Gulf of California

The Gulf of California (also known as the Sea of Cortez, Sea of Cortés (named for Spanish Conquistador Hernán Cortés) or Vermilion Sea; locally known in the Spanish language as Mar de Cortés or Mar Bermejo or Golfo de California) is a marginal sea of the Pacific Ocean that separates the Baja California Peninsula from the Mexican mainland. It is bordered by the states of Baja California, Baja California Sur, Sonora, and Sinaloa with a coastline of approximately 4,000 km (2,500 mi). Rivers which flow into the Gulf of California include the Colorado, Fuerte, Mayo, Sinaloa, Sonora, and the Yaqui. The gulf's surface area is about 160,000 km2 (62,000 sq mi). Depth soundings in the gulf have ranged from fording depth at the estuary near Yuma, Arizona, to in excess of 3,000 meters (9,800 ft) in the deepest parts. [2]

The Gulf is thought to be one of the most diverse seas on the planet, and is home to more than 5,000 species of micro-invertebrates.[3] Home to over a million people, Baja California is the second-longest peninsula in the world, after the Malay Peninsula in Southeast Asia.[2] Parts of the Gulf of California are a UNESCO World Heritage Site.

Gulf of California
Wpdms nasa topo gulf of california
The Gulf of California (highlighted)
Coordinates28°0′N 112°0′W / 28.000°N 112.000°WCoordinates: 28°0′N 112°0′W / 28.000°N 112.000°W
River sourcesColorado, Fuerte, Mayo, Sinaloa, Sonora, and the Yaqui
Ocean/sea sourcesPacific Ocean
Basin countriesMexico
Max. length1,126 km (700 mi)
Max. width48–241 km (30–150 mi)
Surface area160,000 km2 (62,000 sq mi)
Islands37
References[1]
Official nameIslands and Protected Areas of the Gulf of California
TypeNatural
Criteriavii, ix, x
Designated2005
Reference no.1182
State PartyMexico
RegionLatin America and the Caribbean

Geography

Area

The International Hydrographic Organization defines the southern limit of the Gulf of California as: "A line joining Piastla Point (23°38'N) in Mexico, and the southern extreme of Lower California".[4]

The Gulf of California is 1,126 km (700 mi) long and 48–241 km (30–150 mi) wide, with an area of 177,000 km2 (68,000 sq mi), a mean depth of 818.08 m (2,684.0 ft), and a volume of 145,000 km3 (35,000 cu mi).[1]

The Gulf of California includes three faunal regions:

  1. the Northern Gulf of California
  2. the Central Gulf of California
  3. the Southern Gulf of California

One recognized transition zone is termed the Southwestern Baja California Peninsula. Transition zones exist between faunal regions, and they usually vary for each individual species. (Faunal regions are distinguishable based on the specific types of animals found there.[5])

Geology
Gulf of California
Satellite picture of gulf.

Geologic evidence is widely interpreted by geologists as indicating the Gulf of California came into being around 5.3 million years ago as tectonic forces rifted the Baja California Peninsula off the North American Plate.[6] As part of this process, the East Pacific Rise propagated up the middle of the Gulf along the seabed. This extension of the East Pacific Rise is often referred to as the Gulf of California Rift Zone. The Gulf would extend as far as Indio, California, except for the tremendous delta created by the Colorado River. This delta blocks the sea from flooding the Mexicali and Imperial Valleys. Volcanism dominates the East Pacific Rise. The island of Isla Tortuga is one example of this ongoing volcanic activity.[7] Furthermore, hydrothermal vents due to extension tectonic regime, related to the opening of the Gulf of California, are found in the Bahía de Concepción, Baja California Sur.[8]

Islands

The Gulf of California contains 37 major islands – the two largest being Isla Ángel de la Guarda and Tiburón Island. Most of the islands are found on the peninsular side of the gulf. In fact, many of the islands of the Sea of Cortez are the result of volcanic explosions that occurred during the early history of Baja California. The islands of Islas Marías, Islas San Francisco, and Isla Partida are thought to be the result of such explosions. The formations of the islands, however, are not dependent on each other. They were each formed as a result of an individual structural occurrence.[2] Several islands, including Isla Coronados, are home to volcanoes.

