Analyses of Productivity of Nile Tilapia (Oreochromis niloticus), Red Tilapia (O. niloticus X O. mossambicus) and Pacific White Shrimp (Litopenaeus vannamei) Polyculture in a Recirculating System

Abstract

Improving the efficiency of production, profitability and nutrient utilization are the most important factors for aquaculture companies. Many research efforts have been focused to develop strategies that improve the productive performance of shrimp farms. One recognized strategy is polyculture, which can considerably improve farm production yields by optimizing use of available resources.Tilapia production in shrimp ponds (with and without shrimp) has increased rapidly in many countries including Thailand, the Philippines, Honduras, Mexico, Peru, and the inland desert of Arizona.A current practice in extensive, semi-intensive and intensive culture systems is the integration of tilapia with shrimp to increase total productivity. I tested this hypothesis in the present trials experimentally by co-cultivating tilapia and Pacific white shrimp in closed recirculating systems. The present series of experiments were carried out over a period of three years between 2007 and 2009. All of these studies were developed and conducted at the facilities of the Environmental Research Lab (ERL) of the University of Arizona in Tucson, AZ.A preliminary study included three treatments in low salinity water (5 ppt). White shrimp post larvae were stocked into cylindrical plastic pools and Red tilapias were stocked into aquaria. Equal numbers of shrimp were placed in all the treatments whereas fish (Red tilapia) density was variable. We found good growth and 100 % survival of shrimp and tilapia.The first experiment included five treatments with four replicates each with saline water of 10 ppt. Shrimp and Nile tilapia were weighed and distributed in 20 fiberglass tanks with capacity of 200 liters. There were evaluated finding statistically significant differences in growth of tilapia (P< 0.05) but no significant difference in growth of shrimp at different fish densities (P> 0.05)The second and third experiments included four treatments with four replicates each using the same shrimp density in each study but different fish density by treatment. Results of one-way analysis of variance (ANOVA) for the second experiment showed a significant effect of the shrimp- tilapia polyculture on the growth of Pacific white shrimp (P< 0.05) but not for tilapia (P> 0.05) compared with monoculture. In the third experiment, there were significant differences in the growth of shrimp (P< 0.05) but not significant differences in the growth of fish (P> 0.05). These experiments were conducted using slightly different culture systems.