Histopathological findings in stranded Caretta caretta (Linnaeus, 1758) on the Paraná coast, Southern Brazil

Abstract

Caretta caretta, one of the five sea turtle species in Brazil, is currently listed as globally endangered. While health assessments are crucial for monitoring population status, they are infrequent and lack systematic implementation. Evaluating the health condition of sea turtles can occur through examinations of both live and deceased animals. Carcasses play a pivotal role in identifying diseases and potential threats impacting the species. Therefore, this study presents the histopathological findings from 20 dead stranded C. caretta along the Paraná coast between 2015 and 2021. All individuals underwent measurements, and necropsies were conducted. The mean curved carapace length (cm) was 67.3 ± 6.9 (49.4 – 81.5). Body condition was classified as good in 13 animals, fair in four, poor in two, and undetermined in one. Fourteen females, four males, and two undetermined sexes were registered, with a mean age of 15.8 ± 3,89 (ranging from 9 – 24) years. Evidence of anthropogenic interaction (10 bycatch interactions, 6 marine debris, 2 oil interactions combined with marine debris) was noted in 80.0% of the animals. Histological changes primarily affected the liver, lungs, spleen, and kidneys, with prominent alterations such as inflammatory infiltrate (interstitial pneumonia, heterophilic splenitis, nephritis, endocarditis), congestion, and hepatic and renal hydropic degeneration. This study significantly contributes to our understanding of pathological findings in stranded wild C. caretta on the Paraná coast, offering valuable insights into the health of these animals and aiding in the conservation efforts to protect their populations.