The gulf has more than 900 islets and islands which together total about 420 hectares. All of them as a whole were enacted as "Area Reserve and Migratory Bird Refuge and Wildlife" on August 2, 1978. In June 2000, the islands were given a new category "Protection Area Wildlife". In addition to this effort by the Mexican government, for its importance and recognition worldwide, all islands in the Gulf of California are also part of the international program "Man and Biosphere" (MAB) and are part of the World Reserve Network UNESCO Biosphere as Special Biosphere Reserve. Due to the vast expanse covered by this federal protected area conservation and management is carried out through a system of four regional directorates (one per bordering the Gulf of California state) by way of co-direction. There is a regional directorate in the states of Baja California, Baja California Sur, Sonora and Sinaloa. Notwithstanding the foregoing, the work of direct and indirect conservation is done in the islands is governed by a single Management Program, published in 2000, which is complemented by local and specific management programs (at individuals) archipelagos. The Directorate of Protection Area Wildlife California Gulf Islands (APFF-GCR) in Baja California is responsible for 56 islands located off the coast of the state. These are grouped into four archipelagos: San Luis Gonzaga or Enchanted, Guardian Angel, Bahia de los Angeles and San Lorenzo.[9][10]

Shores and tides

The three general types of shores found in the Gulf of California include rocky shore, sandy beach, and tidal flat. Some of the rich biodiversity and high endemism that characterize the Gulf of California and make it such a hotspot for fishing can be attributed to seemingly insignificant factors, such as the types of rocks that make up a shore. Beaches with softer, more porous rocks (such as Coquina limestone, rhyolites, granite, or diorite) generally have a higher species richness than those with harder, smoother rocks (such as basalt or diabase). Porous rocks will naturally have more cracks and crevices in them, making them ideal living spaces for many animals. The rocks themselves, however, generally need to be stable on the shore for a habitat to be stable. Additionally, the color of the rocks can affect the organisms living on a shore. For example, darker rocks will be significantly warmer than lighter ones, and can deter animals that do not have a high tolerance for heat.[2] The northern Gulf of California experiences tidal ranges of up to 5 m (16 ft). Mixed semidiurnal tides are the norm throughout most of the Gulf.

Estuaries

In the Gulf of California, there are a number of negative estuaries, that is, ones in which the evaporation of seawater is relatively greater than that of the fresh water input. The salinities of these inlets are higher than that of the ocean. The temperatures, poikilothermal, of these negative estuaries also are higher than the general temperature of the Gulf.

It is possible that at one time these estuaries were positive, that is, ones in which the seawater component is diluted; therefore, the water is brackish, with salinity less than that of the ocean.

However, due to human modification of the land use around the Gulf of California and water diversion for municipal and agricultural use, there are no longer many rivers that freely empty into the Gulf of California. The upper Colorado River Delta is one example of a historically major estuary and wetlands ecosystem, that since the 20th century construction of upriver dams and diversion aqueducts on the Colorado River, is now a small ephemeral remnant estuary. The remaining Gulf inlets still are important to several species of fishes, crustaceans, and shellfish that are commercially harvested.[2]

Climate

Air

Even though the shores of the Gulf of California are generally sheltered from the continuous wave shock that is experienced by most other North American shores, storms known as a "chubasco" can cause significant damage to shorelines, despite their brevity.[2]

Ocean

The depth of the water helps to determine its temperature. For example, shallow depths are directly influenced by the local temperature of the air, while deeper waters are less susceptible to changes in air temperature.[2] The temperature of the water in the Gulf of California generally experiences lows of 16 °C (61 °F) in winter and highs of 24 °C (75 °F) in summer. But temperatures can vary greatly in the gulf, and the water is almost always warmer by the coast than the open ocean. For example, the waters surrounding La Paz reach 30 °C (86 °F) in August, while the waters in neighboring city Cabo San Lucas, only reach 26 °C (79 °F).[1][11][12][13]

Occasionally, the northern Gulf of California will go through significantly cold winters. The water in the Northern Gulf can sometimes drop below 8 °C (46 °F), which can lead to a large die-off of marine organisms. The animals most susceptible to the large decrease in water temperature include macroscopic algae and plankton.[2]

Average sea temperatures of Puerto Peñasco[12]
Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
17 °C

