Pencil Urchin

Found in the lower intertidal zone, these beautiful echinoderms are heavily defended with spines and toxins. A touch to these thick, blunt spines will give a painful wound. The pencil urchin grazes on algae, grasses, kelp, sponges and decaying fish matter. It scrapes food into its mouth using five beak-like teeth. The urchins traverse the ocean floor on hundreds of tiny tube-like feet.


So called because their gills (branchs) are exposed on their backs, nudibranchs are among the most colorful and unique creatures in the tidepools.  Nudibranchs are gastropods, meaning stomach-foot.  They use the same organ for both feeding and locomotion.  Snails are also gastropods; you can think of nudibranchs as snails without shells.

Isla San Jorge: Ecology

Consisting of three main islands and four smaller islands, Isla San Jorge is arid and rocky with no known native plants. It sounds inhospitable, but fish-eating bats, blue-footed boobies, magnificent tropicbirds, and California sea lions thrive on the Islands. The reefs and waters around San Jorge support a diversity of life. Marine invertebrates of commercial importance, like sea cucumbers, scallops, mussels, oysters, snails and octopi as well as a variety of fish live in the waters surrounding San Jorge.


Most echinoderms, (think starfish, urchins and sea cucumbers) are symmetrical along five different axes, usually with five arms. Not sunstars, they have more than 20 arms that pry open mussels, clams and scallops. The sunstar at Rocky Point was once famed among marine biologists for its keystone role as top predator of the rocky intertidal. By eating a variety of prey, it helped keep numbers down and thus maintained the diversity of the rocky habitat. As it turns out there are other predators that play the same role, making the sunstar one of several key predators. Susceptible to high temperatures the sunstar disappeared from the Gulf’s tidepools in the early 1990s. All echinoderms are susceptible to temperature increases and may be among the first to suffer from global warming.

What’s in a Name?

The name Puerto Peñasco derives from 19th century maps drafted by Lieutenant William Hardy who visited the region to scout for potential pearl fisheries. Lt. Hardy dubbed the area as Rocky Point, after the prominent rocky basaltic headland that locates the town today.  It later became known in Spanish as Puerto Peñasco or “Rocky Port”, as the estuary at the base of the mountain gave natural refuge to boats. The Puerto Peñasco estuary was converted into the current harbor in 1967. Rocky Point was also known by fishermen as “Cerro Ballena” or Whale Hill, for its whale-like shape.


There are thirty-four species of cetaceans (whales, dolphins and porpoises) found in the Gulf of California. Eight species of baleen whales have been seen in the Gulf. The fin whale is here year round, while humpbacks feed in the rich waters of the Gulf after bearing young. The sperm whale is found year-round in the deeper waters of the Gulf. Gray whales, known for their winter migration to the Pacific lagoons of Baja California for calving can also be found venturing into the Gulf with their young.

Barrel Cactus (Biznaga)

This round and ribbed cactus is aptly named. It grows throughout the Sonoran Desert. Many cacti have strategies to prevent sunburn. Saguaros develop a tougher skin on their exposed side. Barrel cacti tend to lean toward the south to protect more of their surface from the sun. This is why they are sometimes called the “compass cactus.”

Sport Fishing

Sport or recreational fishing involves many types of boats and species, and both local and foreign fishermen. Sport fishers target top predator fish, like bass and grouper, which has a cascading effect on the marine ecosystem. As tourism booms sport fishing has grown in importance. Today there are about 170 sport fishing boats based in Puerto Peñasco.  Industrial and small-scale fisheries still dominate in the gulf.

The Sea of Cortez or The Gulf of California?

We know the body of water that lies between Baja California and Sonora by both names. Which to use? The Sea of Cortez, named for the early Spanish explorer, Hernan Cortez, was once used more in Spanish. Today it has become the more quaint and romantic name for the sea. Scientists tend to call it the Gulf of California.

The Vaquita

Also called the Gulf of California porpoise, this is an endemic species, only found in the northern part of the Gulf of California.  Like all porpoises it has a blunt snout and spade-like teeth, and produces one calf every other year. Today the vaquita is considered the most endangered marine mammal on Earth, with probably fewer than 250 individuals left. The primary threat to this species is the use of gillnets by coastal fishermen of the region. The species’ survival depends on finding alternatives livelihoods for fishermen that depend on these fisheries or finding alternative gear for the most economically important fisheries, such as shrimp.


