Jungle perch once occurred widely in coastal Queensland rivers, from Cape York to Northern NSW. Central and southern populations have declined or become locally extinct due to dams and weirs blocking migration pathways between saltwater (where they spawn) and freshwater habitats (where they reside as juveniles and adults). Unlike barramundi, mullet and bass; jungle perch cannot persist long-term in saltwater habitats. Barriers lead to rapid local extinction. Construction of fishways on barriers in the past 10 years has created suitable conditions for the reintroduction of jungle perch. There are limited opportunities for natural recolonisation, and remnant adult populations of local strains are too few for translocation to be a practical solution. Restocking from captive bred individuals is the only option to bring back jungle perch fisheries.
Restoring wild jungle perch fisheries is a high priority for recreational fishers in Queensland. Reintroduction of self sustaining populations in rivers in south-eastern Queensland and the Mackay-Whitsunday Region will provide angling opportunities to large populations of anglers. Development of jungle perch fingerling production will also create future opportunities to further enhance Queensland's stocked impoundments and make jungle perch accessible to even more anglers.
Recent research by DEEDI has solved much of the reproductive biology of jungle perch, which can now be spawned regularly in captivity. Jungle perch larvae are much smaller (2.3 mm) than bass and barramundi larvae and establishment of first feeding has been problematic. Strategies to promote larval feeding need to be developed. The transition from larvae to fingerlings is critical for future development of jungle perch fisheries.
This project has for the first time demonstrated the feasibility of hatchery production of jungle perch fingerlings. The research on jungle perch production has enabled a hatchery production manual with accompanying videos to be produced. This has given private commercial hatcheries the information needed to produce jungle perch fingerlings. Several hatcheries have already indicated an interest in producing jungle perch and will be assisted to do so in 2016. Currently jungle perch are not a permitted stocking species, so cannot be sold to fish stocking groups. However, hatcheries will be able to sell fingerlings to the aquarium trade or supply grow out facilities that could produce jungle perch for human consumption. Should jungle perch become a permitted species for stocking, this will provide hatcheries with a major new product option to sell to fish stocking groups. It would also benefit anglers by providing another iconic species for impoundment stocking programs. This could have flow-on benefits to regional economies through angler tourism.
Should the pilot reintroductions of jungle perch into streams result in self-sustaining jungle perch populations, then there will be three restored jungle perch populations close to major population centres. This will create a new opportunity for anglers not normally able to target jungle perch. Since the majority of anglers who target jungle perch are catch and release fishers, angling is expected to have minimal impact on recovery of the populations.
This project led to the development of a hatchery manual for jungle perch production and to a summary brochure. In late 2014 and in 2015 researchers were able to make the first ever releases of jungle perch fingerlings back into rivers and streams within their historical range.
Keywords: Jungle perch, Kuhlia rupestris, hatchery production, restoration, fish stocking, captive breeding, larval culture, recreational fishing.
