Feeding strategy of fish that colonize reservoirs in the Magdalena River basin

Abstract

The construction of dams for hydropower in the Andean rivers of Colombia is leading to a loss of regional fish species. Fish species that persist in these artificial ecosystems are those that find favorable new conditions for their recruitment. Suitable feeding strategies allow these fish to persist and thrive in reservoirs. We analyzed the stomach contents of the species present in two cascade reservoirs in the Magdalena River basin. The objectives were to describe fish diets, determine their feeding strategies, and evaluate if seasonal factors, like rain or spatial distribution, affect the diet of these fish species. Our results indicate that the fish species Brycon henni and Astyanax microlepis feed on a wide range of resources available within the systems and adopt a generalist feeding strategy. Also, opportunistic species such as Roeboides dayi and Hoplosternum magdalenae lived in the reservoirs. The fish species living in the two reservoirs showed different feeding behaviors. The rainy season in these reservoirs was beneficial for opportunistic fish species because it allowed them to diversify their eating behavior. Knowledge of the feeding habits of the studied fish species is a priority for strengthening the environmental management capacity of Andean aquatic resources.