All whales, dolphins and porpoises are cetaceans, a group of marine mammals highly adapted to aquatic life. Baleen whales are belong to the group mysticeti (“mustached sea creature”), while toothed whales, dolphins and porpoises are odonticetis (“toothed sea creature”). Did you know that the Gulf of California is home to 39% of the world’s marine mammals and a third of the world’s cetaceans.

Community Education

“CEDO’s environmental program with Peñacso’s fifth graders has been a tremendous success. The children learn about the local ecosystems in fun and dynamic ways, and CEDO’s staff is extremely well-prepared and manages the groups well. Kids don’t have many opportunities to take field trips, or to learn about our natural resources, so we appreciate what CEDO has been able to do.”
– Profesor Jorge Carrasco, Escuela Primaria Artículo 115 Constitucional, Puerto Peñasco


A hydroid looks like a feathery plant, but it is actually a colony of animals! Its eggs rest on the branches of the ‘feathers’, which when released will grow into jellyfish. In this unique system of ‘alternating generations’ the jellyfish will then lay eggs which attach to the sea floor and grow into hydroids. One species of hydroid at Puerto Peñasco release stinging nematocysts into the water, when stimulated by changes in water pressure. Swimmers may encounter the mild stinging sensation it causes.

Tidepool Shrimp

These appropriately named organisms are found in the tidepools. They are small bodied arthropods that scavenge the intertidal. They use their insect-like eyes to search for dead animal parts. Long antennae and setae (tiny hairs on the legs and arms of the shrimp) help it to ‘see’ its environment through the sense of touch and by sensing chemicals. Using their back parts (called swimmerets) as paddles shrimp can swim and maneuver through the tidepools. Can you spot a shrimp in the tidepools? It may be difficult because its body is transparent allowing it to pass almost invisibly through the pools.

On the Gulf

“It is one of the world’s remaining wildernesses with most islands and marine areas in pristine conditions. The islands provide a dramatic setting due to their rugged forms with high cliffs and sandy beaches surrounded by turquoise waters. The diversity and abundance of marine life associated with spectacular submarine forms and high water transparency makes the region a diver’s paradise. The site is considered and “ocean oasis” and the “world’s aquarium” for its diversity and abundance of marine life, with 891 species of fishes, 34 cetaceans, 5 species of marine turtles and 25 species of corals. It is also important worldwide for its marine endemism, with 90 species of endemic fish. It includes 181species of birds with 90% of the world’s population of Heermann’s Gulls.”
– UNESCO World Heritage Site Declaration


This critically endangered fish faces both habitat loss and mortality in fishermen’s nets. Totoabas depend on the brackish water in the delta of the Colorado River to reproduce. Populations have suffered since the river’s flow has been reduced to 4% of its former level due to water use in the western United States and northern Mexico. The totoaba fishery, which reached its peaked in the middle of the last century, decimated populations during their spawning.  Shrimp trawling operations also captured an estimated 90% of the juveniles of this species as bycatch. With all these strikes against it, by the early 1970’s the totoaba became the first marine fish to be considered endangered. Totoabas can grow up to 2 meters (6.5 feet) in length and weigh up to 100 kilograms (220 pounds).

Swimming File Clam

Unlike other clams, which attach to the seafloor with byssal threads, the swimming file clam moves around the tidepools by pumping the two halves of its shell. Its orange tentacles enable it to filter food particles from the water. These delicate clams are small, not growing longer than 3-4 centimeters. If you tidepool at dusk, moving algae out the way, you’re likely to see this gem of the rocky reef.

A Fishing Village: Tourist Destination

American vacationers began trickling into Puerto Peñasco in the 1960s and 70s to build their second homes and retirement communities on the outskirts of town. There were few amenities: no running water, electricity, air conditioning or telephone in those days. But beautiful beaches and abundant fisheries were hard to resist, so the growing desert populations of Phoenix and Tucson flocked to the area. By the mid-90’s the first mega-development, Plaza Las Glorias, came to Peñasco. After 9-11 the area boomed with tourist developments. The price of real estate skyrocketed and the condo and time share markets arrived. These changes have energized Peñasco, but have come at a social and environmental cost.

Oyster Farms

In the 1970’s several families in Peñasco looked to growing oysters as an economic opportunity. Today there are seven oyster farms located in the protected waters of local estuaries. These family operations employ rows of stacked trays, anchored in coastal mudflats, to grow oysters from larva to adults. Some families market oysters in town, while most sell them under palapas in the wetlands where they work. Oysterfarming requires frequent cleaning and sorting of the oysters as they develop in the trays. This form of aquaculture has little negative impact on the ecosystem, and could continue indefinitely without exhausting resources, making it a truly sustainable enterprise.

