Instituto de Ciencias Naturales, Universidad Nacional de Colombia. Bogotá, Colombia.

Abstract

  The Magdalena River Basin is the most important region of Colombia in terms of development and economy. About 80% of its population lives in this basin and traditionally its waters have produced more than 60% of fish consumed in the country. Nonetheless, from a production of nearly 80,000 ton yr^-1 in the 1970s, currently those fisheries produce only one tenth of that amount. This paper analyzes the different reasons of this collapse, and concludes that the causes are social, due to over fishing by landless displaced peasants trying to survive as fishermen.