Income evaluation of small - scale fishers in two brazilian urban reservoirs: Represa Billings (SP) and Lago Paranoá (DF)

摘要

The income of small-scale fisheries of two urban reservoirs in Brazil: Represa Billings (127 km2) located in the metropolitan region of S?o Paulo, the capital city of the state of S?o Paulo and Lago Paranoá (38 km2) located in Brasília (DF), the capital city of Brazil were calculated and compared. Both fisheries are mainly based on the alien Nile tilapia Oreochromis niloticus (more than 80% of the total catch). Although these reservoirs are nearly 900 km apart, their native fish fauna belong to the Upper Paraná Province. The Represa Billings fishers have, on average, a daily profit of R$ 15.8 (U$ 8.4 mostly employing gill nets) and Lago Paranoá fishers R$ 46.6 (U$ 24.9, mostly employing cast nets), which is a statistically significant difference (P < 0.001). The profit of the fisheries is explained by the factor "reservoir" and covariate "days of fishing". Due to the increasing violence in the metropolitan region of S?o Paulo, the Represa Billings fishery is vanishing.