The report provides a comparative perspective on the social and economic dimensions that interact with biological variables in the conduct of fish culture in the various locales. The report also summarizes major dimensions of variability in the financial incentives presented to producers across the sites. The objectives of the study are three: first, to profile the farming system, fish production practices, and household circumstances of tilapia farmers in four PD I A CRSP countries; second, to examine the economic incentives and constraints confronting tilapia producers in terms of market signals, input costs, and the relative profitability of various experiment-based tilapia production strategies; and third, to provide an overview of the institutional context of the POI A CRSP in each country's program of tilapia technology development and transfer.