Assessment of Morphological Variation in Wild and Cultured Populations of Tilapia Fish (Oreochromis niloticus)

Reliable estimates of morphometric traits are required for all traits of economic importance to predict response to selection, choose various breeding plans, estimate economic returns and to predict breeding values of stocks for selection. The present study was aimed at assessing the morphometric variation of tilapia fish (Oreochromis niloticus) from different populations. A total of two hundred samples from four populations that cut across two wild [Anantigha river (AN) and Ifiayong river (IF)] and two cultured [Unical fish farm (UN) and Domita fish farm (DM)] were used for the study with fifty samples from each population, respectively. A total of twenty morphormetric traits were measured on each fish. The data were transformed and subjected to multivariate analysis. Results obtained revealed that there were significant differences (P<0.05) in the morphometric traits of the different populations. Body weight was highest in the wild populations (AN =2.32 g; IF = 2.21 g). Correlation analysis revealed high and significant correlation coefficient between the measured traits, where the highest was observed from origin of the dorsal fin to the insertion of the pelvic fin (ODIP) and dorsal origin of the caudal fin to the ventral origin of the caudal fin (DCVC) with correlation coefficient of r= 0.955, P<0.01. Path coefficient analysis revealed that body depth, total length and posterior end of the dorsal fin to origin of the anal fin (PDOA) had the highest direct and positive contributions to the body weight of the fish with path coefficient values of 1.359, 0.943 and 0.673, respectively. Principal component analysis extracted four principal components (PC1 = 65.543%; PC2 = 10.869%; PC3 =7.364% and PC4 =1.327%) contributing to the observed variability among the populations. Hierarchical cluster analysis separated the tilapia fish samples into two major clusters, where fish samples from wild population were group majorly within the same cluster and samples from cultured population also grouped majorly within a common cluster. The findings suggest the strength of morphological traits in distinguishing tilapia populations as well as identifying the morphological traits with high contribution to the weight of tilapia fish which could be targeted for weight improvement.