Ictiofauna de la Laguna Yahuarcaca y aspectos tróficos y reproductivos de cinco especies predominantes, Leticia - Colombia

The Amazon River floodplains are highly productive pulsing systems from an ecological point,due mostly to the periodic inflow of sediments that are dragged from the Andes by the rivers.In Colombia, this Amazon systems have not been intensely studied, therefore, this study tookplace in an floodplain lake of the Amazon river near the city of Leticia. Ichthyological sampleswere taken at four different times during a year according to the Amazon water level, ascendantwaters (April), high waters (June), descendant waters (July) and low waters (November), inorder to study the variation of fish over time and to create a reference collection of theYahurcaca lake. 134 species were found 54 of which are new reports for the Colombian Amazonregion. The fish community changes its composition and relative abundance throughoutthe periods studied, due to changes in resources related with the hydric pulse. The changes inthe diet during the different periods was analyzed for five predominant species: Triportheus albus,Triportheus angulatus, Triportheus elongatus(Characidae), Rhytiodus microlepisy Schizodon fasciatus(Anostomidae). The Triportheusspecies have a generalized feeding strategy and prefer terrestrialinsects, fish pieces, fruits and seeds. The two anostomids are clearly specialists and feed mostlyof vegetal material from autochthonous or alochthonous origin. In all the species the type andamount of food was different in each period, due to the variation in the resources offer whichrelates with the hydric pulse. The examination of the gonads of the species, suggests that all ofthem have one posture per year, because no mature females were found in any of the periodsanalyzed. Possibly the spawning occurs in the first months of the year, time when the water level begins to rise and floods the lake. The species would present high fecundity because even inimmature stages a high number of eggs was observed. The type and amount of feedingresources, the reproductive strategy and the time of spawning of the fishes are closely relatedwith the fluctuations of Yahuarcaca’s waterlevel, ultimately with the hydric pulse