Editing Gulf of California (section)

==Marine life==
[[File:Giant pacific manta.jpg|left|frame|Giant Pacific [[manta ray]]]]
The narrow sea is home to a rich ecosystem. In addition to a wide range of [[Endemism|endemic]] creatures, such as the critically endangered [[vaquita]] and [[Sea urchins of the Gulf of California|various species of sea urchin]], it also hosts many migratory species, such as the [[humpback whale]], [[Gray whale|California gray whale]], [[killer whale]], [[manta ray]], [[Humboldt squid]] and [[leatherback sea turtle]], and the world's largest animal, the [[blue whale]]. The unusual resident populations of [[fin whale]]s and [[sperm whale]]s do not migrate annually. The area near the Colorado River Delta has a small remnant population of [[totoaba]]. This region has historically been a magnet for world-class [[Recreational fishing|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 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, but the more immediate concerns are overfishing and bottom trawling, which destroys eelgrass beds and shellfish.{{citation needed|date=May 2020}}

Efforts by the Mexican government to create [[Nature conservation|conservation zones]] and [[nature reserve]]s 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.{{Citation needed|date=March 2012}} 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. 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. In 2019, the gulf was added to the [[List of World Heritage in Danger]] because of concerns of the imminent extinction of the [[vaquita]], an [[endemic]] porpoise in the area.<ref name="whs danger">{{cite web |url=https://whc.unesco.org/en/news/1999 |title=The Islands and Protected Areas of the Gulf of California (Mexico) inscribed on the List of World Heritage in Danger |publisher=UNESCO |access-date=8 July 2019}}</ref>

Coastal communities are highly reliant on both commercial and sport fishing, including [[San Felipe, Baja California|San Felipe]], [[San Carlos Nuevo Guaymas|San Carlos]], [[Cabo San Lucas]], [[La Paz, Baja California Sur|La Paz]], [[Loreto, Baja California Sur|Loreto]], [[Guaymas]], [[Bahía Kino]], [[Puerto Peñasco]], [[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.{{citation needed|date=May 2020}}

Many marine organisms can survive only within a particular salinity range, which makes salinity a notable factor in determining the types of potentially commercial organisms found in the gulf. The mean annual ranges of salinity of the Sea of Cortez are between 3.5 and 3.58% at the surface.<ref name="Nix" /> Furthermore, the salinity of the water of the northern gulf is generally higher than the central and southern faunal regions due to the increased amount of evaporation that occurs in that region.<ref name="Brusca" />