The objective was to analyze the influence of the Tucuruí dam in the small-scale fishery performance, developed in its downstream. Assuming that the imbalance of the Tocantins river had so intense impact over the life of local human communities, affecting their fishery activity performance, we tried to give an answer to the following question: what is the influence of the Tucuruí dam, Pará state, on the performance of small-scale fishing developed in its downstream? Data used are from primary and secondary sources. We used the model of exploratory factor analysis (EFA), in order to build the performance index of small-scale fishing (IDPA). The results show that 21% of fishermen have low performance and, 79%, mid-performance, a fact that points to the difficult situation faced by fishery workers over time.