The culture of Clarias gariepinus is getting momentum in Malawi’s aquaculture, yet the fish remain uncharacterized. This study used morphometric measurements to determine the variation between cultured and wild African catfish from Southern Malawi. High phenotypic plasticity was observed between cultured and wild African catfish as the two populations were significantly different in all the measured morphological characteristics except for body depth (p>0.05). African catfish from Domasi Aquaculture Center were found to be significantly different with all the other studied wild populations (Lake Malawi, Lake Malombe and Shire River) except for Lake Chilwa (p>0.05).
The discriminant analysis confirmed that the wild and cultured African catfish are two different population based on the morphological measurements when the discriminant function classified the samples correctly to their groups by 80% and 93% as cultured and wild respectively. The length weight relationship for both wild and cultured African catfish revealed a positive allometric growth with a b-value greater than 3, an indication that fish becomes heavier with increase in length. Further to this, the condition factor was high for
cultured stock than their wild counter parts, an indication of excellent nutrition well-being in the culture environment. However, both stocks had a condition factor greater than 1 which indicated stable physiological state. This is attributed to use of commercial feed in aquaculture which supplements the natural food in the pond. The study concludes that there is need to conduct genetic studies to confirm that the fish stocks classified as morphologically different in this study are distinguishable in their genetic make-up.