The Napoleon wrasse (Cheilinus undulatus) is an ecologically and economically significant reef species native to Indo-Pacific coral reefs region, but it is increasingly threatened by overfishing and habitat degradation. Despite its endangered status under the IUCN and CITES Appendix II, there are limited data available on the growth patterns and physical condition of juvenile C. undulatus, especially in the wild. Thus, this study aimed to assess the length-weight relationship (LWR) and condition factor (K) of wild-caught juvenile C. undulatus. A total of 150 juvenile C. undulatus were bought from fishermen in Tandubas, Tawi-Tawi, Philippines. Samples were analyzed for its total length and weight using standard biometric methods. The LWR analysis of wild C. undulatus revealed a positive allometric growth pattern (b = 3.09), indicating that the fish grew more in weight than length, a typical trend in juvenile fishes. A coefficient of determination (R²) of 0.92) demonstrated a fitness of the data on the positive linear equations. It suggest the positive correlation of weight and total length in juvenile C. undulatus. Furthermore, the average K of 1.543 indicated that the juvenile C. undulatus were in good physical condition, suggesting favorable environmental conditions in their natural habitat. Overall, the study implicates the coral-reef conditions of Tandubas, Tawi-Tawi where C. undulatus thrive.
