RESUMO
Strategies to improve the hatch success and survival of critically endangered hawksbill turtles (Eretmochelys imbricata) require knowledge of threats to them including pathological conditions. The objective of this study was to describe the mortality and pathology of embryos and dead-in-nest hatchlings on St. Kitts and Nevis. Over the 2019/20 and 2020/21 nesting seasons, the combined mean (SD) hatch success for the two islands was 81.9% (13.2%) and deceased individuals within excavated nests were early-stage embryos (70.7%), late-stage embryos (17.7%), pipped-hatchlings (8.2%) or dead-in-nest hatchlings (3.4%). From 2017 to 2021, a post-mortem examination was performed on 183 turtles, including histology for 116. Anatomical malformations affected 77 (42.1%) examined turtles and included abnormal scute shape or number (22.4%), dysmelia (8.7%), schistosomus reflexus (7.7%) and compressed carapace (7.7%). Microscopic lesions were found in 49.1% of turtles and included tissue mineralization (26.7%, including renal, fetal membrane, liver, heart or muscle), chorioallantoitis (16.2%) and skeletal muscle degeneration and necrosis (10%). Inflammatory lesions associated with fungal or bacterial infections were in the skin (n = 3), chorioallantois (n = 4), lung (n = 3) or yolk sac (n = 1). These lesions may reflect non-specific terminal conditions but their presence in-nest helps explain some of the mortality and pathology documented in hatchlings that die during rehabilitative care. All of the gonads adequately represented for histological determination of sex were female (n = 62), supporting concern for feminization of Caribbean hawksbill turtle nests. The study identifies lesions that could affect hatch and emergence success. The high frequency of skeletal malformations indicates the need for investigations addressing regional impact and pathogenesis, especially genetic and environmental aetiologies including nest temperature. Immediate examination of live hatchlings on nest emergence is warranted to better determine the prevalence of non-fatal malformations that could impact fitness and population genetics.
Assuntos
Tartarugas , Humanos , Animais , Feminino , Masculino , São Cristóvão e Névis , Autopsia/veterinária , Coração , RimRESUMO
Increasing hatchling survival is an important element of conservation of the critically endangered hawksbill sea turtle (Eretmochelys imbricata). Yet, there is little information regarding mortality-associated pathological states of hawksbill hatchlings. The aim of this study was to describe lesions affecting hawksbill hatchlings that died while under rehabilitative care. Forty-four turtles representing the nesting sites of two islands and a 7-yr study period were subjected to comprehensive postmortem examination. The most common lesions included dermatitis (34%), skeletal malformations (23%), and pneumonia (23%). Dermatitis and pneumonia were caused by a variety of presumptively opportunistic bacterial and fungal infections. Fungal infections affected 23% of study turtles, also causing rhinitis and esophagitis. Around half of the cases of dermatitis presented with history of skin lesions, and all those involving periocular areas had clinical history of eye lesions. Pneumonia was not predicted by clinical signs or time in rehabilitation. Malformations included carapace compressions, supra- or subnumerary scutes, and dysmelias with many of those affected having concurrent pathology involving other organs. Other lesions included bacterial yolk sacculitis (15%), skeletal muscle degeneration and necrosis (13%), and acute renal tubular necrosis (13%). The study population was female biased (93%), raising concern for skewed hatchling sex ratios and high incubation temperatures in the eastern Caribbean. The pathology described by this study improves our understanding of threats to hawksbill hatchlings and may be taken into consideration by clinicians when implementing strategies for rehabilitative care.
