not eligible for listing without a formal scientific name.
The fish has not been seen in the waterways of Kangaroo Valley in New South Wales for 26 years, although there are still some hopes it is still alive somewhere in the wild.
Study lead author and freshwater fisheries ecologist Mark Lintermans, from University of Canberra, said more people should be aware of the sad story of the perch.
“It’s a salient lesson to know you’ve lost a fish species,” he said.
“What it should do is ring the alarm bells to put more resources in saving the ones we’ve got.”
Raising that alarm is what Dr Lintermans hopes to achieve after working with scientists from government departments, museums and universities to compile the first comprehensive review of the country’s freshwater fish which was published in Biological Conservation.
Eighty-eight out of 241 species assessed, using the International Union for Conservation of Nature red list of threatened species guidelines, were deemed to be threatened with the majority most at risk of extinction less than 15 centimetres in length.
The biggest threats for threatened fish included introduced species like trout, disease, habitat alterations from development and climate change.
The status of some species already on the national register of threatened species, such as the freshwater sawfish (Pristis pristis) were also recommended for elevation to critically endangered status.
The freshwater sawfish has been recommended for an uplisting to critically endangered from vulnerable. (Supplied: Sharks and Rays Australia/Barbara Wueringer)
But the study also suggested the status of some species such as trout cod (Maccullochella macquariensis) should be down-listed from critically endangered to near threatened and for Murray cod (Maccullochella peelii) to no longer be considered under threat.
Dr Lintermans said it was important for species to be delisted when appropriate so funding could go to the right places.
“If you don’t take the ones that no longer need action off the list you have a false set of priorities,” he said.
And those priorities he said should be focused on some of our smallest species.
Murray cod have been recommended for delisting off the threatened species list. (ABC Landline: Sean Murphy)
What’s at risk?
Freshwater species are some of the most susceptible animals in the world to the changing climate, especially smaller species that utilise smaller creeks and waterholes.
About 78 per cent of the 40 species from the fish family Galaxiidae, a group of cool-water species mostly found in upland lakes, rivers and streams, were found to be under threat by the study.
Dr Lintermans said the biggest threat to Galaxiids was introduced species of trout, which eat the smaller fish.
“There is a conflict there with recreational trout fishing and stocking done by a whole lot of state agencies,” he said.
“We just need to be cleverer about that and work with the trout fishing fraternity better.
“We need to set some waters for endangered native fish and some for recreational fishing.”
Mark Lintermans, a freshwater fisheries ecologist at the University of Canberra, has studied native species for more than 40 years. (ABC News: Michael Barnett)
Dr Lintermans said some jurisdictions like Victoria and Tasmania, where trout have become self-sustaining, were starting to address the conflict.
In some instances trout have been removed from waterways for native species.
But the broader issue, Dr Lintermans said, was there was still no national mechanism for managing the impact of invasive fish on freshwater species.
Call to recognise invasive species as threats
Dr Lintermans said invasive fish, including trout, redfin and carp should be recognised by the federal government as a “key threatening process” which would help multi-jurisdictional collaboration.
That could then help funding into measures like captive breeding programs and mapping and identifying invasive-free refuges for priority conservation.
“There isn’t much in the way of climate change planning for fish in Australia at all, so that’s another deficiency we have,” Dr Lintermans added.
“We really need some sort of dedicated funding and research [on invasive species] to improve the tools we have.”
Large dams are also lacking research into how their fragmenting of fish populations could be offset.
Waterfalls provide a natural barrier to trout stopping them from eating smaller native species. (Supplied: Mark Lintermans)
Dr Lintermans said the Department of Climate Change, Energy, the Environment and Water also needed to list the individual species identified by the study.
“The threatened list is a long way behind, it’s in catch-up mode,” he said.
“In 2020 they only had about 40 species of freshwater fish, now they have 63.”
Adding the 35 identified species to the list and removing one, the Murray cod, would take the total of officially threatened fish to 97.
That’s about a third of all freshwater fish with more than 300 species in Australia.
The Biodiversity Council, an independent expert group of Australian universities, wants to see the species identified as threatened added to the national list.
Jess Marsh, a Biodiversity Council councillor and University of Adelaide taxonomist and ecologist, wasn’t involved in the study but said it would help species conservation.
“This [study] is important to assess the impacts of threats and also the effectiveness of conservation actions,” she said.
“Conservation is often heavily skewed towards the cute and the cuddly taxa, with heavy biases against taxa, such as fish, invertebrates and fungi.
“But these taxa are functionally important for biodiversity and so addressing these biases is an important task.”
Bull sharks are already listed globally as vulnerable, but fish scientists want a similar listing in Australia. (iNaturalist: Craig Lewis, Bull shark, CC BY-NC 4.0)
A DCCEEW spokesperson said the government was committed to its target of zero new extinctions.
“The Australian government is supporting landscape-scale conservation efforts as well as species-by-species action,” they said.
“We are investing over $550 million to directly protect threatened species and ecological communities and to tackle invasives.”
But one species is teetering on the precipice of being officially listed as Australia’s first totally extinct freshwater fish.
The search for the Kangaroo River perch
The threshold for declaring an extinct species officially is a high bar.
Exhaustive surveys of a known range are required and enough time past taking into account the lifetime of a species that it would be unlikely to still survive.
The Kangaroo River perch, a genetically distinct species related to Macquarie perch, was regularly caught by anglers up until the 1990s.
No wild records of the species exist after 1998.
Nick Whiterod, a Goyder Institute for Water Research ecologist and study co-author, said he would never say never, but it wasn’t looking likely the species still existed.
“Any species loss is terrible,” he said.
“But what this really highlights is we could be on the edge of a whole range of different species being wiped out and lost.”
The Kangaroo River perch is unique to the Shoalhaven area of New South Wales. (ABC Illawarra: Justin Huntsdale)
The NSW Department of Primary Industries and Regional Development is still looking for the species, however, and has surveyed with electrofishing, fyke netting and collecting environmental DNA.
A department spokesperson said the most recent survey in 2023 from 20 locations had not detected DNA from the species but they weren’t giving up yet.
“Further funding has been secured to continue the ‘search for the perch’ project,” they said.
“With additional sites being targeted for both eDNA and traditional fish survey methods in the coming months.
“Members of the public who think they may have seen the fish or have caught one historically are encouraged to contact DPIRD Fisheries.”
While the search continues for the Kangaroo River perch, states like Victoria have implemented new initiatives to try to stop other species sharing their unknown fate.
The Moroka galaxias is a critically endangered freshwater fish which is part of a breeding program in Victoria. (Supplied: Tarmo Raadik/IUCN Red List)
The state opened a conservation hatchery a few months ago for freshwater species as a collaboration between the Victorian Department of Energy, Environment and Climate Action and the Victorian Fisheries Authority.
Jarod Lyon, a principal research scientist at the hatchery, said there were about 30 species in Victoria that needed to be worked on and the current push was to get down listings for 10 fish, mussel and crayfish species.
“It was off the back of the 2020 fires it started because we had all these endangered species in Gippsland,” he said.
“It became apparent there would be more fires and increasingly we need to be a bit more proactive than reactive.
“One of the first times a fisheries agency has stepped in this direction because historically a lot of stocking was for creating fishery values for people to catch fish.”
The hatchery is starting to make inroads and one of its target species, Moroka galaxias, recently laid a bunch of eggs.
Dr Lintermans hoped more funding would go towards these kinds of breeding programs so the futures of other threatened fish could be secured.
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