A new study has found nine different native species of freshwater fish in eastern Victoria face a high risk of extinction in the next 20 years.
The Threatened Species Recovery Hub conducted the research project as part of the Australian Government's National Environment Science Program.
It found the most imperilled fish species in Australia to be the Shaw galaxias — a tiny fish with tiger stripes now only found in one waterway in South Gippsland.
According to the study, the Shaw galaxias has an 80 per cent chance of becoming extinct within the next two decades if no conservation measures are put into place.
University of Canberra freshwater scientist Professor Mark Lintermans said the little fish's biggest threat was introduced predatory fish.
"Like many other smaller native fish species in southern Australia, the Shaw galaxias has been pushed to the brink by trout, predatory species which were introduced to Australia for recreational fishing," he said.
"The Shaw galaxias was once more widespread, but there are now only around 80 remaining — found in a single small population above a waterfall which protected them from trout."
Professor Lintermans said the significant decrease in small freshwater fish populations was also partly due to bushfires.
"These species were already imperilled before the 2019-20 fires, and many are now in even more dire straits," he said.
"They now only inhabit one small area, so a single catastrophic event like a large bushfire could potentially wipe out the species in one hit."
Other threatened galaxias species in the region include the West Gippsland, East Gippsland, Morwell, Dargo and Yalmy galaxias — all of which have a 50 per cent or higher chance of being eradicated in 20 years time.
"Before the Black Summer fires we believed there were up to 2,500 Yalmy galaxias, a species only found in the Snowy River National Park which was badly impacted in the fires," Professor Lintermans said.
"Fire surveys have so far found only two individuals, one male and one female, in separate areas. While there are plans to reunite them as soon as possible, the species is now extremely close to extinction."
Calls for early prevention to save galaxias
With 35 years of experience in eco-management, Professor Lintermans said a collective effort by several authorities was needed to save the precious galaxias species in waterways throughout Gippsland.
"Listing species under legislation may seem like a small step on the road to recovery, but can be key to protecting the last remaining survivors and areas of critical habitat, and can prompt other recovery actions," he said.
"The fate of these species will depend upon individual targeted action, investment, and collaboration among government and non-government organisations to mitigate threats and support recovery."
The Australian freshwater fish at greatest risk of extinction within 20 years:
| Species | Region | Likelihood of extinction within 20 years |
| Shaw galaxias | Vic | >70 per cent |
| West Gippsland galaxias | Vic | >70pc |
| Tapered galaxias | Vic | >70pc |
| Dargo galaxias | Vic | >70pc |
| Morwell galaxias | Vic | >70pc |
| Mcdowall's galaxias | Vic | 50-70pc |
| Malanda rainbowfish | Qld | 50-70pc |
| Stocky galaxias | NSW | 50-70pc |
| Red-finned blue-eye | Qld | 50-70pc |
| Kosciuszko galaxias | NSW | 50-70pc |
| Yalmy galaxias | Vic | 50-70pc |
| East Gippsland galaxias | Vic | 50-70pc |
| Hunter galaxias | NSW | 50-70pc |
| Moroka galaxias | Vic | 50-70pc |
| Barrow cave gudgeon | WA | 50-70pc |
| Swan galaxias | Tas | 50-70pc |
| Short-tail galaxias | NSW | 50-70pc |
| Running River rainbowfish | Qld | 50-70pc |
| SW Victoria river blackfish | Vic | 50-70pc |
| Daintree rainbowfish | Qld | 50-70pc |
| Little pygmy perch | WA | 40-50pc |
| Bloomfield River cod | Qld | 40-50pc |
Source: Threatened Species Recovery Hub
Professor Lintermans said the fish played a vital role in keeping native ecosystem's ticking and he hoped his research would raise awareness about their value.
"Everyone knows about what's happening with Murray cod or barramundi, but there's little fish underwater, out of sight, generally out of mind, and I think it's important for people to know that there's a lot of fish diversity out there and that they're under threat," he said.
"They play an important role in cycling nutrients, in controlling invertebrate populations, they're part of the native ecosystem.
"You lose one brick from a wall it probably doesn't matter. You lose a whole lot of bricks it all falls down. So that's why it's important to protect them."
