Estudo da interação organismo-ambiente-sociedade: uma perspectiva ecológica sobre as arraias de água doce (família Potamotrygonidae)

Abstract

The present study aimed to describe the aspects of the distribution, biology and physiology of potamotrigonids from the upper and middle Tocantins River from the point of view of organism-environment interaction and to evaluate the attitudes of internet users on social media about stingrays. The sampling of stingrays was carried out in the upper and middle Tocantins River at various points in the basin. Waiting nets, trawls, longlines, pindás and nasa were used for the capture. During the collections, pH concentrations, dissolved oxygen, conductivity, transparency and water temperature were sampled. The captured rays had their gender and sex identified, biometric data were obtained and subsequently the rays were euthanized and dissected for analysis of their gonads. For Potamotrygon rex ray blood samples were also collected to check the physiological indicators (hematocrit, hemoglobin and plasma glucose). To check the attitudes of Internet users, posts were posted on social media and comments from the publications. The content analysis of the comments posted in the selected media was supported by the IRAMUTEC tool, for the construction of the Descending Hierarchical Classification (CHD) and the similarity tree. The results showed that the physical-chemical characteristics of the water, where the rays live, showed differences, however these variables were not limiting for their distribution along the basin; sexual dimorphism occurs with females being larger than males; stingray species reproduced throughout the year, with the genera regulating the reproductive period from the regional hydrological cycle; it was found that seasonal environmental changes, specifically drought, influence physiology, resulting in an increase in hematocrit, hemoglobin and plasma glucose. It is concluded, therefore, that the potamotrigonids of the upper and middle Tocantins River are well adapted in this environment, presenting physiological mechanisms adjusted to the environmental variations of the water and to the hydrological cycles. Regarding the behavior of Brazilian Internet users, the most frequent were negative, moralistic and ecological. This fish has its blackish image in the social media, where intolerance and the negative discussion about stingrays is most often dissimilar.