Morphological Differentiation of Wild and Hatchery-Bred Clarias gariepinus from Two Different Populations

Worldwide, the consumption of aquatic food has increased tremendously at a rate almost double that of annual world population growth rate, pushing the annual per capita consumption to a very high record in 2019. Clarias gariepinus is a fish species that has gained wide acceptance in regions of the world mostly for aquaculture usage. Generally, in aquaculture, stock identification is paramount to the success of aquaculture activities and fisheries science employs various techniques for stock identification among which conventional techniques (morphometric) still play a significant role. In view of the aforementioned, this study evaluated homogeneity and heterogeneity between wild C. gariepinus from Igun Abandoned Gold Mine Reservoir and hatchery-bred stain from Leventis Foundation Farm from Osun State, Nigeria. Twenty-one morphometric traits examined were subjected to t-test, Principal Component and Cluster analysis using Paleontological Statistical (PAST) software. The t-test results revealed that weight, pelvic fin length, snout length, diameter of eye, anal fin length and dorsal fin length differed significantly (P<0.05) between the two populations while the remaining characters’ differences were not significant. The study further revealed a highest Eigen value of 64.725%, with length of spine as the character most responsible for variation, wild and hatchery-bred populations clustered almost intersected completely (95% ellipse) and Bray-Curtis’s clustering analysis showed similarity of 91%. The result elucidated the extent of homogeneity and heterogeneity based on morphometric analysis, the morphometric differences serve as a guide to selecting stocks for breeding programs which is considered a potential for commercial fish farming, however genetic marker studies (RAPD) can still be used to either complement or confirm the phenotypic diversities between the populations.