Anthropogenically induced fish diversity reduction in Lake Valencia Basin, Venezuela

Abstract

Lake Valencia in north central Venezuela, one of the largest natural inland bodies of water north of the equator, is undergoing a very rapid deterioration process as a consequence of anthropogenically induced changes. At the Ichthyology Laboratory of Instituto de Zoología Tropical, we have been studying the fishes of the northern tributaries of Lake Valencia since the early 1990's. As a result of collections made in seven northern tributaries of the basin from 1990 to 1993, we have identified 15 species of fish in 6 families. Comparison of our results with those of several authors who have collected in the area since the 1920's, indicate a 59.5%decrease in fish diversity in a 30 year span. The Lake Valencia region has undergone a rapid, considerable industrial and urban growth in recent years. This rapid increment in population size has produced a vast contamination of the lake and its tributaries by activities associated with a growing population. This study will contribute to the understanding of the biodiversity of the region by recording changes in the characteristics of the ichthyofauna in a highly modified environment.