Length-weight relationship, condition factor dynamics, and feeding preference of Clarias batrachus (Linnaeus, 1758) from the rivers of Bataan, Luzon Island, Philippines

There is a paucity of information on Philippine catfish (Clarias batrachus) thriving in fishery areas in Bataan, Luzon Island, and the Philippines. The study examined the length-weight relationship (W = aLb), condition factor, and stomach content of C. batrachus collected from two major river systems in Bataan (Orani and Bagac Rivers), Philippines. A total of 60 fish specimens (12.4–25.5 cm) were collected using a 12-v electrofishing gear and fishing net. Although the specimens from Orani were significantly larger than those from Bagac, the latter exhibited an isometric growth rate (b = 3). Orani population displayed a negative allometric growth (b < 3). Female and male samples, regardless of site variability, showed a statistically isometric growth rate (b = 3). The condition factor of C. batrachus was K = 1.0, irrespective of site and sex variation, signifying that the populations are in good condition. Five food items were detected in Bagac, with the Gobiidae family emerging as the predominant prey items based on number (48.89%), frequency of occurrence (100%), and weight (72.83 %). Orani recorded three food items, primarily macroinvertebrates (Chironomidae), accounting for 75 %N, 86.67 %O, and a frequency of 91.19%. The Index of Preponderance and Index of Relative Importance recognized Gobiidae and Chironomidae as the two most important food items in Bagac and Orani, respectively. The baseline dataset generated from this study is hoped to provide insights into the current population status of this important fishery resource for improved riverine conservation management.