Trophic Ecology and Establishment of the Silver Catfish, Chrysichthys nigrodigitatus (Pisces: Siluriformes: Claroteidae) Introduced in an Artificial Pond of Benin, West Africa

Abstract

Background and Objective: The trophic ecology of the silver catfish, Chrysichthys nigrodigitatus (Lacépède, 1803) was examined to evaluate resource exploitation and utilization and the establishment of this highly priced species, introduced in the man-made lake (pond) of Ahozon (South-Benin). Methodology: Chrysichthys nigrodigitatus individuals were sampled monthly in both open water and aquatic vegetation habitats from August, 2014 to October, 2015 and stomach contents were evaluated on each specimen collected. Results: The eco-morphological patterns depicted along with dietary analysis showed that C. nigrodigitatus is an opportunistic benthic feeder foraging mainly on aquatic insects (59.9%), substrate particles (11.76%), detritus (9.18%), seeds (5.51%) and algae (4.97%). High niche breadths ranging between 0.55-8.35 were recorded and niche overlaps (0.39 <0.98) between size classes indicated ontogenetic diet shifts. The trophic plasticity behavior of this claroteid and the broad range of preys ingested, led to active spawning and high colonization that indicated the successful establishment of C. nigrodigitatus in lake Ahozon. Conclusion: The success of fisheries and its sustainable exploitation require a holistic approach of lake management including the prevention of domestic waste dumping, the protection of spawning and foraging grounds, the planned harvest of the fish stock, the protection of lake’s margin to avoid erosion and the periodic ecological monitoring of lake Ahozon.