63 °F

16 °C

61 °F

17 °C

63 °F

19 °C

66 °F

21 °C

70 °F

23 °C

73 °F

26 °C

79 °F

28 °C

82 °F

28 °C

82 °F

26 °C

79 °F

23 °C

73 °F

19 °C

66 °F

Average sea temperatures of La Paz[11]
Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
19 °C

66 °F

19 °C

66 °F

21 °C

70 °F

23 °C

73 °F

25 °C

77 °F

27 °C

81 °F

28 °C

82 °F

30 °C

85 °F

28 °C

82 °F

27 °C

81 °F

24 °C

75 °F

21 °C

70 °F

Average sea temperatures of Cabo San Lucas[14]
Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
20 °C

68 °F

19 °C

66 °F

19 °C

66 °F

19 °C

66 °F

20 °C

68 °F

21 °C

70 °F

24 °C

75 °F

26 °C

79 °F

26 °C

79 °F

26 °C

79 °F

24 °C

75 °F

22 °C

72 °F

Marine life

Giant pacific manta
Giant Pacific manta ray

The narrow sea is home to a 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, Humboldt squid 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. The area near the delta of the Colorado river has a small remnant population of the totoaba fish. 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, 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.

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 and 3.58% at the surface.[1] 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.[2]

See also

Further reading

  • Brusca, Richard C. (Editor) (2010). The Gulf of California: Biodiversity and Conservation. University of Arizona Press. pp. 354 pages.CS1 maint: Extra text: authors list (link) Studies by researchers, on both sides of the border, on the threats to the diversity of species in the gulf's waters.

References

  1. ^ a b c d Rebekah K. Nix. "The Gulf of California: A Physical, Geological, and Biological Study" (PDF). University of Texas at Dallas. Retrieved April 10, 2010.
  2. ^ a b c d e f g h i Richard C. Brusca (1973). A Handbook to the Common Intertidal Invertebrates of the Gulf of California. Tucson, Arizona: University of Arizona Press. pp. 10–15. ISBN 978-0-8165-0356-8.
  3. ^ Ernesto Campos, Alma Rosa de Campos & Jesús Angel de León-González (2009). "Diversity and ecological remarks of ectocommensals and ectoparasites (Annelida, Crustacea, Mollusca) of echinoids (Echinoidea: Mellitidae) in the Sea of Cortez, Mexico". Parasitology Research. 105 (2): 479–487. doi:10.1007/s00436-009-1419-8. PMID 19337754.
  4. ^ "Limits of Oceans and Seas, 3rd edition" (PDF). International Hydrographic Organization. 1953. p. 35.
  5. ^ "The Gulf of California Invertebrate Database: The Invertebrate Portion of the Macrofauna Golfo Database". Arizona-Sonora Desert Museum: Center for Sonoran Desert Studies.
  6. ^ Hamilton, W.B., 1961, Origin of the Gulf of California: GSA Bull., 72, 1307–1318.
  7. ^ "Science Plans RCL". review.nsf-margins.org. Retrieved May 27, 2008.
  8. ^ Leal-Acosta, M.L., Prol-Ledesma, R.M. (2016). "Caracterización geoquímica de las manifestaciones termales intermareales de Bahía Concepción en la Península de Baja California" (PDF). Boletín de la Sociedad Geológica Mexicana (in Spanish). 68 (3): 395–407.CS1 maint: Multiple names: authors list (link)
  9. ^ "Valle de los Cirios. Tesoro de Baja California". 14 July 2010.
  10. ^ "Área de Protección de Flora y Fauna Islas del Golfo de California en Baja California".
  11. ^ a b [1] Archived December 21, 2011, at the Wayback Machine
  12. ^ a b "Archived copy". Archived from the original on 2012-07-15. Retrieved 2012-06-12.CS1 maint: Archived copy as title (link)
  13. ^ "Marine Biology of Baja California". Math.ucr.edu. Retrieved 2013-12-08.
  14. ^ "San Jorge Water Temperature (Sea) and Wetsuit Guide (Baja Sur, Mexico)". Surf-forecast.com. Retrieved 2013-12-08.

