Ontogenetic food resource partitioning and feeding strategy in claroteid catfish, Clarotes laticeps in the lower River Niger

Abstract

Clarotes laticeps is an important commercial food fish of the River Niger. Information on its food niche and feeding strategy could be useful for the rational exploitation and conservation of the species. Ontogenetic diet switch was investigated in samples of C. laticeps caught forthnightly, in the lower River Niger between January 2010 and December 2012. Weight, length and gut weight of captured specimens were taken, and distributed into twelve (12) size categories. Stomach contents were analyzed to determine the frequency of occurrence, weight and total number of dietary items in each dietary category, for each size group. Feeding strategy was graphically determined using the stomach content data. Results revealed that juveniles fed more on immature and adult insects, plant materials, detritus and small crustaceans. Medium size categories fed more on crustaceans, frogs, tadpoles and piscivorous materials. The bigger fishes consumed mostly fish and crustaceans, and showed more specialization in feeding, followed by juveniles. Greater diet breadth was found among the mature medium sizes. The study concludes that food partitioning among different sizes of C. laticeps is a major attribute that could contribute to the survival of the fish population in the lower River Niger.

Keywords: Ontogenetic, resource partitioning, feeding strategy, Clarotes laticeps, River Niger