Assessment of stocking size and density in the production of redclaw crayfish, Cherax quadricarinatus (von Martens) (Decapoda: Parastacidae), cultured under earthen pond conditions

Redclaw crayfish, Cherax quadricarinatus (von Martens) (Decapoda: Parastacidae),were cultured for 140 days within 24 net pens in a 0.2-ha earthen pond at densities of 3, 9 and 15 m(-2), with mean stocking sizes of either 4.71 g or 16.89 g. Crayfish were fed a formulated supplemental pellet diet. An economic evaluation accounted for price paid per individual at stocking, value of the individual at harvest, and amount of food fed. There was no significant effect of density or stocking size on survival that ranged from 76.6% to 87.5%. As density increased, significant decreases in mean harvest size and specific growth rate occurred for both stocking sizes. Mean food quotients (FQs), yields, and economic returns significantly increased as stocking size and density increased, with large-stocked animals at 15 m(-2) having the highest FQ, yield and economic return. This experiment shows that when stocking with well-advanced juveniles at densities between 9 and 15 m(-2), yields in excess of 5 t ha are achievable in 140 days of culture. (C) 2000 Elsevier Science B.V. All rights reserved.