Austech Aquaculture

Austech Aquaculture

The Austech Aquaculture project and facility focussed around advancing broodstock, hatchery and nursery technology for redclaw crayfish (Cherax quadricarinatus). This hatchery was designed to be the most productive in the world with several projects undertaken to work toward this goal:

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1. Broodstock systems - Broodstock have traditionally been pond based, however this system raises issues with accurately quantify spawning success, control of genetic lines and potentially costly disease outbreaks. Development of experimental broodstock holding and spawning tanks to facilitate environmental manipulation allowed for greater control over the multiple parameters that influenced survival and spawning success. Early data showed promising results for improved spawning success, volume and financial viability of operating an indoor broodstock holding system.
2. Spawning induction - Spawning of redclaw broodstock occurs naturally during the warmer months of the year, however this is not suitable for commercial production, which requires year-round consistent supply. Environmental manipulation of redclaw broodstock to achieve regular and predictable spawning was achieved, but future trials and development of the associated systems would further improve production yields and efficiency.
3. Redclaw egg incubation intensification - Natural incubation occurs on the underside of the female crayfish, but in a commercial application this can tie-up valuable broodstock and reduce overall production efficiency. Intensifying the incubation stage necessitated the development of a commercial scale redclaw crayfish egg incubation system which could successfully provide for the eggs and craylings once they were removed from the female following spawning. In this system eggs could be incubated in an environment designed to simulate the natural incubation, but manipulated and tailored to improve hatch rates, incubation time and overall success. The systems showed impressive results, not seen in the industry before however, the AquaCon team believe this would be improved with further research and trials.
4. Redclaw juvenile nursery intensification - Following from the intensification of the incubation and broodstock, nursery intensification to handle the increased output was a logical step. By developing intensive nursery systems to produce advanced craylings, the facility could supply craylings at a variety of sizes and ages to pond grow-out facilities. This was advantageous to purchasers who could be supplied with an advanced crayling which was not only more robust but which also reduced the pond space needed for nursery on-farm. Results from these trials and feedback from farms was very promising and warrants further investigation.
5. Environmental enrichment – Key areas in the crayfish development in the hatchery system were identified as lacking in resources that would usually be provided in a wild environment. Enrichment of the animal’s environment through probiotics and beneficial bacteria was determined to be a suitable supplement for the systems and several varieties were trialled. Some confounding variables impacted the outcomes of the trials, but there was some suggestion of improved yields in the treatments, which could be validated through further trials and assessments.