Studies on aspects of the ecology of the catfish Chrysichthys auratus Geoffrey St. Hilaire (Osteichthyes; Bagridae) in the River Benin (Niger Delta, Nigeria)

Abstract

Data on some aspects of the ecology of the catfish Chrysichthys auratus in the Benin river are presented. Fish were captured throughout the year. C. auratus constituted about 63% of the Bagrid catch and favoured the shallow littoral river zone with silty sandy substratum. It attained a total length of 14.6 cm with a weight of 32.0 g. The growth in weight relative to length was isometric and the condition factor ranged from 1.0–2.9. It increased with individual size of fish irrespective of sex and was higher during the wet season than in the dry season. C. auratus fed predominantly in insects, fish and aquatic macrophytes. Crustaceans and algae were a minor part of the diet. It was essentially a night feeder with no clear qualitative variation in feeding habit with size and season. Breeding occurred between May and July and estimates of egg number ranged from 260 to 620. Gonadosomatic index (GSI) values ranged from 2.69 to 19.68.