Blue Crab

Found in the estuaries and along the coasts of the gulf, blue crabs are highly adapted predators. Rather than a fourth set of legs, these crabs are equipped with fins for fast swimming in strong currents. CEDO recently confirmed the presence of two closely related species in the region, one with more pronounced facial spines.


“By promoting environmental awareness, disseminating knowledge, and encouraging civic participation, CEDO is a fundamental force driving social openness, civic dialogue, and honest and transparent decision-making. Although essentially directed towards the environment, CEDO has been above all the promoter of a vision of social progress that I embrace completely: the vision of an open and participatory society consciously building its own future. I recommend the nomination of CEDO for the National Conservation Award, in the most enthusiastic and emphatic manner. For its brilliant trajectory, CEDO clearly deserves this recognition.”
– Dr. Exequiel Ezcurra
Biodiversity Research Center of the Californias, San Diego Natural History Museum

Las Conchas

CEDO found its home on this long stretch of beach south of Puerto Peñasco, in 1980. In the early days, sea lions would haul out in Las Conchas, and today they can be still be seen on shore at the Cholla bay headline. In the background you can see the extinct volcano for which Rocky Point is named.


You’ll find the words ‘estuary’, ‘estero’ and ‘wetland’ throughout our site. A wetland is any fresh or salt water habitat which is inundated with water at least once year. An estuary is a coastal wetland where salt and fresh water mix. Scientifically speaking, all of the wetlands we work with in the northern Gulf are ‘negative estuaries’ or ‘hypersaline lagoons’ because they receive no freshwater influx.  Negative estuaries are called ‘esteros’ in Spanish, so that’s how we often refer to them.

Fisherman Testimonial

My name is Cuco Salazar, I’m a commercial diver on Peñasco’s rocky reefs. When I heard that CEDO had won the 2007 National Conservation Award it reminded me of when I was interviewed on the radio about the protests in Peñasco in response to the enforcement of fisheries regulation in the Biosphere Reserve. While I shared my story, many people called in to say “the sea belongs to those who work it” – I said, you know, it’s different – farmers sow their seeds and care for their crops, we don’t sow the sea and we keep taking from it, fishing all year long. These issues are complex, but that’s what makes this recognition of CEDO all the more important.

Least Tern Habitat

Least terns, endangered in Mexico, have very particular nesting habits. They chose flat, sparsely vegetated sand bars, spits and beaches, with little human disturbance. Leaving shells on these beaches is a good idea, especially the big white ones, because terns depend on these to camouflage their eggs. This protects them from aerial predators. Terns still have to face threats from ground predators, like coyotes and dogs – they are also impacted by people entering their colonies on ATVs. When parents leave their nests to defend the colony for just a few moments, their eggs are vulnerable to the baking sun. You’ll see this bird along the coasts of Peñasco from April to August, after raising their young they migrate to South America.

California Sea Lions

“I saw a seal!” Well, in the Gulf of California, you probably saw a sea lion. We don’t have seals in the Northern Gulf of California. While both are pinnipeds, sea lions are much bigger and better equipped for spending time on the land (they have external ears and hind legs for maneuver on land). Sea lions depend upon isolated rocky shores where they can haul out to rest and reproduce. The islands of the Gulf are perfect habitat, critical for this species survival.. Male sea lions fiercely defend their stretch of beach against all rivals, maintaining a safe place for their mates to raise young.

Fishing Down the Food Web

In the Gulf of California coastal fishermen face an uncertain future. Their catch varies unpredictably, and they often find themselves fishing down the food web, each year taking less, smaller and lower quality fish. Here in Kino Bay, women pack jellyfish for sale in Asia. In this community, the largest catch was not grouper or bass, instead they netted jellies – a creature formally not worth harvesting. In the Gulf of California large predatory fish, like the gulf grouper, totoaba and several species of shark were once abundant. Due to these fishing patterns, each of these predatory species was reduced in number and are now uncommon. A reduction in the population of top predators means large shifts in prey populations, and can disrupt entire food webs.

Endemic Species

Plants or animals with limited ranges are said to be endemic. In the Northern Gulf of California we have an endemic porpoise, the vaquita, which is not found in any other sea. Due to its geographic isolation, the Gulf of California is home to many endemics, including 90 species of fish. Endemic species are much more vulnerable to population declines and extinctions than species with large geographic ranges.