External links

Baja California

Baja California (Spanish pronunciation: [ˈbaxa kaliˈfoɾnja] (listen), English: Lower California), officially the Free and Sovereign State of Baja California (Spanish: Estado Libre y Soberano de Baja California), is a state in Mexico. It is the northernmost and westernmost of the 32 Federal Entities of Mexico. Before becoming a state in 1952, the area was known as the North Territory of Baja California (El Territorio Norte de Baja California). It has an area of 70,113 km2 (27,071 sq mi), or 3.57% of the land mass of Mexico and comprises the northern half of the Baja California Peninsula, north of the 28th parallel, plus oceanic Guadalupe Island. The mainland portion of the state is bordered on the west by the Pacific Ocean, on the east by Sonora, the U.S. state of Arizona, and the Gulf of California (also known as the "Sea of Cortez"), and on the south by Baja California Sur. Its northern limit is the U.S. state of California.

The state has an estimated population of 3,315,766 (2015) much more than the sparsely populated Baja California Sur to the south, and similar to San Diego County, California on its north. Over 75% of the population lives in the capital city, Mexicali, in Ensenada, or in Tijuana. Other important cities include San Felipe, Rosarito and Tecate. The population of the state is composed of Mestizos, mostly immigrants from other parts of Mexico, and, as with most northern Mexican states, a large population of Mexicans of Spanish ancestry, and also a large minority group of East Asian, Middle Eastern and indigenous descent. Additionally, there is a large immigrant population from the United States due to its proximity to San Diego and the lower cost of living compared to San Diego. There is also a significant population from Central America. Many immigrants moved to Baja California for a better quality of life and the number of higher paying jobs in comparison to the rest of Mexico and Latin America.

Baja California is the twelfth largest state by area in Mexico. Its geography ranges from beaches to forests and deserts. The backbone of the state is the Sierra de Baja California, where the Picacho del Diablo, the highest point of the peninsula, is located. This mountain range effectively divides the weather patterns in the state. In the northwest, the weather is semi-dry and mediterranean. In the narrow center, the weather changes to be more humid due to altitude. It is in this area where a few valleys can be found, such as the Valle de Guadalupe, the major wine-producing area in Mexico. To the east of the mountain range, the Sonoran Desert dominates the landscape. In the south, the weather becomes drier and gives way to the Vizcaino Desert. The state is also home to numerous islands off both of its shores. In fact, the westernmost point in Mexico, the Guadalupe Island, is part of Baja California. The Coronado, Todos Santos and Cedros Islands are also on the Pacific Shore. On the Gulf of California, the biggest island is the Angel de la Guarda, separated from the peninsula by the deep and narrow Canal de Ballenas.

Baja California Peninsula

The Baja California Peninsula (English: Lower California Peninsula, Spanish: Península de Baja California) is a peninsula in Northwestern Mexico. It separates the Pacific Ocean from the Gulf of California. The peninsula extends 1,247 km (775 miles) from Mexicali, Baja California in the north to Cabo San Lucas, Baja California Sur in the south. It ranges from 40 km (25 miles) at its narrowest to 320 km (200 miles) at its widest point and has approximately 3,000 km (1,900 miles) of coastline and approximately 65 islands. The total area of the Baja California Peninsula is 143,390 km2 (55,360 sq mi).

The peninsula is separated from mainland Mexico by the Gulf of California and the Colorado River. There are four main desert areas on the peninsula: the San Felipe Desert, the Central Coast Desert, the Vizcaíno Desert and the Magdalena Plain Desert.

Baja California Sur

Baja California Sur (Spanish pronunciation: [ˈbaxa kaliˈfoɾnja suɾ] (listen), English: "South Lower California"), officially the Estado Libre y Soberano de Baja California Sur (English: Free and Sovereign State of South Lower California), is the second-smallest Mexican state by population and the 31st admitted state of the 31 states which, with Mexico City, make up the 32 Federal Entities of Mexico.

Before becoming a state on 8 October 1974, the area was known as the El Territorio Sur de Baja California ("South Territory of Baja California"). It has an area of 73,909 km2 (28,536 sq mi), or 3.57% of the land mass of Mexico, and occupies the southern half of the Baja California Peninsula, south of the 28th parallel, plus the uninhabited Rocas Alijos in the Pacific Ocean. It is bordered to the north by the state of Baja California, to the west by the Pacific Ocean, and to the east by the Gulf of California, or the "Sea of Cortés". The state has maritime borders with Sonora and Sinaloa to the east, across the Gulf of California.

