Dieta y reproducción de Lasiancistrus caucanus (Pisces: Loricariidae) en la cuenca del río La Vieja, Alto Cauca, Colombia

Abstract

Diet and reproduction in Lasiancistrus caucanus (Pisces: Loricariidae) from La Vieja
river basin, Alto Cauca, Colombia. Diet and reproduction habits in Lasiancistrus caucanus from La Vieja
river, Alto Cauca, Colombia, were studied. The sampling was carried out from September 2003 to August 2004
in four secondary drainages, with a width between 3 - 15 meters and mean depth of 1 meter. Its habitat is
principally conformed by kikuyo grass (Poacea) and matandrea (Hedichium coronarium). The dissolved oxygen
and the saturation is high (7.8 mg/l and 91% respectively), pH 7.3. The superficial water temperature reaches
21°C and the air temperature 24.9°C. L. caucanus is a nocturnal species, found adhering to the substrate (rocks
and logs) along the edges of the stream; during the day it is usually captured among a plant called matandrea in
Spanish (Edichium coronarium) but at night it is found in the grass (Poacea). The diet is conformed by algae
that adheres to the substrate, although two insect larvae were found in a stomach. There are differences between
the diets from the different drainages and among fish of different sizes. The spawning was observed between
June-August and October-December. Fecundity was low (185 oocytes) with an average mean egg diameter of 1.5
mm. The sex ratio is 2.6:1, with dominance of females.