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The Gulf has the highest diversity of large whales in the world, which are legally protected in México. Fourteen of the world’s 32 marine phyla are represented in the Gulf. Its fauna includes nearly 6,000 known macrofaunal species, an estimated half of the actual fauna diversity. Furthermore, its marine beds, 600,000 hectares of coastal lagoons, and 2,560 square kilometers of mangrove forest serve as reproductive, nesting, and nursing sites for hundreds of resident and migratory species. 922 islands are found in the region, which include 90 endemic species, 60 of which are reptilian. Such endemism significantly contributes to make México second in the world in terms of reptile biodiversity.

The most important threats to biodiversity are driven by the growth of economic activities in the region; this growth has caused the deterioration of coastal marine ecosystems due to decreasing freshwater flows, pollution by agrochemicals and urban waste, sedimentation, and the use of inappropriate fishing technologies, such as bottom-trawling nets.

Critical habitat of mangrove forests is being lost at an annual rate of 9 percent from sedimentation, eutrophication, and changes in water flows caused by the construction of shrimp ponds, marinas, inland channels, and deforestation. Invasion of exotic plant and animal species is putting at risk the native and endemic species of the Gulf’s islands and the Sonoran and Baja California Deserts.

An analysis indicates that 127 species that live in the terrestrial ( 88 ) and marine ( 39 ) zone are classified as endangered or threatened by the IUCN Red List. Of these, the endemic Vaquita porpoise (Phocoena sinus) and the Totoaba (Totoaba macdonaldi) are near extinction, while populations of five species of sea turtles have almost disappeared from the Gulf.

In 1997, the International Committee for Vaquita Recovery (CIRVA) for 2004 estimated an average of 567 vaquitas (95% confidence interval). The population size could be even less than was estimated in 1997; ie., 268 vaquitas or 464 for 2004. This new estimate takes into consideration an annual growth rate of 4% and the loss of 39 to 78 individuals per year . This makes the vaquita the most endangered marine cetacean in the world.

Aquaculture, agriculture, and fishing activities are major threats to wetlands biodiversity. Santa María Bay is a specific case where the intensification of shrimp farming has increased demand for land adjacent to the shoreline and has destroyed mangroves in order to build water-intake channels.

In addition, shrimp farms discharge nutrient-laden water from shrimp ponds into the bay, resulting in eutrophication. Increased fishing has resulted in the collapse of some species and has had a direct impact on bird populations, because young birds are used as bait for blue crab fishing.

Agricultural activities represent a threat as agrochemicals are discharged into the bay, although their impact on biodiversity has not been evaluated. As has happened to most coastal lagoons in the Gulf, the two major rivers flowing into the bay have been dammed to divert water for agricultural and urban activities, reducing the amount of freshwater flowing into coastal lagoons to almost nothing. Only agricultural drainage water reaches the bay.

In recent decades, natural resources have been depleted and new opportunities have stimulated demand, resulting in increasing risk of conflict both between and within different business sectors over resource use, especially in the absence of clear property rights and strongly enforced regulations.

Among the greatest threats to the health of the Gulf of California region is poorly planned economic development. Government agencies, academic institutions, private sector, and conservation organizations are addressing these issues by developing several regional initiatives for conserving the Gulf’s richness and providing a basis for sustainable economic development. Two relevant initiatives are: the Coalition for the Sustainability of the Gulf of California, which brought together more than 150 experts to establish regional biodiversity conservation priorities in 2001; and the establishment and operation of five new coastal and marine protected areas.

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