Ecologia alimentar da tartaruga-cabeçuda, Caretta caretta (Linnaeus, 1758), por meio da análise de isótopos estáveis de carbono e de nitrogênio, no litoral do Paraná

• Autor(a) principal: Santos, Gleici Natali Montanini dos
• Data de Publicação: 2016
• Tipo de documento: Dissertação
• Idioma: por
• Título da fonte: Biblioteca Digital de Teses e Dissertações da UERJ
• Texto Completo: http://www.bdtd.uerj.br/handle/1/13905
• topic: Stable isotopes; Feeding ecology; Loggerhead sea turtles; Brazil; Isótopos estáveis; Ecologia alimentar; Tartaruga-cabeçuda; CNPQ::CIENCIAS EXATAS E DA TERRA::OCEANOGRAFIA::OCEANOGRAFIA BIOLOGICA

The measurement of stable isotope is a tool that can be used in addition to feeding ecology analyzes, since the isotope composition of a predator is directly related to their prey by a diet incorporated over time. The aim of this study was to analyze the trophic relationship of sea turtle Caretta caretta with preys consumed on the coast of Paraná and observe the differences in feeding of juveniles and adults, by the analysis of carbon and nitrogen stable isotopes. Organisms at the base of the food web (seston) were collected besides, 19 species of prey (n = 94 specimens) which included mollusks, crustaceans and teleost fish, and 20 specimens of C. caretta turtles found stranded dead in the coastal beaches of Paraná (12 juveniles and 8 adults). We have analyzed the isotope ratios of carbon and nitrogen in aliquots of muscle tissue of turtles and its preys. For the carbon isotope ratio, mollusks showed values between -16.9 and -13.7 , the teleost fishes values between -27 and -15 , crustaceans between -18.8 and -15.5 and C. caretta values between -19.5 and -16.0 . As for the nitrogen isotope ratio, mollusks showed values between 10.3 and 13.9 , teleost fishes between 8.9 and 14.8 , crustaceans between 9.5 and 14.3 and turtles between 9.9 and 18.3 . Separating the turtles by maturity class, the juveniles showed mean values of -18.4 and 12.9 and adults of -16.8 and 16.2 for the carbon and nitrogen ratios, respectively. The mollusks species showed carbon stable ratio values higher than turtles, indicating that they could not be a direct prey species, therefore, raised the hypothesis that were predated hermit crabs when they used the empty mollusks shells. The results of carbon and nitrogen isotope ratios indicate the teleost fish as important prey, corroborating with the findings in other studies. With respect to maturity classes, the values for the two isotope ratios tended to increase with increasing the curved carapace length. It found a significant difference in values between juveniles and adults, for both isotope ratios, showing that feed on different prey (Student's t test, p <0.05). Thus, it raised the hypothesis of juveniles are going through a transition phase, when feeding in different environments, or have it fixed in the neritic zone recently. The adults are feeding on prey trophic levels higher than juveniles, so the difference in the isotope ratios. It is therefore concluded that adults and juveniles of C. caretta feed differently on the coast of Paraná and occupy different trophic levels.