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Loreto Bay/Isla Espiritu Santo Migratory Flora and Fauna Reserve

Few marine areas in the world can compare with the biological importance and richness found in the Sea of Cortez (Gulf of California). Loreto Bay and Isla Espíritu Santo rank among the highest in the region in biological and ecological value. Evolutionary processes have shaped the unique ecology of the Sea of Cortez, especially that of offshore islands like Isla Espíritu Santo, which is home to a wealth of species found  nowhere else in the world.

did you know?

Pearl diving was once the chief economic activity on the Baja peninsula in the Gulf of California. The Pericue Indians had been collecting the gems for centuries when the Spaniards arrived.

Loreto Bay

Loreto Bay Marine Park © Will Heyman/TNC


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total area protected:
534,706 acres

Cortesian, Magdalena Transition, Mexican Temperate Pacific, Gulf of California Xeric Scrub, California Coastal Sage and Chaparral

partner organization:
Grupo Ecologista Antares(GEA), Niparaja, ISLA

Ecological Importance

With islands, wetlands, lagoons, mangroves, and beds of seagrass, the marine areas of Loreto Bay and Isla Espíritu Santo are home to abundant wildlife on both land and sea. Thirty-eight plant and animal species are found nowhere else but within these two reserves. The archipelago of Espíritu Santo harbors some 1,200 species, while the five-island chain of Loreto Bay is home to 29 marine mammal species—the most in all of Mexico. Fifteen species of whale, 17 species of marine birds, and five species of turtles frequent the area, including the endangered black sea turtle that feeds in the seagrass beds of Loreto Bay.


The location of Isla Espíritu Santo and Loreto Bay—at the entrance to the Sea of Cortez and a mere 25 kilometers from the mainland—creates a situation vulnerable to human impact. Domestic and foreign industrial fishing has taken a huge toll on both reserves. The common practice of dragging shrimp and fishing nets across the ocean floor alters these important ecosystems which support countless marine species. Uncontrolled harvesting of shrimp and fish also results in the capture of sea turtles, marine mammals, and spawning fish.

The sensitive areas of Loreto Bay and Isla Espíritu Santo have been altered by rapid coastal development and unchecked tourism. The influx of people to this historically sparsely populated area has resulted in the introduction of invasive species to the area. Native wildlife have been unable to adapt to the onslaught of goats, pigs, dogs, rats, mice, cats, rabbits, burros, and innumerable invasive insect and plant species that are now found in the region.

A Strategy of Success

Isla Espíritu Santo is one of the most visited areas within the Sea of Cortez. Before Parks in Peril (PiP), however, the reserve lacked a conservation plan and was increasingly threatened with development. Loreto Bay was equally threatened and faced pressures from development and invasive species, as well as uncontrolled fishing and other resource exploitation. When PiP began, the Mexican government had recently officially protected these areas, yet without the necessary financial resources for conservation. PiP was able to provide the areas with the funds to immediately implement resource management activities. PiP also provided adequate infrastructure and staff for the preserves, which had been previously absent. Both parks are now able to fund conservation activities by collecting park entrance and camping fees.

Fundamental conservation activities such as patrolling, monitoring, tourism management, and environmental education were established in both reserves. In Isla Espíritu Santo, the number of tourists and researchers that work in the area without permission has been reduced. In Loreto Bay, basic technologies such as radio communications, GIS, and computers as well as vehicles and boats were provided.

In Isla Espíritu Santo, a Community Development Program has been established to promote pilot sustainable resource use projects and an environmental education program is being incorporated into the formal education system’s textbooks.

In Loreto Bay, monitoring projects led to the closing of two public beaches and within five years, tourism impacts were reduced by 90 percent at all of the beaches. An environmental educator was also hired to visit local schools and had reached almost 2,000 students by the end of PiP funding.

PiP began strengthening the newly-formed partner organizations of Grupo Ecologista Antares (GEA) in Loreto Bay, and Niparaja and ISLA in Isla Espíritu Santo, all of which were capable of long-term management upon site consolidation. Both reserves have become models for conservation endeavors throughout the Sea of Cortez.

Read more about the Sea of Cortez (Gulf of California)...

Conservación del Territorio Insular Mexicano (ISLA)
The Nature Conservancy in the Gulf of California
Online Field Guide to the Gulf of California

Read more about projects in Mexico...

El Pinacate/Gran Desierto del Altar Biosphere Reserve
Cuatro Ciénegas National Wildlife Reserve

Calakmul Biosphere Reserve
Ría Celestún & Ría Lagartos Biosphere Reserves
Ajos Bavispe Biosphere Reserve
El Triunfo Biosphere Reserve
Sian Ka'an Biosphere Reserve
El Ocote Biosphere Reserve

La Encrucijada Biosphere Reserve

Mexico Partner Organizations

The Nature Conservancy in Mexico