RESUMEN
When necessary, sea turtles are held captive for veterinarian care and research purposes. Protocols and basic guidelines have been described for husbandry of sea turtles with veterinarian needs but not considering physiological indicators of animal welfare. Because all sea turtle are imperiled species, monitoring their welfare is important. The aim of this study was to standardize husbandry protocols for loggerhead (Caretta caretta) juveniles held under seminatural conditions, based on circulating concentration of plasma corticosterone (Cort) and behavior. Two experiments were performed to analyze physiological and behavioral responses of the animals facing changes in stocking density and different dry-docking times. Cort analyses suggested that the number of animals per tank can be modified occasionally, without affecting their health and welfare. However, dry-docking time should be < 30 min, as indicated by the significant elevation of circulating Cort at ≥ 30 min, rising from 1.51- ng/ml to 5.28-ng/ml. Protocols tested did not affect behavioral responses, except for the breaths per move, which increased while Cort increased, despite differences exhibited by experimental animals in behavioral responses according to daily times (morning vs afternoon) and the sex of the animals.
RESUMEN
Frequently, stranded sea turtles require rehabilitation under controlled conditions. Currently, few publications have described the conditions under which rehabilitation is to take place, particularly with respect to the hatchling life stage. To address this paucity of data, we conducted some experiments to assist rehabilitating facilities assess their handling of hatchlings. While in captivity, hatchlings are routinely handled, for example, for data collection and cleaning. Standardization of handling and housing protocols is necessary to define the most adequate rearing conditions to maintain hatchling welfare. Accordingly, the aim of this study was to assess plasma circulating corticosterone (Cort) concentration and growth, as a biomarker for the stress of hatchling loggerhead sea turtles (Caretta caretta) under controlled conditions. We performed two experiments to analyze handling frequency and stocking density. In both, Cort was measured and correlated with variations in animal weight and length. In handling experiments, Cort exhibited no significant increase when hatchlings were handled once a week, whereas Cort was significantly elevated when hatchlings were handled once every 2 weeks, suggesting that hatchlings have the ability to acclimate to frequent handling. However, hatchlings exhibited similar growth and mortality, regardless of handling regime. In stocking density experiments, hatchling isolation induced a significant elevation of Cort, in comparison with hatchlings placed with conspecifics at increasing densities. Growth increased in singly housed hatchlings, while mortality increased in tanks with three or more hatchlings. The results obtained suggest that Cort, growth, and mortality should be measured to assess hatchling welfare when kept under controlled conditions.