Halophyte Plants

Literally salt-loving, these plants have adapted to survive the high salinities in the hypersaline estuaries of the Northern Gulf. Rather than excluding salt at their roots, halophytes will take in the salts and then find ways to deal with this potentially toxic substance. Some species excrete the salts, others isolate them into vacuoles.  While mangroves thrive in wetlands below 29º N latitude, the northern wetlands are dominated by several species of salt tolerant shrubs, succulents and grasses, including salt grass, pickleweed and saltwort. Halophytes were harvested by indigenous groups. Nypa, Distichlis palmeri, was used by the Cucapa of the Colorado River delta. Today halophytes are cultivated using seawater for a variety of uses.


The benthos is the floor of a sea or lake. Many organisms are specialists in benthic environments, living on, in or attached to the bottom. Here, in the Gulf of California, we have sandy, muddy and rocky bottoms, each with its unique assemblage of species.  The least common, and most diverse of these three habitats are rocky reefs. These reefs are formed either of basalt, a volcanic rock, or coquina, a sedimentary rock formed form decomposing materials, shells, rocks and sand. Rocky reefs give algae, tunicates, sponges a firm place to attach.

Geoduck Fishery

These large and strange clams can live for 100 years, filter-feeding through their siphon in sandy bottoms in the Northern Gulf of California. Pronounced “Gooeyduck”, the fishery for geoduck clams is just beginning in our region. CEDO supports one cooperative interested in developing this  fishery as a sustainable enterprise (socio-economically as well as ecologically) from the beginning. The clam also has potential for aquaculture, as it is currently grown with commercial success in the Pacific Northwest of the United States.

A Safety Net for Fisheries

Both in Mexico and globally the Northern Gulf of California is a priority for marine conservation. To protect the spawning grounds of many commercial species and habitat of endangered, endemic animals such as the totoaba and the vaquita, in 1993 the northern most part of the Gulf was designated as the upper Gulf of California/Colorado River Delta Biosphere Reserve. As one of Mexico’s first marine reserves, it has served as an important laboratory for learning about the conservation of marine resources and for fisheries management.

Black Murex

These fist-sized predatory snails have been harvested by local commercial divers since the early 1990s. The snail’s habit of forming massive spawning aggregations makes it vulnerable and an easy catch. With the divers harvest increasing through the 1990s, the population began to show serious signs of decline. Concerned, the divers approached CEDO to try to better manage this and other benthic mollusks (snails, clams and relatives that live on the ocean bottom).

Ecosystem Based Management (EBM)

Can you imagine a physician making a health diagnosis based on a patient’s blood pressure alone? How about a patient’s body temperature? Suppose that the prescription is made without taking into consideration possible side effects. Surely such a diagnosis has a low chance of being accurate, and, even if the prescription works, it will likely be by chance. The reason for this is that the human body is a complex system and a rise in blood pressure or temperature can be due to an illness in one or many of its components; therefore, a diagnosis should be made based on the measurement of several health indicators and medicine prescribed with consideration of possible side effects.

The complexity of processes in a human body is analogous to those of ecosystems. Though marine ecosystems are complex systems, the field of fisheries science and management has traditionally made diagnoses and recommendations based only on the maximum sustainable catch of a single target species, often ignoring habitat, predators, and prey of the targeted species, not to mention other ecosystem components and interactions. In contrast, the Ecosystem Based Management (EBM) that PANGAS supports is an integrated approach that considers the complexities of ecosystem dynamics, the social and economic needs of human communities, and the long-term maintenance of diverse, functioning and healthy ecosystems.

Small Scale Fishing (Artisanal Fishers)

In terms of the number of people involved, small-scale fishing, artisanal or coastal fishing, is the most important of the three types of fisheries in this region, and throughout the world. Small-scale fisheries are characterized by their low level of investment in equipment as compared to industrial activities and for their dynamic nature. Outboard motors and small fiber glass boats called pangas are used to fish a variety of species in shallow coastal waters employing several different types of gear. In 2005 there were an estimated 1,000 pangas in the upper Gulf.

