Unidades de conservação e recursos pesqueiros do Baixo Rio Branco, Roraima

Abstract

The creation of protected areas (PA) has been a tool widely used to protect landscapes and organisms of great biological importance throughout the planet, and several studies have demonstrated the influence of these PA not only on the conservation of these environments, but also on the quality of life of the riverside populations, including the Amazon. Studies that assess the importance of PA in the conservation of fish stocks are still incipient, and in Roraima no study in this regard had been carried out. The lower Branco River, the stretch of the state's main river that is below the Bem Querer rapids, maintains the most important fishing community in the region, and most of the federal conservation units established in Roraima, but little is known about the importance of these PA for the maintenance of local fish stocks. As a result, we prepared this study, which aims to determine the effect of PA and environmental conditions on the fish fauna exploited by commercial fisheries in the region and to increase knowledge about their actors. In order to achieve its specific objectives, we chose to structure this work in three main aspects: the first, the elaboration of a history of the fishing activity practiced in the Rio Branco valley, which seeks to understand the context that culminated in the current reality of fishing in the region. The second, a socioeconomic characterization of the fishing actors, which was carried out through the application of questionnaires and identified the low education and qualification of these professionals, the dependence of middlemen in the commercialization of fish and their limitations in the knowledge about the fishing legislation and about the conservation units that occur adjacent to their fishing areas. And the third, a comparative study on the ichthyofauna, sought to infer the effect of these protected areas on fish assemblages that suffer pressure from commercial fishing. For this, nylon gillnets, the main gear used in the region, were used in fisheries inside and outside two federal conservation units (PA), the Viruá National Park and the Niquiá Ecological Station. The collections were carried out in two distinct hydrological periods, low water and high water season, and a total of 1713 fish specimens representing 07 orders, 27 families, 65 genera and 100 species were captured. We compared ecological descriptors such as richness, abundance, biomass and composition of these fish assemblages, but our hypothesis that we would find significant differences was refuted. We did not identify any effect of PA on fish assemblages, but the influence of seasonality and environmental factors such as the distance to Caracaraí, the average depth of the sampled sites, and physical-chemical parameters of the waters such as pH, dissolved oxygen and temperature, but the mere existence of this PA, or its access restrictions, do not affect the fish assemblage. Our results represent a significant advance in the knowledge about the ichthyofauna present in these PA and about the fishing activity practiced in the region, but also demonstrate the need to improve management and management measures in these areas, since many traces of use within the conservation units have been detected. If we really intend to strengthen these PA, conserve fish stocks and, at the same time, preserve the way of life of the traditional populations that use these resources, we need to make a lot of progress, but there is still time.