Peixe-boi da Amazônia (trichechus inunguis natterer 1883): mortalidade e uso do habitat na reserva de desenvolvimento sustentável Piagaçu-Purus, Amazonas, Brasil.

Abstract

The Amazonian manatee (Trichechus inunguis) is endemic to the Amazon basin and the only exclusively freshwater sirenian. Because is difficult to collect systematic data in the wild, the local knowledge of riverine communities has been the main source of populational and ecological information for this endagered species. In order to support long term conservation strategies for the species, the goal of this study was to assess the current status of the population on T. inunguis mortality in the Piagaçu-Purus Sustainable Development Reserve (PP-SDR), Amazonas state, Brazil. This study was organized in two chapters, with different approaches and methodologies. In the first chapter, the manatee mortality in the last 25 years in PP-SDR was estimated using interviews with 39 informants (manatee hunters or local residents who had contact with the species), and the perceptions of local community members on the conservation of the species in the region were recorded. Relevant information about the minimum number of manatees killed by direct or indirect capture, methods of hunting and its relationship with the flood pulse were provided by respondents. Overall, the results indicate positive changes in the manatee conservation attitude in the region, mainly after creation of the reserve. In the second chapter, the occupancy and probability of detection of Amazonian manatee was investigated in 16 floodplain and aria lakes of the PP-SDR and the effectiveness of two sampling methods for estimating occupation of the species was evaluated. Data collection consisted of visits to 33 sampling points between August and November 2014, which corresponds to the Purus River low water season. Within 265 hours of observation effort, 91 manatee evidences were recorded. As expected, the species was not always detected when present. The combined use of direct and indirect methods to detecting the Amazonian manatee provided more precise occupation estimates. The results show that generated impacts by residents of the studied communities, such as commercial fishing and transit of vessels, are not interfering in manatee occupation because the highest probabilities of occupation of the species were closer to human communities. These findings seek to contribute to future conservation projects and monitoring of the species in the Piagaçu Purus SDR and in the Brazilian Amazon.