The Colorado River Estuary and Upper Gulf of California, Baja, Mexico

Abstract

Since the times of early explorers the Gulf of California has been described as an area of high fertility (Leon-Portilla 1972), owing mainly to tidal mixing and upwelling processes (Alvarez-Borrego et al. 1978).The shallow northernmost part of the Gulf, the Upper Gulf of California, and the Colorado River delta are an area of reproduction and nursery for many fish species (Guevara-Escamilla et al. 1973).They are also habitat for endangered endemic species, like the totoaba (Totoaba macdonaldi) and the small dolphin “vaquita” (Phocoena sinus). In 1993, the Mexican Federal Government decreed the area as a Reserve of the Biosphere (Reserva de la Biosfera del Alto Golfo de California y Delta del Rio Colorado; Fig. 22.1).