The state is home to the tourist resorts of Cabo San Lucas and San José del Cabo. Its largest city and capital is La Paz.

Brawley Seismic Zone

The Brawley Seismic Zone (BSZ), also known as the Brawley fault zone, is a predominantly extensional tectonic zone that connects the southern terminus of the San Andreas Fault with the Imperial Fault in Southern California. The BSZ is named for the nearby town of Brawley in Imperial County, California, and the seismicity there is characterized by earthquake swarms.

Colorado River Delta

The Colorado River Delta is the region where the Colorado River flows into the Gulf of California (also known as the Sea of Cortez). The delta is part of a larger geologic region called the Salton Trough. Historically, the interaction of the river's flow and the ocean's tide created a dynamic environment, supporting freshwater, brackish, and saltwater species. Within the delta region, the river split into multiple braided channels and formed complex estuary and terrestrial ecosystems. Use of water upstream and the accompanying reduction of fresh water flow has resulted in loss of most of the wetlands of the area, as well as drastic changes to the aquatic ecosystems. However, a scheme is currently in place which aims to rejuvenate the wetlands by releasing a pulse of water down the river delta.

Disparate angelshark

The disparate angelshark (Squatina heteroptera) is a species of angelshark. It occurs at depths down to 164 m in the Gulf of Mexico and reaches a length of 49 cm (19 in). Heteroptera in its name refers to the difference in size, shape and area of the two dorsal fins.

Filetail catshark

The filetail catshark (Parmaturus xaniurus) is an Eastern Pacific endemic deepwater catshark ranging from Oregon to the Gulf of California. Adults are epibenthic and found near areas of rocky vertical relief over soft mud bottoms on the outer continental shelf and upper slope at depths of 91 to 1,251 m, juveniles are mesopelagic, found around 500 m off the bottom in waters over 1,000 m deep. Reaches a maximum size of 60 cm TL. An oviparous species, females deposit eggcases throughout the year with concentrated reproductive output July through September. There is no information available on the age and growth, longevity, fecundity, abundance or mortality of this species. It is not targeted by commercial fisheries or utilized for human consumption, but is known to be incidental catch in longline and bottom trawl fisheries, although no specific data is available.

Gran Desierto de Altar

The Gran Desierto de Altar is one of the major sub-ecoregions of the Sonoran Desert, located in the State of Sonora, Northwest Mexico. It includes the only active erg dune region in North America. The desert extends across much of the northern border of the Gulf of California, reaching more than 100 kilometres (62 mi) east to west, and over 50 kilometres (31 mi) north to south. It constitutes the largest continuous wilderness area within the Sonoran Desert.

The eastern portion of the area contains the volcanic Pinacate Peaks region, and with the western Gran Desierto de Altar area, together they form the El Pinacate y Gran Desierto de Altar Biosphere Reserve and a UNESCO World Heritage Site.

Gulf of California Rift Zone

The Gulf of California Rift Zone (GCRZ) is the northernmost extension of the East Pacific Rise which extends some 1,300 km (800 mi) from the mouth of the Gulf of California to the southern terminus of the San Andreas Fault at the Salton Sink.

The GCRZ is an incipient rift zone akin to the Red Sea Rift. In the GCRZ continental crust originally associated with the North American Plate has been pulled apart by tectonic forces and is being replaced by newly formed oceanic crust and seafloor spreading. The rifting has resulted in the transfer of the Baja California Peninsula to the Pacific Plate.

La Paz, Baja California Sur

La Paz (pronounced [la ˈpas] (listen), Peace) is the capital city of the Mexican state of Baja California Sur and an important regional commercial center. The city had a 2015 census population of 244,219 inhabitants, making it the most populous city in the state. Its metropolitan population is somewhat larger because of the surrounding towns, such as El Centenario, Chametla and San Pedro. It is in La Paz Municipality, which is the fourth-largest municipality in Mexico in geographical size and reported a population of 290,286 inhabitants on a land area of 20,275 km2 (7,828 sq mi).The population of La Paz has grown greatly since the 2000s. The growth is largely because the city has one of the highest standards of living and quality of life in Mexico. Many workers migrate to La Paz and other areas in Baja California Sur.

