Okogwu, O. I. 2011. Age, growth and mortality of Clarias gariepinus (Siluriformes: Clariidae) in the Mid-Cross River-Floodplain ecosystem, Nigeria. Revista da Biología Tropical 59 (4): 1707-1716.
Yalçin, Ş. 2002. Growth of the catfish Clarias gariepinus (Clariidae) in the river Asi (Orontes), Turkey. Cybium 26 (3): 163-172.
Ther is an assessment for this species in Lake Baringo, Kenya done between 2013 and 2014. The abstract is available on this site and the first author as Simon Macharia. Hopefully, they can help you out.