Effect of Rearing Systems (Mono- and Poly-Culture) on the Performance of Freshwater Prawn (M. rosenbergii) Juveniles

摘要

This study was carried out to investigate the effect of mono and polyculture of freshwater prawn with Nile tilapia fry on growth performance and survival rate. Freshwater prawn-juveniles, (M. rosenbergii) averaging (0.30 plus or minus 0.02 g) in weight [Trial 1 (monoculture)] were cultured for 90 days, with different stocking densities (50, 100, 150 and 200 prawn m super(-2)) using 12 circular fiberglass tanks (0.36 m super(2) and 0.6 m in water depth). Prawns were fed manufactured diet contained 35% protein. Water exchange occurred daily with 20% of water size. Growth measurements of prawn were recorded at 15 days intervals. The results showed that growth performance was significantly (p less than or equal to 0.05) decreased with increasing the stocking density. Survival rate was inversely related to stocking density, since there were significant differences among the four densities, while the difference between stocking density of 50 and 100 prawn m super(-2) was not significant. The food conversion ratio FCR increased with increasing the stocking densities, since the fourth density (200 prawn m super(-2)) was significantly higher than that achieved in the first one (50 prawn m super(-2)). Prawn juveniles, of average weight 0.30 plus or minus 0.02 g [Trial 2 (Poly culture)]were stocked (as declared in Trial 1) in poly culture with Nile tilapia fry (average weight 0.3 plus or minus 0.03 g) at stocking density 12 fish per m super(2) for each treatment, for 90 days. Growth measurements of prawns and fish were recorded at 15 days intervals. Results showed that growth performance for fish and prawn were significantly (p less than or equal to 0.05) decreased with increasing of the stocking density of prawn. Survival rate was inversely related to stocking densities, since, there were significant differences among the four treatments. Also, the food conversion ratio FCR for fish and prawn increased with increasing stocking density, since, the differences were significant among the four stocking densities. Therefore, polyculture system is more suitable at stocking density of 100% prawn m super(-2) for optimum growth and survival rate than of monoculture.