La Paz is served by the Manuel Márquez de León International Airport with flights to the most important cities of Mexico: Mexico City, Guadalajara, Monterrey. Airlines flying into La Paz include Aeroméxico Connect, Volaris and VivaAerobus. Two ferry services operate from the port of Pichilingue outside the city, connecting the Baja California peninsula to the mainland at Mazatlán and Topolobampo, near Los Mochis.

Lollipop catshark

The lollipop catshark (Cephalurus cephalus) is a little-known species of deep sea catshark, belonging to the family Scyliorhinidae, and the only described member of its genus. A diminutive, bottom-dwelling shark of the outer continental shelf and upper continental slope, this species can be readily identified by its tadpole-like shape with a greatly expanded, rounded head and narrow body. The large head houses expanded gills, which are thought to be an adaptation for hypoxic conditions. This shark preys on crustaceans and fishes. Reproduction is aplacental viviparous, with females retaining egg cases internally two at a time until they hatch. There is no fishery interest in this species, and the International Union for Conservation of Nature (IUCN) lacks sufficient information to assess its conservation status.

Longnose catshark

The longnose catshark (Apristurus kampae) is a catshark of the family Scyliorhinidae found in the eastern central Pacific from central and southern California and the Gulf of California, between latitudes 38° N and 23° N, at depths down to 1,890. Its length is up to 58 cm.

Lower Colorado River Valley

The Lower Colorado River Valley ("LCRV") is the river region of the lower Colorado River of the southwestern United States in North America that rises in the Rocky Mountains and has its outlet at the Colorado River Delta in the northern Gulf of California in northwestern Mexico, between the states of Baja California and Sonora. This north–south stretch of the Colorado River forms the border between the U.S. states of California/Arizona and Nevada/Arizona, and between the Mexican states of Baja California/Sonora.

It is commonly defined as the region from below Hoover Dam and Lake Mead to its outlet at the northern Gulf of California (Sea of Cortez); it includes the Colorado River proper, canyons, the valley, mountain ranges with wilderness areas, and the floodplain and associated riparian environments. It is home to recreation activities from the river, the lakes created by dams, agriculture, and the home of various cities, communities, and towns along the river, or associated with the valley region. Five Indian reservations are located in the LCRV: the Chemehuevi, Fort Mojave and Colorado River Indian Reservations; at Yuma are the Quechan and Cocopah reservations.

Methanopyrus

In taxonomy, Methanopyrus is a genus of the Methanopyraceae.Methanopyrus is a genus of methanogen, with a single described species, M. kandleri. It is a hyperthermophile, discovered on the wall of a black smoker from the Gulf of California at a depth of 2000 m, at temperatures of 84–110 °C. Strain 116 was discovered in black smoker fluid of the Kairei hydrothermal field; it can survive and reproduce at 122 °C. It lives in a hydrogen-carbon dioxide rich environment, and like other methanogens reduces the latter to methane. It is placed among the Euryarchaeota, in its own class.

Peppered catshark

The peppered catshark (Galeus piperatus) is a common but little-known species of catshark, part of the family Scyliorhinidae, inhabiting depths of 130–1,326 m (427–4,350 ft) in the northern Gulf of California. It is found on or near the ocean floor, and conducts seasonal migrations, spending winter in deeper water. Reaching a length of 37 cm (15 in), this species has a slender grayish body with a fine covering of black dots. On the dorsal edge of its caudal fin is a prominent crest of enlarged dermal denticles. It is oviparous, with the reproductive period probably lasting from May to September. The International Union for Conservation of Nature (IUCN) has listed the peppered catshark under Least Concern, as it faces no significant threats from human activity.

