Anthropic pressure and causes of death of stranded Chelonia mydas along the northern coast of Bahia - Brazil

Abstract

This study describes the causes of mortality and the primary pathological findings in 61 sea turtles of the species Chelonia mydas that were stranded on the northern coast of Bahia, Brazil. Macroscopic and microscopic lesions were compiled to describe the pathological findings in turtles that were found dead on the beach or that died during treatment at the rehabilitation center of the Fundação Projeto Tamar. Among the 61 turtles evaluated, the cause of death was determined in 96.7% (59/61) of cases. These turtles were affected by natural threats (of infectious, neoplastic, and metabolic origin) and anthropogenic interactions, the latter represented by fishing and/or the presence of anthropogenic waste. 3.3% (2/61) of the cases were classified as inconclusive as to the cause of death, as they were euthanized. Acute respiratory failure was the main cause of death, affecting 45.8% (27/59) of the animals, followed by sepsis in 28.8% (17/59), cachexia/malnutrition in 16.9% (10/59), circulatory collapse due to thromboembolism in 6.9% (4/59), and one animal (1.6%, n = 59) had death associated with gastric impaction. Lesions were most frequently identified in the digestive (58/61), integumentary, visual, musculoskeletal, cardiovascular, urinary, hematopoietic systems, and less frequently in the nervous and endocrine systems. Cachexia, presented based on the observation of muscle atrophy, enophthalmos and plastron concavity, was observed in 49.2% of the turtles (30/61). The results of this study provide information on pathological conditions that may be of clinical relevance for the rehabilitation of animals and their reintroduction to their natural habitat, reducing the impacts of these factors on the conservation of these species and the health of the marine ecosystem.