Objectives.

The reproductive and trophic ecology of Bryconamericus caucanus was analyzed in la Venada creek, Quindío river, Alto Cauca, Colombia.

Materials and methods.

Individuals were collected between January and December 2013. Multivariate analyses were performed to compare the trophic characteristics of the species between climatic periods (wet and dry), sexes, and sexual maturity (juvenile and adults). We also analyzed the condition factor (K) and the numerical (%N), volumetric (%V), and frequency (%Fo) percentages for each prey. We tested for deviations in the sex proportion using chi-squared tests and we also estimated the Gonodosomatic Index (GSI) and absolute fecundity (Fa).

Results.

A total of 162 individuals (SL: 40-75 mm) were here analyzed. B. caucanus is an insectivorous fish (86.47% IRI) that mainly feeds on the orders Ephemeroptera (Baetidae; 27.71%), Hymenoptera (Formicidae; 23.57%), Diptera (Simuliidae 17.36%; Chironomidae 9.79%), and Trichoptera (Hydropsychidae; 8.04). Multivariate analyses showed differences between climatic periods, with the lowest richness occurring during dry season. Between sexes, females showed the widest trophic niche. Adults, on the other hand, showed a wider trophic niche than juveniles. The species has two reproductive peaks during rainy seasons which are also related to the increase in the trophic richness during the same periods (March-April, September-November).

Conclusions.

We found that B. caucanus has an incipient trophic differentiation between ontogenic stages and sexes. Trophic differences are remarkable between climatic periods. The two spawning periods for the species occur during the beginning of the wet seasons (March-April, September-November).

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