Scoophead

The scoophead (Sphyrna media) is a little-known species of hammerhead shark, part of the family Sphyrnidae. It inhabits the tropical waters of the western Atlantic Ocean, from Panama to southern Brazil, and in the eastern Pacific Ocean from the Gulf of California to Ecuador, and probably northern Peru, as well. It is found in shallow, inshore habitats.One of the smaller hammerheads, the scoophead measures 150 cm long; adult males measure 90 cm long and adult females 100–133 cm. It is distinguished by its moderately broad, mallet-shaped head (22–33% as wide as the body is long). The forward margin of the head is arched, with weak medial and lateral indentations and no prenarial grooves, traits that this species shares with the scalloped bonnethead (Sphyrna corona). It is distinguished from the scalloped bonnethead by its shorter snout, broadly arched mouth, and deeply concave anal fin. The first dorsal fin is moderately falchate, and the second dorsal fin is as tall as the anal fin. The pelvic fins are not falchate, with a straight to moderately concave rear margin. Its coloration is grey-brown above, light below, with no fin markings.Off the coast of Trinidad, the scoophead coexists with two other small hammerheads, the bonnethead (Sphyrna tiburo) and the golden hammerhead (S. tudes). These species avoid competition by diet and habitat differences; the scoophead feeds on small elasmobranchs, octopus, squid, and flounders. Like other hammerheads, the scoophead is viviparous, with the pups measuring 34 cm or less at birth. It is taken with bottom longlines, gillnets, and hook and line throughout its range. It is caught commercially and sold as fresh fish or turned into fishmeal. The scoophead is also a common bycatch of the gillnet mackerel fishery off Trinidad.

Sebastián Vizcaíno

Sebastián Vizcaíno (1548–1624) was a Spanish soldier, entrepreneur, explorer, and diplomat whose varied roles took him to New Spain, the Philippines, the Baja California peninsula, the California coast and Japan.

Sonoran Desert

The Sonoran Desert (Spanish: Desierto de Sonora) is a North American desert which covers large parts of the Southwestern United States in Arizona and California and of Northwestern Mexico in Sonora, Baja California, and Baja California Sur. It is the hottest desert in Mexico. It has an area of 260,000 square kilometers (100,000 sq mi). The western portion of the United States–Mexico border passes through the Sonoran Desert.

In phytogeography, the Sonoran Desert is within the Sonoran Floristic Province of the Madrean Region in southwestern North America, part of the Holarctic Kingdom of the northern Western Hemisphere. The desert contains a variety of unique and endemic plants and animals, such as the saguaro (Carnegiea gigantea) and organ pipe cactus (Stenocereus thurberi).

Vaquita

The vaquita (Spanish: [baˈkita]; Phocoena sinus) is a species of porpoise endemic to the northern part of the Gulf of California that is on the brink of extinction. Based on beached skulls found in 1950 and 1951, the scientific description of the species was published in 1958. The word vaquita is Spanish for "little cow". Other names include cochito (Spanish for "little pig"), desert porpoise, vaquita porpoise, Gulf of California harbor porpoise, Gulf of California porpoise, and gulf porpoise. Since the baiji (Lipotes vexillifer) is thought to have gone extinct in 2006, the vaquita has taken on the title of the most endangered cetacean in the world. It has been listed as critically endangered since 1996. The population was estimated at 600 in 1997, below 100 in 2014, approximately 60 in 2015, around 30 in November 2016, and only 12-15 in March 2018, leading to the conclusion that the species will soon be extinct unless drastic action is taken.The population decrease is largely attributed to bycatch from the illegal gillnet fishery for the totoaba, a similarly sized endemic drum that is also critically endangered. The population decline has occurred despite an investment of tens of millions of dollars by the Mexican government in efforts to eliminate the bycatch. A partial gillnet ban was put in place for two years in May 2015; its scheduled expiration at the end of May 2017 spurred a campaign to have it extended and strengthened. On 7 June 2017, an agreement was announced by Mexican president Enrique Peña Nieto to make the gillnet ban permanent and strengthen enforcement. As well as the Mexican government and various environmental organizations, this effort will now also involve the foundations of Mexican businessman Carlos Slim and American actor and environmental activist Leonardo DiCaprio.A protective housing/captive breeding program, unprecedented for a marine mammal, has been developed and is undergoing feasibility testing, being now viewed as necessary to rescue the species. However, the sea pen housing needed to implement this strategy is not expected to be available until October 2017, which is feared may be too late. Additionally, the ability of the vaquita to survive and reproduce while confined to a sanctuary is uncertain. The Mexican government approved the plan on 3 April 2017, with commencement projected to begin in October 2017.

In November 2017, the attempt to capture wild vaquitas for captive breeding and safekeeping was suspended following the death of a female vaquita. The adult female died within hours of being captured. In December 2017, Mexico, the United States and China agreed to take further steps to prevent trade in totoaba bladders. However, the intensifying poaching and the extremely low population make it likely that the species will go extinct unless drastic measures are taken. If the species does go extinct, it will likely be the first cetacean to do so since the baiji.

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