Freshwater catfish at Tahbilk Lagoon

In short

Tahbilk Lagoon is a key refuge for Freshwater Catfish, one of the few sites in Victoria with a relatively abundant population of this threatened species.
Catfish breeding success depends on stable water levels, as rapid fluctuations from environmental water releases can cause nest abandonment and reduce egg survival.
ARI identified spawning in November–December, with juvenile fish appearing by February, highlighting the need for carefully timed water management to support catfish conservation.

Freshwater catfish - photo by Fern Hames

A refuge for Freshwater Catfish

Tahbilk Lagoon near Nagambie, central Victoria, is well known for its biodiversity values which includes several threatened species and vegetation communities. It is an important refuge for the Freshwater Catfish (Tandanus tandanus), being one of the few locations in Victoria with a relatively abundant population.

Recent research has revealed important information about the movements and habitat needs of this threatened species to inform the development of recovery actions. However, more precise information about the timing of breeding was required to ensure environmental water releases would not have impact spawning success.

Freshwater Catfish are unusual in that they build circular nests in shallow areas, commonly made of stones. Males maintain the nest, fanning away sediment and chasing away predators until the eggs hatch.

Environmental water releases are an important tool to ensure adequate flows throughout waterways. However, rapid fluctuations in water levels can cause catfish to abandon nests, reducing the amount of eggs that get laid, fertilised and protected. Although breeding was known to occur over several months during spring to summer, the exact timing of spawning and hatching had not been identified.

Tahbilk Lagoon, an important site for Freshwater Catfish

Tahbilk Lagoon - photo by Fern Hames

A circular nest of stones constructed by Freshwater Catfish during breeding

Circular catfish nest - photo by Pam Clunie

What we did

ARI investigated the timing of catfish spawning by sampling for larvae and young fish of a few months in age. The presence of larvae (10-15 days old) in late November, and young fish (55-60 mm in length) in mid-February indicates that spawning occurred in November-December.

Although further monitoring is required to better understand the timing of breeding in other years, maintaining stable flows in Tahbilk Lagoon during this period is likely to be important to provide suitable breeding opportunities and increased survival of juveniles.

This information will contribute to Freshwater Catfish conservation by guiding management of environmental water releases by the Goulburn Broken CMA. The Tahbilk Lagoon is a great example of long term, integrated research and management, supported by many organisations and individuals.

For more information contact: wayne.koster@deeca.vic.gov.au

Publications

Bringing Native Fish Back - Freshwater Catfish at Tahbilk Lagoon (PDF, 4.2 MB)
(accessible version (RTF, 23.1 KB))

Koster, W. M., Dawson, D. R., Clunie, P., Hames, F., McKenzie, J., Moloney, P. D. and Crook, D. A. (2015) Movement and habitat use of the freshwater catfish (Tandanus tandanus) in a remnant floodplain wetland. Ecology of Freshwater Fish 24(3):443–455

Acknowledgements

The current research was funded through the Victorian Government's Threatened Species Protection Initiative.

Page last updated: 04/12/25