Low water levels in the Lower River Murray below Blanchetown, caused by a combination of low Murray inflows associated with the millenium drought from 1995 – 2012 and water abstraction, had degraded vital habitat for small native fishes, including the only known southern Murray-Darling Basin (MDB) habitat of the Southern purple-spotted gudgeon (Mogurnda adspersa) (SPSG). A rescue operation was undertaken in early 2007 as an urgent conservation measure in response to drying wetland habitat. This project sought to secure the population of SPSG by establishing a suitable facility to maintain and spawn rescued fish, and develop support structures and options for species’ recovery, including a greater awareness of the plight of threatened MDB fishes.
The program resulted in a small-scale purpose built fish holding facility which comprised a temperature controlled room containing a 16 broodstock holding aquaria, and six fry rearing aquaria. The production of fry is now achievable within the facility and has been successfully undertaken (and can be undertaken at a larger scale on demand). At the time of completion, a survey was conducted for potential release sites for captive bred fish, but extreme drought conditions meant that suitable release habitats could not be found (they were dry).
Implications for native fish
The current project successfully established a controlled, secure premises for holding and breeding small-bodied conservation-dependant species, and built capacity to ensure a future for the Southern Purple-Spotted Gudgeon population. Long-term success will ultimately be measured by return and re-establishment of wild habitat. A stepping stone approach to establish sustainable populations for use as a stocking source is seen as the best way forward, and the ability to stock larvae has now been developed.
Note: The hatchery has since been de-commissioned.
Drought expert panel report
Hammer, M. 2008. Securing the southern purple-spotted gudgeon in the southern Murray-Darling Basin: establishing captive maintenance. Aquasave Consultants, Aberfoyle Park. 6p.
Lintermans, M. and Cottingham,P. (eds.) Fish out of water-lessons for managing native fish during drought. Final Report of Drought Expert Panel. MDBC Publication No. 29/07, Murray-Darling Basin Commission, Canberra.
Hammer, M., Wedderburn, S. and Van Weenen, J. (2009). Action plan for South Australian freshwater fishes. Native Fish Australia (SA), Adelaide.
Briggs, G. (1998). Murray-Darling Mogurnda adspersa. Fishes of Sahul 12, 543-556.
Brown, C., and Day, R. L. (2002). The future of stock enhancements: lessons for hatchery practice from conservation biology. Fish and Fisheries 3, 79-94.
Faulks, L. K. (2003) The ecology of the southern purple spotted gudgeon. BSc Honours project report thesis, Macquarie University.
Gale, A. (1914). Notes on the breeding habits of the purple-spotted gudgeon, Krefftius adspersus. Australian Zoologist 1, 25-26.
Hammer, M. (2007a). Status report on South Australian threatened freshwater fish populations during 2007 drought conditions. Report to Department for Environment and Heritage, South Australian Government. Aquasave Consultants, Adelaide. p. 20.
Hammer, M. (2007b). Report on urgent conservation measures and monitoring of southern purple-spotted gudgeon on the River Murray, South Australia. Report to the South Australian Murray-Darling Basin Natural Resources Management Board. Aquasave Consultants, Adelaide. p. 15.
Llewellyn, L. (2006). Breeding and development of the endangered Purple-spotted Gudgeon Mogurnda adspersa population from the Murray Darling. Australian Zoologist 33, 480-510.