An Economic Analysis for Pond Culture Systems of Nile Tilapia

Abstract

Aquaculture is very promising in Ghana particularly Nile tilapia (Oreochromis niloticus) culture. Little information is known about the cost of Nile tilapia production. The various culture systems in producing Nile tilapia (Oreochromis niloticus) with or without African catfish (Clarias gariepinus) predation in ponds were used in order to obtain the economic viability as well as assist in financial planning for fish farmers in Ghana. Three scenarios were used in this study namely, mixed sex with or without African catfish predation and all male (Hand sexed) were the three Scenarios that were evaluated in this study. An ideal pond size of 600m² was used for all the three systems and three fingerlings per meter squared were used as stocking rate. Complete compound feed was used throughout the production cycle for all the above listed scenarios. A twenty year project plan was made for all the three systems. The production cycle was one year, of which harvesting was to be done. All male tilapia production proved superior to polyculture and mixed sex without predation. It has a Net Present Value (NPV) of US$12,399.49 as polyculture and mixed sex culture without predation has NPV's of US$11,042.41 and US$1,358.13 respectively at the discount rate of 10%. Internal Rate of Return (IRR) for all male tilapia culture was 37%and Benefit Cost Ratio (BCR) of 1.43.34% IRR for polyculture and BCR of 1.44.17% IRR for mixed sex culture without predation with a BCR of 1.06 also at 10% discount rate. Sensitivity analysis is also calculated to know the most sensitive of all the parameters. For this reason, +10% (1.1) is added to all the parameters and -10% (0.9) is also added to the parameters. In all, cost is the most sensitive in all the parameters. Revenue is the least sensitive for mixed sex without predation and all male tilapia production but discount rate is the least sensitive in polyculture. The De Graaf model is used to calculate at a given point in time, the number of fish that will be in the pond. To achieve this, natural mortality and predator mortality is calculated each month in order to know the number of fish that will remain in the pond in every month. Mixed sex without predation has the largest number of fish at harvest time as three fourth of the biomass at harvest was made of recruits. The predator density reduced with time as the African catfish are known to be highly carnivorousand voracious predators.On the other hand, there was a slight increase of the all male tilapia culture due to human error as the male selection was manually done. The study recommends that farmers should practice all male tilapia production as fish gain uniform and big size, it yields high returns and harvesting can be done in a short time. In addition to that, the government together with the Fisheries Ministry should organise more trainings on the manual selection of the male tilapia in order to avoid the few incorporation of females into the supposed all males' tilapia production system resulting in the recruits.