ABSTRACT: This study provides foundational information in terms of genetic variation and morphology of O. niloticus in three water bodies in the south-western region of Nigeria. A total of one hundred and nine individual samples of Oreochromis niloticus were obtained from the study locations for morphological studies. The study indicated that there was a high morphological variation in the fish from all locations and that, not all the morphological features of O. niloticus in the study areas contributed significantly to the variations observed. The PCA loadings for the entire region showed that the head height (HH) is the character that contributed most to the variance observed in the study. The scatter diagram, using 95% sensitivity, indicated that fish samples from Awara and Egbe reservoirs have morphometric features that are more related than those from Ogbese River as confirmed by Mann-Whitney U-test. The result from the PCA of meristic characters was different, the measured characters did not vary within the same population except scales count on two samples from Ogbese River. The observed variation in the meristic characters occurred mostly within the entire region. The results from the study indicated that the reservoirs have more diversified O. niloticus.
Keywords: Morphology; Morphometrics; Meristics; Oreochromis niloticus; Nile Tilapia
JoST. 2021. 11(1): 60-70
Accepted for Publication, January 29, 2020
