ENVIRONMENTAL AUDITING; Change in Fish Fauna as Indication of Aquatic Ecosystem Condition in Rio Grande de Morelia-Lago de Cuitzeo Basin, Mexico

摘要

The Rio Grande de Morelia-Lagio de Cuitzeo basin in west central mexico has experienced major increases in water pollution from a rapidly growing human population. We examined changes in the long-term distribution of fishes in rlation to wter quality and quantitiy in order to assess the condition and health of aquatic ecosystems in the basin. Sampling between 1985 and 1993 revealed that five (26/100) of thue 19 native fish species known from the basin had been extirpated. Two of these were endemics, Chirostoma chararian C.