Industrial Fishing

One of the three kinds of fisheries in the Gulf, industrial fishing is characterized by a large investment in equipment and infrastructure and well developed commercialization of products. In the past most government management efforts have focused on these fisheries.  The most important industrial fishery in the upper Gulf is shrimp trawling. In 2002 the upper Gulf fleet, mostly located at Puerto Peñasco consisted of about 120 boats These large boats drag nets across the ocean floor and the target, shrimp, is channeled into a large purse. Unfortunately many other species are also funneled into these nets as bycatch. In recent years shrimp trawlers have been required to use fish and turtle excluder devices to minimize bycatch. Sardine fisheries are also an important industrial fishery of the Northern Gulf, especially near the midriff islands.

The Tourism Alternative

In 2007, four fishermen traded their fishing boats for skiffs equipped for tourism. Today tourists, from birdwatchers to sports-fishermen, can explore Peñasco’s shores with knowledgeable and experienced fishermen. CEDO continues to support this transition from fishing to tourism in the upper Gulf, where the pressure on endangered species like the vaquita is high.

Blue Crab Trap Fishery

Crab traps are baited wire cages, which rest on the seafloor. A buoy, often an empty soda bottle, tethered to the trap helps the fishermen find it.  The trap’s funneled sides make it easy for crabs to enter but hard for them to leave.  During the peak season crab fishermen, like lobstermen, run their lines of traps inshore, on the coasts and estuaries near Peñasco. At Bahia San Jorge, 50 kilometers south of Peñasco, a fisheries cooperative determines the capture rate for its crab fishery.  In this community, pick up trucks ferry fishermen, boats and traps back and forth along 12 kilometers of beach. At the end of the harvest they are weighted down with packed crates of crab. The crabs are later shipped and canned elsewhere, bringing little return to the community.

A Fishing Village: Origins

Puerto Peñasco, like other coastal towns of the upper Gulf, was first settled by fishermen who followed the totoaba, a giant corvina, as it migrated north to the Colorado River Delta to spawn.  In 1927 a freshwater well was dug near the old port allowing the seasonal fishing camp to evolve into a permanent Mexican settlement. The abundance of fish also lured American sport fishing enthusiasts to Rocky Point, which became popular with the Hollywood crowd as well, especially during the U.S. Prohibition era. Fishermen were reluctant to bring their families until this rowdy crowd was forced to leave by presidential order.

Enriching the Debate

By taking a close look at development projects before they are approved, CEDO has been slowly changing the dialogue about development at Puerto Peñasco. The Environmental Impact Statement submitted by Sandy Beach Resorts for the double headed marina, opening at Sandy Beach and at Cholla Bay, did not withstand CEDO’s careful scrutiny which outlined the many environmental and social impacts the project would cause. Authorities asked developers to withdraw their project. It was resubmitted without the Cholla Bay end of the marina. This too was scrutinized by CEDO and other fishers whose fishing grounds would be destroyed by construction of a marina and altering currents in the region. The legal dialogue continues with this development which is now managing the projects and permit requests for each side of the marina separately. CEDO’s goal is to force developers to be responsible for the environmental impacts caused by their projects, by addressing them adequately and looking for alternatives. Destruction of fishing grounds, habitat for endangered species and other key ecological processes should not be taken lightly.

Long-Billed Curlew

The logo for the Peñasco Estero Conservation Fund shows the silhouette of a Long-billed Curlew, a large shorebird, common in our wetlands throughout the year. This species is considered near-threatened by the Mexican endangered species act, and is a species of special concern in the United States, due to range-wide declines. If you visit one of northern Sonora’s wetlands, you’ll be sure to see these graceful birds dotting the mudflats, probing their long, down-curved bills into the burrows of shrimp and crabs. Although we see them throughout the year, most of the population flies north to the Great Plains of the United States to breed in late spring, early summer.

Early Fisheries: Totoaba & Shark

At the end of World War II, the U.S. government assisted the Mexican government to pave Highway 8 from Lukeville, Arizona south to Puerto Peñasco, Sonora. International markets opened. Boat building became an important industry because of easy access to materials in the U.S.  War time research identified shark liver oil as an important source of Vitamin A.  By the 1950’s shark fishing and industrial shrimp fisheries were booming, making Puerto Peñasco one of Mexico’s most productive ports. Fishing was so successful in these spawning grounds that whole populations were decimated. The totoaba became the first marine fish to be listed as endangered and it received full protection in Mexico in 1975. Shark species were decimated here and throughout the world.


Echinoderms, a group including sea stars, sea cucumbers and urchins, are the most diverse and populous marine species. They play key roles in deep and shallow seas – eating algae, breaking down rocks, aerating the seafloor, and as generalist predators. In the tidepools near Rocky Point, the most common echinoderms you’ll find are sunstars, brittle stars, pencil and purple urchins.

