[Stingrays in rivers in southeastern Brazil: occurrence localities and impact on the population]

Abstract

Introduction: In this paper, our aim was to describe the process of colonization of the upper Paraná basin, southeastern Brazil, by stingrays, showing the current situation, likely trend and impact caused and discussing some management actions and mitigation measures.

Methods: Interviews were held with riverbank people and health professionals, to gather information on occurrences of stingrays and accidents associated with these animals, along with underwater observations and collection of specimens, between 2004 and 2009 in localities in the States of São Paulo, Paraná and Mato Grosso do Sul, in the southeastern, southern and part of the central-western regions of Brazil.

Results: Three species of stingrays were identified in the study area, thus demonstrating that they were using the paths opened by the Tietê-Paraná Waterway to disperse. Sixteen victims of accidents involving these animals were found, mainly bathers and fishermen. Attention was drawn to the fact that these cases had not been reported, yet they presented high morbidity with notable temporary incapacity for work.

Conclusions: This is the first report on biological invasion involving species of elasmobranchs in the literature and, because stingrays are colonizing densely populated areas and are expanding their range of distribution each year, it can be expected that their negative interactions with humans will intensify, with important changes in the epidemiological profile of accidents due to venomous animals occurring in southeastern Brazil.