Morphometry and feeding ecology of Heterobranchus longifilis (Valenciennes, 1840) in River Okura, Kogi Central, Nigeria

Abstract

The body morphometry and feeding ecology of the African catfish, Heterobranchus longifilis (Valenciennes, 1840) was studied from October 2011 to October 2012. Morphometric characters used for the study include the body weight, standard and gut lengths. Classification of food items was by ecotype classification. The regression of body standard length against the body weight of fish samples gave the equation Log1.55+2.76LogL with mean condition factor of 1.2 ± 0.3. Out of 254 gut content analyzed, 94.9% had food in their stomachs in varying degrees, suggesting high feeding activity of the species in River Okura. H. longifilis was an omnivore, feeding on food type I namely Nekton, zoobenthos and others, such as unidentified insects and palm fruits. It consumed mostly finfish and shell fish making it tend towards carnivory. The relative gut length ranged from 13.92cm (standard length 17.4cm, body weight 74.5g) to 108.8cm (standard length 68.0cm, body weight 3800g). The mean condition factor is greater than one suggesting that the fish species fared well in River Okura even though negative growth allometry of 2.76 was observed.