School Groups at CEDO

“CEDO is a great place for class trips – not just for the diversity of life in the nearby tidepools – but also for the community experience it creates for students. When students cook together, work together, enjoy a bonfire and then sleep out under the stars there are lots of opportunities for positive interactions. CEDO also provides an opportunity for students to see conservation and research in action, by interacting with visiting researchers and CEDO staff. It is a very special and beautiful place – it’s not everywhere you can count on seeing eight phyla of intertidal invertebrates, catch beautiful sunsets and regularly see dolphins!”
– Dr. Katrina Mangin
Marine Ecology Professor, Ecology and Evolutionary Biology, University of Arizona

CEDO & Small Business

Because we believe that small businesses and local ownership are key to social and environmental well-being, we support local ecotourism initiatives near Peñasco. At oysterfarms in Estero Morúa CEDO has promoted the ‘El Barco’ restaurant, with an education mural, as well as ‘Kayaks Noemi’ a kayak rental initiative. NaturArte, is a broader project, aimed at developing and connecting ecotourism efforts along a wetland corridor.


Since its inception in 2000, CEDO’s field education internship has provided interns with “direct experience of the ‘heart and spirit’ of CEDO’s mission” as well as practical experience in outdoor education. Interns also benefit from interactions with CEDO staff, and visiting students and researchers. One former intern raves about the “opportunity to immerse myself in the absolutely gorgeous landscape of the Sea of Cortez.”


Ospreys are superb fishers and indeed eat little else. That’s why you find these birds near ponds, rivers, lakes, and coastlines around the world. Ospreys dive to the water’s surface from some 30 to 100 feet (9 to 30 meters) up. They have gripping pads on their feet to help them pluck fish from the water and carry them for great distances. In flight, ospreys will orient the fish headfirst to ease wind resistance. North American osprey populations became endangered in the 1950s due to chemical pollutants such as DDT. Ospreys have rebounded significantly in recent decades due to less DDT usage.  Ospreys nest where they have a panoramic view. The birds happily build large stick-and-sod nests on telephone poles, channel markers and treetops. CEDO’s osprey station has been occupied nearly every year since it was erected.

Shell Middens

An observant visitor to Puerto Peñasco’s environs will notice piles of shells, accumulated over thousands of years of indigenous pilgrimages to the region. The Tohono O’odham tradition was a three day walk across the driest part of the Sonoran desert to collect salt and shells from the coast. Pilgrims would consume clams, leaving the shells in the piles we see today.These pilgrimages ended in the 1950s, coinciding with the beginning of vacationers from the United States. To distinguish recent from ancient clam shells, look for a honey-combed surface where the shell is broken.

Students at CEDO

” CEDO has always been extremely welcoming and helpful to the University of Arizona’s Marine Awareness and Conservation Society (MACS). CEDO’s staff has made it possible for us to participate in International Beach Cleanups, provided a wonderful place for us to stay, and given educational presentations at our club’s meetings. Our experiences at CEDO have increased our members’ awe and wonder about the marine environment, allowing them to further our outreach and promote conservation throughout the Tucson area. The time I spent at CEDO stands out to me as one of the highlights of my college career.”
– Moriah Flagler, Fine Arts, University of Arizona

UNESCO World Heritage Sites

UNESCO (The United Nations Educational, Scientific and Cultural Organization) defines World Heritage Sites as places of unique cultural or natural importance which belong to all the peoples of the world, regardless of where they are located. A World Heritage Site designation brings attention to a place, and provides an impetus for its protection. The islands and protected areas of the Gulf of California were declared a World Heritage Site in 2005, owing to their diversity and ‘striking natural beauty.’

Upper Gulf or Northern Gulf

Biologists studying the distribution of animals in the Pacific Ocean, saw three distinct regions in the Gulf of California: the Nothern, Central and Southern Gulf.  The Northern Gulf is considered to be the area north of San Francisquito, Baja California and Bahia Kino, Sonora. In 1993, the northern-most part of this region, from San Felipe and Puerto Peñasco northwards, was designated as the upper Gulf of California and Colorado River Delta Biosphere Reserve. Oceanographically this area is distinct, as it is under the influence of the Colorado River. It is known as a region of great importance for commercial fisheries and as a spawning ground. The upper Gulf is used casually to refer to the northernmost region of the Northern Gulf.