Fishery
The narrow sea is home to a unique and rich ecosystem. In addition to a wide range of endemic creatures, such as the critically endangered vaquita, it hosts many migratory species, such as the humpback whale, California gray whale, killer whale, manta ray and leatherback sea turtle, and the world's largest animal, the blue whale. The unusual resident populations of fin whales and sperm whales do not migrate annually. This region has historically been a magnet for world-class sport fishing activities, with a rich history of sporting world records.
The region also has a rich history as a commercial fishery. However, the data vary wildly according to the species being studied, and the Gulf's ability to recuperate after years of overfishing remains uncertain. Moreover, changes in terrestrial ecology, such as the vast reduction in flow from the Colorado River into the Gulf, have negatively affected fisheries, particularly in the northern region.
The Gulf of California sustains a large number of marine mammals, many of which are rare and endangered. Its more than 900 islands are important nesting sites for thousands of seabirds, and its waters are primary breeding, feeding, and nursing grounds for myriad migratory and resident fish species. For decades, the gulf has been a primary source of two of Mexico's leading marine resources, sardines and anchovies. Water pollution is a problem in the Gulf of California, but the more immediate concerns are overfishing and bottom trawling, which destroys eelgrass beds and shellfish.
Efforts by the Mexican government to create conservation zones and nature reserves have been hampered by lack of enforcement resources, as well as a lack of a political consensus on this issue of conservation of the Gulf. This occurs even though significant areas are a UNESCO World Heritage Site. The thousands of miles of coastline are remote and difficult to police, and the politically powerful commercial fishing industry has been slow to embrace even economically viable conservation measures, much less strict measures of conservation. Conservation of the Gulf's fisheries and coastlines is also complicated by a long history of overcapitalization in the sector, and the direct, often negative, impacts that conservation measures have on the livelihoods of Mexico's coastal inhabitants. At present, the Mexican government and business interests have promoted a macro-level, tourist development vision for the Gulf, the impacts of which on local ecology and society are uncertain.
Coastal communities are highly reliant on both commercial and sport fishing, including San Felipe, San Carlos, Sonora, Cabo San Lucas, La Paz, Loreto, Guaymas, Bahia de Kino, Puerto Penasco, Topolobampo and Mulegé. The well-developed shrimp and sardine fleets of Mazatlán, on the Mexican mainland's Pacific coast, heavily exploit the commercial fisheries of the southern Gulf.
Many marine organisms can only survive within a particular salinity range, which makes salinity a notable factor in determining the types of potentially commercial organisms found in the Gulf of California. The mean annual ranges of salinity of the Sea of Cortez are between 3.5 to 3.58% at the surface. Furthermore, the salinity of the water of the Northern Gulf of California is generally higher than the Central and Southern faunal regions due to the increased amount of evaporation that occurs in that region.
Read more about this topic: Gulf Of California