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Mary River Cod “Geraldine” destined to restock our waterways

Mary River Cod “Geraldine” destined to restock our waterways

A breeding program of the Mary River Cod is restocking populations in the Mary River Catchment with Geraldine its leading lady.

At the recent Noosa Festival of Water, Geraldine, a very calm and relaxed 30 year old was seen rebuilding her strength as she prepares to breed new life this Spring.

Geraldine is one of two breeding pairs currently being looked after in tanks by Steve Poole and team at the Gerry Cook Hatchery on the bank of Lake Macdonald at Cooroy.

The fish have now been relocated to outside ponds at the Hatchery, where in a created habitat with simulated logs for lurking and egg laying, the pairs will work out territories and wait – until the water temperature hits about 20 degrees Celsius when they will commence the spawn.

Eggs are laid and adhere to mesh in the “logs”, where they are germinated and then guarded by the males, keeping out predators and fanning the water to keep it oxygenated. Divers carefully transfer the mesh to smaller tanks inside the Hatchery to be monitored and fed a careful diet of plankton and black worms from about 3 – 4 weeks.

Previous successful spawning from two breeding pairs have resulted in in around 10,000 fingerlings released into waterways in the Mary River Catchment and into specific impoundments in south east Queensland.

The Mary River Cod (Maccullochella mariensis) is one of Australia’s most endangered freshwater fish. Natural populations are limited only to the Mary River system in Queensland’s south east and it is estimated that they are in less than 30 per cent of their former range. There may have been as few as 600 Cod left in 1996 when the last comprehensive survey of the species was undertaken.

Steve Poole says the breeding program is a priority action of the draft Mary River Threatened Aquatic Species Recovery Plan.

“Restocking Mary River Cod into waterways in the Mary River Catchment is identified as a priority action in the draft Plan, along with our breeding program.

“The plan is currently being developed by the MRCCC in collaboration with multiple stakeholders including the Australian Government.”

A five year strategy (2016 – 2021) has been developed to guide the operation of the Gerry Cook Hatchery, which is now operating under the auspices of the Mary River Catchment Coordinating Committee (MRCCC).

A Steering Group comprising representatives of the MRCCC, the Department of Agriculture and Fisheries, SeqWater, Noosa Council and recreational fish stocking groups will guide the management of the breeding program and the implementation of best management practices to ensure the gene pool diversity of any fingerlings produced.

Noosa Biosphere Reserve Foundation Chairman, Campbell Corfe, says the breeding program is exemplary of the Noosa people working to maintain Noosa’s biodiversity.

“The resurgence of the Hatchery is another of those compelling stories which abound within the Noosa Biosphere Reserve where volunteer teams get on with the job of maintaining our biodiversity.”