LAUSR

Abstract The capture of ornamental fish is an important economic activity in Brazil. Most (79 %) of the live aquarium fish exported from this country are captured in the Amazon region, in particular in the basins of the Negro, Xingu, and Tapajos rivers. The capture of ornamental fish in the Xingu basin is now under threat from the impacts caused by the construction of the Belo Monte hydroelectric dam, which has resulted in habitat loss and changes in the river’s hydrological cycle. An economic assessment of this fishery is needed to determine the magnitude of the possible impacts for the fishers over the long term. The present study estimated the costs and profitability of the fisheries that target ornamental species prior to the impoundment of the river, based on the records of the catches and economic income of 36 vessels. The results were positive, indicating that this activity was economically viable at that time. The harvesting of ornamental fish requires a mean initial investment of US$ 2,640.14, with a net profitability of 28.63 % for wooden canoes and 18.47 % for aluminum boats, providing the fishers with a net income of US$16.80 per fishing day. However, this income is extremely unstable due to the fluctuations in the capturability of the target species over the course of the year, and unpredictable oscillations in the demand for the most commercially valuable species. The predicted changes in the hydrological systems following the construction of the dam will likely result in a decrease in the economic yield of the fishery. Studies of this type are fundamentally important for the establishment of effective public policies for the fishery sector, and the mediation of socio-environmental impacts in the Amazon region.