Characterization of the feeding behavior of the green turtle (Chelonia mydas) in the Juréia-Itatins Mosaic's Conservation Units, South Coast of the São Paulo state

Abstract

The Chelonia mydas occurs most frequently in the Cananeia-Iguape-Peruibe Environmental Protection Area and Conservation Units Jureia-Itatins, using coastal regions of the continent and islands of the region as a feeding area. It presents a habitat change during its ontogenetic development. The individuals migrate from the pelagic environment, in this stage they had an omnivorous diet, when they change this feeding area, to the neritic environment, they can have predominantly herbivorous´ diet. However, recent studies have suggested that both habitats change and, consequently, the diet changes may be optional. The objective of this study was to characterize the feeding behavior of green turtles in the municipality of Peruibe, south coast of Sao Paulo. The data were collected from October/2018 to October/2019, with the monitoring of the beaches and the study of the specimens found. This study was approved by the Ethics Committee on The Use of Animals (CEUA/IBIMM) n°. 008/18 and by the Biodiversity Authorization and Information System (SISBIO/ICMBio/MMA) n°. 50132. In the period, 7 individuals were collected who were submitted to biometrics, necropsy and food content collection to verify their composition. Organic and inorganic constituents were separated and the macroalgae found in the esophagus and stomach samples were submitted to a second screening, using morphology and staining as criteria. The mass frequency of each phylum of macroalgae was calculated. The results showed that the individuals were juveniles with CCL 36.33 cm and presented predominantly herbivore feeding behavior, because there was no food from animal origin, consisting only of shell fragments of molluscs and exoskeletons of crustaceans, whose intake may have been accidental. The total survey of macroalgae present in the esophagus and stomach were Chlorophyta (42.76%), Rhodophyta (33.19%) and Heterokontophyta (24.05%), the presence of diatoms was observed complementing the diet of the animals. In addition, it was found that all had anthropogenic residues in their gastrointestinal tracts, and 73.33% of total constituents found are associated with plastic and plastic bags from fishing activities. It was concluded that the Region of Peruibe is an important feeding and development habitat for the species. A problem related to solid waste pollution was observed which consequently shows the need to develop environmental education work with fishers, population and tourists oriented to recycling and the reduction of anthropogenic actions on site.