Incidental bycatch by ornamental fishing during the low-water season in the influence zone of Puerto Carreño, Colombian Orinoco Basin

Abstract

Objective. The present study assesses the incidental fish catches in the fishing of ornamental species in terms of richness and abundance within the influence zone of Puerto Carreño, Vichada, Colombia. Materials and methods. Samplings were carried out in the Orinoco River and Bita River and Caño Negro stream during the low-water season, in March and April of 2007. Target and incidental species collected during the ornamental fishing totalized 152. Catches per unit of effort (CPUE) as well as the percentage composition of fish catches of target vs. incidental species were estimated. Results. The highest values of CPUE of fishes with ornamental value correspond to: Dicrossus maculatus, Hemigrammus rodhostomus, Corydoras cf. melanistius, Peckoltia sp. 2 and Hemiancistrus sp., and the highest values of incidental species were for: Hemigrammus sp., Moenkhausia sp., Hemigrammus levis, Aphanothorulus cf. ammophilus, Triportheus sp. y Moenkhausia lepidura. The richness percentage of incidental species varied between 92% and 98%. However the abundance percentage of target species was always higher than the percentage of incidental catches varying between 73% and 83% with the exception of that obtained in the fisheries of the Orinoco River outcrops that was 17%. Conclusions. The impact of the fishing ornamental fish on species taught incidentally is seen mainly at the level of richness, but not at the level of abundance.