Variation in the Morphometry Measurements of Two Tilapia Fish Species in Relation to Their Body Weight Obtained from Lower Benue River at Makurdi, Benue State Nigeria

This study examined the morphometry of Tilapia zilli and Oreochromis niloticus from lower River Benue at Makurdi. Seven morphometry measurements (body weight, standard length, total length, dorsal fin length, caudal fin length, head length and body width) of each captured fish. The mean of morphological parameters of Tilapia zilli of body weight, standard length, total length, dorsal fin length, caudal fin length, head length and body width were 12.83 g, 8.00 cm, 9.95 cm, 4.50 cm, 3.19 cm, 2.27 cm and 4.44 cm respectively. Similarly the mean morphometry of Oreochromis niloticus was body weight: 15.51 g, standard length: 9.00 cm, total length: 10.76 cm, dorsal fin length: 5.85 cm, caudal fin length: 3.68 cm, head length: 2.67 cm and body width: 4.41 cm. The correlation analysis between morphometry of Tilapia zilli was significant between head length and total length only. However, correlation analysis between morphometry of Oreochromis niloticus revealed a significant positive correlation between standard length and bodyweight, total length and body weight, standard length and total length, dorsal fin length and body width and head length and dorsal fin length only. There was a strong relationship between log of body weight and standard length using regression analysis with R2 value of 0.8689 in Oreochromis niloticus while a weak relationship was obtained in Tilapia zilli with R2 value of 0.0889 during the study. The study concludes that the two species of the Tilapia are different with different morphological features used in its identification.