Estimating Oreochromis nilotica production function for small-scale fish culture in Rwanda

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Nathaniel Hishamunda; Curtis M. Jolly; Carole R. Engle

Type of Document:
Scholarly Article


Aquaculture in the Tropics

Date of Publication:

Place of Publication:
Not Available


Abstract: Consistent low yields are a major problem of many small-scale fish farmers in developing economies. The problem plagues Rwandan fish farmers and is embedded in production factors that act, directly or indirectly, in combination with management practices to influence yields. Little is known, however about the causes and to what extent each factor contributes to the problem. Ordinary least squares (OLS) technique was applied to data collected through a survey of 267 small-scale Rwandan fish farmers, to determine which production and management factors affect yields in Rwanda. Selected variables such as pond ownership, elevation, pond size, stocking density, quantity of compost applied, length of production cycle, ability to pay labour, off-farm income, owner’s age, educational level, and marital status were regressed on Oreochromis nilotica yields. At the 5% level, pond size, stocking density, and length of the production cycle had significant effects on yields. Increased pond sizes and long production cycles impeded fish production in Rwanda. Higher stocking densities resulted in increased fish yields. The model that best describes the O. nilotica production function in Rwanda is linear. Yield-maximizing composting rates are yet to be applied to fish ponds in Rwanda. The study indicates that farmers have gone beyond cost-minimizing pond sizes and production cycles, which are yet to be researched. Under the perfectly competitive fish and input markets and ceteris paribus assumptions, the optimal stocking density was found to be approximately 34,000 fingerlings/ha.

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