Production of juvenile redclaw crayfish, Cherax quadricarinatus (von Martens) (Decapoda, Parastacidae) .3. Managed pond production trials

Commercial-scale production of juvenile redclaw crayfish was conducted in earthen ponds. Based upon the results of previous experimental studies in tanks and aquaria, earthen ponds (1300 and 2600 m(2)) were furnished with juvenile crayfish shelters, and were prepared and managed to maximise availability of zooplankton. Juvenile redclaw were introduced by stocking ponds with egg-bearing females. Stocking density, as expressed by number of fertile eggs introduced, ranged from 74 to 326/m(2). Ponds were harvested after culture periods ranging from 45 to 62 days. Juvenile number at harvest ranged from around 6000 to over 36,000, representing a mean of 63.2 juveniles per maternal survivor. Mean size at harvest ranged from 0.31 to 1.00 g, representing growth of 9.7 to 36.9 mg/day. Results suggest that managed pond production of juvenile redclaw is commercially viable at the production rates achieved, and that a considerable increase in productivity is possible with increased availability of shelter and improved zooplankton management techniques.