WWW.WAS.ORG • WORLD AQUACULTURE • JUNE 2015 67 growth in outdoor ponds (Rodgers et al. 2006). Stocking density could be contingent on the target size of the nursery product. For example, red claw crayfish sold for the ornamental trade should be stocked at densities that provide the greatest length at harvest because larger crayfish fetch higher prices in this market. Conversely a buyer of juvenile red claw might prefer greater stocking densities in the nursery because it typically holds the promise of lower production costs. Feed conversion ratio should also factor into a nursery manager’s stocking decisions. This study showed greater efficiency of feed use as stocking density decreased. Further research is needed to investigate the economic tradeoffs between different stocking densities as related to the greater feed resource use versus the higher price received for the final product, should nursery stocking densities be kept at a low level. This study is a stepping stone in developing appropriate management strategies for small-scale red claw crayfish hatcheries. Because red claw crayfish aquaculture in the United States is embryonic, farmers should develop their own hatcheries and nurseries to build up local production. The physical size of the final product from a red claw crayfish nursery can be customized by manipulating stocking density, which is a useful tool to address ornamental and food markets for this species. References Barki, A., I. Karplus, R. Manor, S. Parnes, E.D. Aflalo and A. Sagi. 2006. Growth of red claw crayfish (Cherax quadricarinatus) in a three dimentional compartments system. Aquaculture 252:348-355. Masser, M.P. and D.B. Rouse. 1997. Australian red claw crayfish. Southern Regional Aquaculture Center 244. Pinto, G.F. and D.B. Rouse.1996. Growth and survival of the Australian red claw crayfish Cherax quadricarinatus at three densities in earthen ponds. Journal of World Aquaculture Society 27:187-193. Rodgers, L.J., P.I. Saoud and D.B. Rouse. 2006. The effects of monosex culture and stocking density on survival, growth, and yield of red claw crayfish (Cherax quadricarinatus) in earthen ponds. Aquaculture 259:164-168. Rodriguez-Canto, A., J.L. Arredondo-figueroa, J.T. Ponce-Palafox and D.B. Rouse. 2002. Growth characteristics of the Australian red claw crayfish, Cherax quadricarinatus. Journal of Applied Aquaculture 12(3):59-64. Saoud, I.P., J. Ghanawi, K.R. Thompson and K.R. Webster. 2013. A review of the culture and diseases of red claw crayfish Cherax quadricarinatus (Von Martens 1868). Journal of the World Aquaculture Society 44:1-29. Webster, C.D., K.R .Thompson, L.A. Muzinic, D.H. Yancey, S. Dasgupta, Y.L. Xiong, and L. Manomaitis. 2004. A preliminary assessment of growth , survival, yield, and economic return of Australian red claw crayfish Cherax quadricarinatus, stocked at three densities in earthen ponds in a cool, temperate climate. Journal of Applied Aquaculture 15:37-50. TABLE 1. Results from a study to evaluate the effect of stocking density on production parameters of red claw crayfish nursery culture. Density (no./m2) Harvest wt (g) Harvest length (cm) Survival (%) FCR 120 7.2 6.1 69.4 1.54 240 5.4 5.5 68.6 2.15 360 4.0 5.0 64.6 3.16 FIGURE 6. Red claw crayfish were weighed individually at the end of the 60-d study. FIGURE 7. The length from the rostrum to the telson of individual red claw crayfish was measured. This study is a stepping stone in developing appropriate management strategies for small-scale red claw crayfish hatcheries.
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