Gulf of California

The Gulf of California, located between the Baja California peninsula and mainland Mexico, is home to an abundant array of land and marine animals and plant life. However, overfishing and industrial runoff have led to environmental problems that threaten to destroy the region's ecological balance. Some of the Gulf was designated a United Nations Educational, Scientific and Cultural Organization (UNESCO) World Heritage Site to protect what is seen as one of the world's most ecologically diverse marine habitats.

Geography and Geology

The Gulf of California, also known as the Sea of Cortez, lies north of the Tropic of Cancer between the east coast of the Baja California peninsula and the west coast of Mexico. The Mexican states of Sonora and Sinaloa on the country’s mainland are located on the Gulf’s eastern shore. To the north, a narrow strip of the Mexican states of Baja California North and Sonora separates the Gulf from the southwestern US states of California and Arizona. The mouth of the Colorado River is located on the northern reaches of the Gulf. The Mexican states of Baja California North and Baja California South lie to the west of the Gulf. The Pacific Ocean borders its southern reaches.

Geologists estimate that the Gulf originated more than 4 million years ago, due to a clash of tectonic plates that caused the Baja California peninsula to drift westward from Mexico’s mainland. The area now containing the Gulf subsided, allowing ocean water to flow in from the south.

The Pacific Ocean interacts continuously with the Gulf waters. As the ocean tide rises, seawater floods into it. As it recedes, the water level in the Gulf also drops. The tide surge is most noticeable in the north, where the incoming tide floods the surrounding lowlands for miles inland and then departs, leaving miles of sandy beaches and mud flats rich with sea life. The most extreme wave action occurs twice per lunar month, with the advent of the new and full moons.

Over one hundred islands dot the Gulf. Most are barren, and few have a supply of potable water. As a result, wildlife is scarce and is limited to only a few of the larger islands. Only three have any human habitation: San José and Isla del Carmen have colonies of salt mine workers, and San Marcos contains a contingent of employees of a gypsum mining operation.

The weather in the Gulf remains fairly constant. The occasional storms are mild compared to those found in the Pacific Ocean. More tempestuous storms, called chubascos, occasionally threaten the small boats on the Gulf’s waters. Local currents also threaten the watercraft. The islands of the Salsepuedes group, two-thirds of the way north from the ocean entrance, present a hazardous area to sailors regarding local currents. Temperature can also be a danger. In the mid-summer, especially in July and August, temperatures on the Gulf often reach an uncomfortable 38 degrees Celsius (100 degrees Fahrenheit).

The Colorado River, for millennia, fed its waters into the Gulf. At the beginning of the twentieth century, humans interrupted this natural process by erecting a series of dams and canals along the river’s course. Although some freshwater does flow into the Gulf from underground sources, in the twenty-first century, the Colorado River delivers only a relative trickle of surface water to the Gulf of California. The river’s output is heavily loaded with pesticides, fertilizers, and human waste as well. The dam system has also reduced the amount of sediment that flows into the Gulf, which has resulted in a decline in the amount of nutrients fed into the Gulf’s waters, an important part of the food chain that supports such a wide variety of marine life.

Marine Life

The Gulf of California’s outstanding characteristic lies in the quality and quantity of its sea life. The diversity of its marine occupants varies from great whales to plankton, tiny invertebrates that serve as the basic food source for the Gulf’s feeders. Its open access to the Pacific promotes a constant interchange of a wide variety of species between the two bodies of water.

Huge fin whales, the second largest whale species, travel well up into the Gulf. Once thought to be on the verge of extinction, the gray whale migrates from its home in Alaska to Scammon Lagoon on the Pacific side of the peninsula. At Scammon, the female gray whales give birth to their offspring. During their annual pilgrimage south, the gray whale migration is now a common sight along the shores of Washington, Oregon, and California. The Gulf is also home to many other mammals. Dolphins, porpoises, orcas, and sea lions have taken up residence. There is an ample food supply within the Gulf for all species. Huge turtles are found in the north, although their popularity as a dish for human consumption threatens their long-term survival.

There are thirty different types of sharks among the estimated 650 different species of fish in the Gulf. Lower on the food chain, in addition to the plankton, a variety of clams, mussels, starfish, flatworms, and sea anemones make their home in the mud flats and shallow pools surrounding the Gulf. Overhead, huge flights of birds hunt continuously for marine prey. The Gulf is a living biological museum. However, increasing human activity in the area has threatened the vitality of this ecosystem.

History

Cultural anthropologists believe that humans first settled in the area surrounding the sea as much as ten thousand years ago. The area's abundant seafood and small land animals, coupled with its temperate climate, would have been attractive to settlers. Sites uncovered by archaeologists reveal that the Gulf’s early human inhabitants had a simple social organization. The temperate weather obviated the need for either protective clothing or permanent shelter. They used only the most basic tools and occupied themselves with gathering food rather than growing it.

