Avaliação da população de Botos-do-Araguaia (cetacea: iniidae: inia araguaiaensis hrbek et al., 2014) no Baixo Rio Tocantins, Amazônia oriental

Abstract

The aims of this study were to estimate the abundance and home range size of Araguaian river dolphin’s (Inia araguaiaensis), to characterize their habitat, and to describe their habitat use in lower Tocantins River, Eastern Amazonia. Data were collected in November 2015 and March 2016. When encountered, the dolphins were counted and photographed, their location was recorded and environmental parameters (depth and turbidity) and landscape parameters (distance from sightings to the Cametá market) were measured. Abundance was estimated by marking and recapture method allied to photo identification, and home range was measured by minimum convex polygon method and by Kernel density estimator. Generalized Linear Models were used to evaluate dolphins’ habitat use patterns. Solitary animals and assemblies of up to eight individuals were observed (X ̅ = 6,43 ± 1,13 individuals). Thirteen individuals were identified and a total of 18 dolphins were estimated in the area. Estimated home range and core area were up to 14.55 km² and 5.25 km², respectively. A high frequency of records occurred in front of Cametá market. The distance from sightings to this market was the only metric with a significant effect on habitat use (GLM, z = 2.79, p <0.01). This high frequency is associated with food provision to dolphins in the market.