Effects of controlled artificial incubation on hatching success, morphometric traits, and early physiological indicators in olive ridley sea turtles (Lepidochelys olivacea) from Banyuwangi coast, Indonesia

Background and Aim: Olive ridley sea turtles, Lepidochelys olivacea, are globally threatened marine reptiles whose reproductive success is strongly influenced by environmental conditions at their nests. Artificial incubation has been increasingly implemented to reduce egg mortality from predation, flooding, and anthropogenic disturbances; however, information on its effects on hatchling morphology and early physiological development remains limited. This study aimed to evaluate the effects of controlled artificial incubation using the Intan Room system on hatching success, hatchling morphometric traits, and early physiological indicators of olive ridley sea turtles originating from different nesting beaches along the Banyuwangi coast, Indonesia. Materials and Methods: Eggs collected from three nesting beaches in Banyuwangi, East Java, Indonesia, were relocated and incubated under controlled conditions using the Intan Room system. Incubation temperature and relative humidity were continuously monitored and maintained at approximately 28.6°C and 80%, respectively. Hatching success and incubation duration were recorded for all clutches. Hatchling morphometric parameters, including head dimensions, carapace measurements, plastron dimensions, and flipper lengths, were measured using digital calipers. Yolk absorption dynamics were assessed at fixed intervals after hatching as an indicator of early physiological development. Data were analyzed using descriptive statistics, one-way analysis of variance, Tukey’s post hoc test, and Pearson correlation analysis. Results: Controlled incubation maintained relatively stable thermal conditions within the optimal embryonic developmental range. The overall mean hatching success reached 83.7%, with beach-specific values ranging from 77.6% to 91.4%. Hatchlings from different nesting origins differed significantly in several morphometric parameters, including carapace length, plastron dimensions, and forelimb length (p < 0.05). Hatchlings originating from Sobo Beach generally demonstrated larger morphometric measurements. Yolk sac diameter progressively decreased during the first 9 h post-hatching, and yolk absorption dynamics showed significant positive correlations with carapace length, carapace width, and foreflipper length (p < 0.01). Conclusion: Controlled artificial incubation using the Intan Room system effectively supported high hatching success under stable thermal conditions. Nevertheless, morphometric and early physiological variation persisted among hatchlings from different nesting origins, indicating that pre-incubation biological factors continue to influence developmental outcomes despite environmental standardization. These findings emphasize the importance of incorporating nest provenance and standardized egg handling protocols into hatchery management programs to improve sea turtle conservation strategies. Keywords: artificial incubation, conservation management, hatchling morphometrics, hatching success, Indonesia, Lepidochelys olivacea, physiological development, yolk absorption.