In 1535, a Spanish expedition organized by Hernán Cortés, the conqueror of Mexico, landed at La Paz, now a port on Baja California’s southeastern shore. The Spaniards' plan to establish a permanent colony there failed when conflicts with the local natives broke out. As had been the case with other Spanish expeditions, an attempt by the explorers to exploit or enslave the Indigenous peoples caused the fight.

A more sympathetic group of Spaniards arrived at the Gulf about 150 years later. Jesuit missionaries landed at Loreto, farther up Baja’s east coast, to establish Spain’s first permanent colony in the area. The Jesuits sought to build a string of missions throughout the largely barren peninsula. They erected some thirty-five churches at one time or another in Baja, California, but most failed to last. In most cases, water shortages proved to be insurmountable. In the twenty-first century, because of its aridity, most of the peninsula remains sparsely populated.

Economy

People living along the Gulf of California today depend on fishing, tourism, and some cattle raising, farming, and mining for their economic well-being. The principal cities, especially those on the Baja peninsula, reflect this. Only in the twenty-first century has the Mexican government taken an active role in the Gulf’s development.

Numerous ports on the Baja peninsula and the Mexican mainland surround the Gulf. Many of the peninsula’s economic necessities must be imported from the Mexican mainland or the United States, and many needed imports arrive by sea. There are six key harbors on the Gulf’s western reaches and five on the Mexican mainland side.

San Felipe, in Baja California North, is the Gulf’s northernmost facility. The small village has become a popular destination for anglers of all types and tourists from the United States and elsewhere. The tremendous tidal surge in the area allows boat owners to beach their craft during one of the monthly high tides. When the water recedes, the boats are left high and dry for both minor and major repairs and maintenance. The craft can then be launched easily at the next high tide. Santa Rosalía, in Baja California South, is the terminal for the Gulf’s mining operations. A gypsum mine exists on nearby San Marcos Island. A French concession operated a copper mine nearby during the nineteenth century until it was taken over by the Mexican government and closed down in 1954.

Mulege, in Baja California South, looks very much like an oasis in the desert. It is surrounded by a virtual jungle of date palms and semi-tropical fruits planted originally by the Jesuit order in the early eighteenth century. The port contains several resort hotels catering to both Mexican and American tourists. Loreto, in Baja California South, is considered the oldest settlement in Baja California. The port also seeks to attract tourists to its resorts. As with Mulege, Loreto has an extensive growth of date palms surrounding it. The town has been destroyed several times in the past by earthquakes, severe chubascos, and fire. Loreto is the home of the Museum of the Missions of California.

La Paz is the state capital of Baja South. The port has excellent beaches, a fleet of fishing boats for hire, guides for hunting in the nearby hills, and government-sponsored duty-free stores for visitors. Regular ferry service crossing the Gulf itself exists between La Paz and Mazatlán, Sinaloa, on Mexico’s mainland. The first-class resort town of Cabo San Lucas is situated on the Gulf’s entrance to the Pacific. It contains the most luxurious hotels found in Baja, California. Campgrounds are also available for tourists traveling with their own accommodations. Game fishing is among the best available throughout the area. Ferry service is available between the port and Puerto Vallarta, Jalisco, on the Mexican mainland.

Puerto Peñasco and Puerto Kino, Sonora, have a modest tourist trade, including many visitors from Arizona. Entrepreneurs have built some small resort hotels near the ports and have laid out campgrounds for travelers with trailers. Sport fishing is the prime attraction at both locations. Guaymas, Sonora, is home to commercial anglers and acts as the staging area for commercial goods to be shipped inland as well. It has a natural harbor that is spacious and sheltered. Guaymas also exports local products such as cotton and grains from the hinterland. Good hotels and trailer parks are available at the seafront.

A shipping line operates some small freighters between Topolobampo in Sinaloa and La Paz. Shipping is restricted by the shifting sand bars at the bay entrance, where the port is situated, but fishing is excellent, and a wide variety of game fish can be found in the surrounding waters. Mazatlán, Sinaloa, is the key port for all of northwestern Mexico. The Mexican navy maintains a base at the port, and several small warships are in evidence. The largest sea traffic between Mexico and the Baja peninsula passes between Mazatlán and La Paz. An international airport services the area as well. Both hunting and sport fishing are available to the visitor. Good hotels, restaurants, and night clubs can be found in abundance.

