Investigating the effectiveness of a well‐managed hatchery as a tool for hawksbill sea turtle (Eretmochelys imbricata) conservation

Abstract

The critically endangered hawksbill sea turtle (Eretmochelys imbricata) is of conservation concern worldwide. Conservation actions which act to reduce high levels of embryonic mortality aid to boost hatchling production. At Cousine Island, Seychelles, a mixed management method has been adopted to maximize the number of hatchlings entering the ocean. We examined the effectiveness of a hatchery at increasing hatching and emergence success from four seasons of data (2017–2021). Hatchery nests had significantly higher hatching and emergence success across all years relative to nests left in situ (i.e., natural), with inter‐annual variation observed. A greater percentage of in situ clutches was found to be influenced by both crab activity and predation as compared to relocated clutches. Overall, the mixed management approach increased hatching success (mean = 75.1%) relative to the various nest management techniques previously used (2004/2005–2016/2017; mean = 63.5%). By mitigating external influences such as tidal flooding, beach erosion, and crab activity/predation, this study provides evidence for the success of a hatchery in directly increasing hatchling recruitment. Strict and careful hatchery management as well as timely and efficient relocation procedures are needed to minimize potential negative effects of nest relocation.