The Stocky Galaxias (Galaxias tantangara) is a relatively unknown species to many Australians. First described in 2014 by Tarmo Raadik, the species are commonly 65–90 mm and are dark olive-brown on the back and upper sides, becoming lighter brown to cream ventrally. The species can be distinguished from the similar Mountain galaxias by the presence of spotting that extends onto the top of the head, cheeks, and jaws.
Dwelling high up in the mountain country of Kosciuszko National Park, the species are often hard for researchers to find. They are known to live in a tributary of the Upper Murrumbigee River upstream of the Tantangara Dam in NSW. It is found here because of predatory trout who, to date, have not made it above the falls where these little fish live.
During the 2019-2020 Black summer bushfires, the amount of sediment and ash entering the creeks and waterways posed a serious threat to Australia’s small-bodied fish.
Just days after the fires ravished the land around the Upper Murrumbidgee River, 143 Stock galaxias were rescued and taken to Gaden Hatchery. This small group was then secured as an insurance population for the entire species.
You can hear more about the rescue of the Stocky Galaxias from Associate Professor Mark Lintermans in this podcast episode:
Recent updates
Fellow Stocky lover Luke Pearce (NSW DPI Fisheries) presented on the recent developments in their recovery at the Native Fish Forum 2024. He found that despite the devastation of the fires, out of the catastrophe was born an opportunity to increase our knowledge of the species.
The DPI Gaden Hatchery and Charles Sturt Uni (CSU) have been building out the bigger picture of this species and sharing their learnings.
They have been working on refining housing and husbandry techniques as well as the dietary preference of juveniles. So far, they have discovered unexpected aggression in the species! The feisty little fish ended up being housed in individual tanks to stop them from fighting.
The team at CSU are leading the captive breeding program to arm us with the knowledge for future steps.
They are also researching:
- Over wintering
- Hand stripping
- Nutrition
- Egg and larval rearing
SWIMMING STOCKIES!
With no known area to release captive breed fish back into the wild that had suitable habitat and did not contain trout or other galaxiid species, the team got creative and decided they had to build one! The team was able to create a series of linking streams between existing dams with channels for water flow at Eucumbene Borrows – a disused Snowy Hydro quarry site which was converted into a haven for Stockies.
The team also installed:
- Solar-powered pumps
- Instream habitat augmentation – e.g. rocks
- Fencing to control access of people and feral animals
- 10Ha riparian and instream revegetation
- Regular trout surveys and control to maintain the site as predator free
Finally, all their hard work paid off and in April of 2023, more than 120 Stocky Galaxias were released into their new home at Eucumbene Borrows.
So, what’s next?
Luke outlined the next steps for Stockies as:
- A catchment survey to identify wild reintroduction sites
- Ongoing genetic management
- PHD student starting Stocky research in 2024
- Further works to drought proof Eucumbene Borrows
- Ongoing captive breeding at CSU
- Further releases into Eucumbene Borrows
- Potential barrier construction and trout removal
- Investigate potential to reconnect populations
Additionally, Luke highlighted that there is whole galaxy of galaxiids that are out there need attention too! There is potential future research opportunity to apply some of these methods and techniques to the other 13 critically endangered and 5 endangered galaxiids.
There is still much more to know about these little fish and the changing climate presents a large challenge to their long-term survival. However, the people working to save them are collaborating and uniting their ambition to advance our collective knowledge of these mysterious small-bodied fish.
Featured image: Stocky Galaxias
Source: Tarmo Raadik
