Morphometric and Meristic Variation of African Snakehead Fish Parachanna obscura, Günther, 1861 from Nigeria’s Freshwater Environment

Abstract

To attain food security in Africa, the expansion of aquaculture through domestication of endemic species like Parachanna obscura is essential. Optimizing these resources requires a definition of the status of the natural populations that will supply broodstocks and seeds. Morphological variation based on 22 morphological and seven meristic features was investigated. The 12 river basins in Nigeria were purposively selected while one river in each of the basins was randomly chosen for P. obscura sampling. In total, 872 individuals from five rivers (Anambra, Ibbi, Imo, Katsina-Ala and Ogun) were collected and morphometric data taken for ANOVA and multivariate analyses. Standard length (0.969) and post orbital length (0.971) had highest correlation with total length, while anal fin base (0.379) and inter orbital length (0.427) were the least correlated with total length. Multivariate analysis revealed that the Katsina-Ala and Ogun River populations were the most discriminated from the others, based primarily on anal fin base length. Among the meristic characteristics were fin ray counts: dorsal (range 41-48), pectoral (13-17), pelvic 5-7), caudal (12-13), and anal (29-45). Notably, ranges of dorsal and anal fin ray counts observed herein were slightly wider than previously reported. The study revealed significant phenotypic variation to be considered to maximize benefits from future domestication efforts.