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.

Purple spotted gudgeon. Photo credit: Nick Whiterod

Findings:

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).

Key messages:

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.

Full report: Hammer, M. 2008. Securing the southern purple-spotted gudgeon in the southern Murray-Darling Basin: establishing captive maintenance. Aquasave Consultants, Aberfoyle Park. 6p.

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