Environmental Problems

The marine resources of the Gulf of California include some of the most outstanding varieties of fish and other sea creatures on the face of the globe. The Gulf is home to over nine hundred fish and marine animals. The question remains about how long this unusual concentration of marine riches will continue. Some species of fish have already disappeared from the Gulf’s waters. Others have reached such low numbers that they are seriously threatened with the same fate. Some already lost or in danger are cabrillas, black seabass, white seabass, Gulf groupers, yellowtails, manta rays, roosterfish, dog snappers, sierras, and vaquitas. The main problem lies with overfishing; fish are being taken illegally, often by bribing local law enforcement officials.

Commercial shrimp boats from Mexico’s mainland have raided the protected areas on the Gulf designed to ensure a continuation of the species. Authorities in Baja California have called for banning commercial fishing boats from the mainland, with commercial fishing permits restricted to Baja residents. Many feel that effective control of overfishing is better left in the hands of local authorities.

Other illegal activities have also hurt wildlife. In one instance, a cyanide-based dye used to mark drug drop-off spots killed both fish and mammals in the area. Government patrols have not been able to stop the smuggling. Gill net fishing, illegal in the Gulf, has also resulted in overkill. This indiscriminate method of harvesting lots of fish wholesale also scoops up many fingerlings and mature species. One Baja hotel owner stated that the nets had turned the seas around his property into a graveyard for marine life.

Corruption of government authorities is a significant problem. The fisheries on the mainland have millions of dollars at stake. Bribes have reached the highest level of government. The solution, in the eyes of most protectors of the environment, is to transfer the surveillance and law enforcement authority to the local level, where control will be in the hands of those who have the most to lose, the locals who make their living from fishing the Gulf. During the 1990s, the central government began creating civilian surveillance committees.

In 1996, Mexico’s president Ernesto Zedillo declared the bay at Loreto a national park, banning mainland shrimp trawlers from exploiting the area. As a result, marine life locally rebounded, and the local anglers were able to earn a living. The shrimp inside the park were multiplying, and the average size of the shrimp in the catch grew larger. Loreto became an example of environmental protection throughout the Gulf.

The conflict over environmental protection is not easily solved, but progress is being made. Mexican government officials and the Japanese firm Mitsubishi once clashed with environmentalists over a proposed saltworks to be built at the Laguna San Ignacio on the peninsula’s Pacific side. A group of dedicated scientists was convinced that implementing the plan would have a seriously adverse effect not only on the gray whale migrants who come there to calve but also on a number of other rare marine species making their homes in the area. The government’s experts denied that the program would have a negative environmental effect. Still, environmentalists won when public outcry caused Mitsubishi and the Mexican government to abandon their plans in 2000.

UNESCO World Heritage Site

Following the encouraging rebound of marine species in the Gulf of California following environmental protection efforts, further steps were taken to mark this biodiversity hot spot as a unique global treasure. The most important measure came in 2005 when the United Nations Educational, Scientific, and Cultural Organization (UNESCO) designated parts of the Gulf as a World Heritage site. Officially named the Islands and Protected Areas of the Gulf of California site, it comprises 244 different islets, islands, and coastlines in the region. It is intended to protect not only the rich marine life in the Gulf, but also the terrestrial life—seen as among the world's best examples of speciation—and natural features like cliffs and beaches.

Virtually every process studied by oceanographers can be observed in the Gulf of California, making it a unique asset to science. The protected area is believed to shelter as much as 39 percent of all the world's marine mammal species, including one-third of all types of cetaceans; 891 fish species, including ninety endemic varieties; and 695 types of vascular plants—the most of any World Heritage site. Despite conservationists' success in gaining official protection for the Gulf of California ecosystem, many species continued to decline due to threats from fishing, pollution, and habitat loss. In 2015, activists petitioned to have the World Heritage site listed as "in danger" due to the potential extinction of vaquita (a small porpoise) and totoaba fish, both of which are endemic to the Gulf of California. This "in danger" distinction was officially assigned in 2019.

In the mid-2020s, the Gulf of California remained one of the top areas in the world for biodiversity. To combat problems instigated by global climate change and human interaction with the Gulf, the Macrofauna Golfo Project was instituted in the twenty-first century. This project cataloged all marine life in the Gulf to better observe and protect its biodiversity. Pollution, tourism, illegal fishing, and the effects of global climate change continue to plague the Gulf of California. However, UNESCO, the Mexican government, and the International Union for Conservation of Nature continue to work together to protect it. 

Principal Terms

chubasco: a type of severe storm that occurs in the Gulf of California and along the west coast of Mexico from time to time

gill net: a large, meshed fishing net that allows the head of a fish to pass through, entangling its gill covers and preventing it from passing through or otherwise escaping; because of their size, gill nets often catch many marine animals in addition to the target fish

tectonics: the study of the processes that form the structural features of Earth’s crust

Bibliography

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