Comparative Analysis of Length-Weight Relationships and Condition Factors of Pond-Grown Nile Tilapia (Oreochromis niloticus L.) Across Sexes and Life Stages During the Wet Season in Lubao, Pampanga, Philippines

Assessing biometric parameters such as length-weight relationship (LWR) and condition factor (K) is vital in aquaculture for evaluating fish growth performance, health, and adaptability under specific culture conditions. This study investigated the influence of sex and life stage on the LWR and K of the Nile tilapia (Oreochromis niloticus L.) cultured in ponds during the wet season in Lubao, Pampanga, Philippines. A total of 400 specimens were collected from 20 earthen pond farms, comprising 267 males and 133 females with 142 juveniles and 258 adults. Total length (TL) and weight (W) were recorded, and LWR and K were determined. Statistical analysis revealed no significant difference in LWR slopes between sexes (P= 0.878; r²= 0.90 for both), indicating uniform growth patterns under consistent feeding and environmental conditions. In contrast, juveniles and adults differed significantly in LWR slopes (P< 0.001), with adults exhibiting higher mean TL (17.29 ± 2.60cm) and W (119.10 ± 49.16g) than juveniles (11.68 ± 1.10cm; 31.39 ± 10.19g). K values ranged from 1.76 to 2.06, within the optimal range for healthy tilapia, with adults showing slightly higher values than juveniles. Both sexes displayed positive allometric growth, while life stages showed negative allometry, reflecting ontogenetic shifts in mass allocation. These findings emphasize that while sex may not significantly affect LWR under well-managed conditions, life stage strongly influences biometric patterns, underscoring the importance of stage-specific management in wet-season tilapia culture.