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RSW Living Magazine


Mar 08, 2023 08:00AM ● By Glenn Ostle

A pair of California sea lions play among the huge schools of fish around the islets. Photo by Glenn Ostle

Located between the Mexican mainland to the east and the mountainous peninsula of Baja California to the west, the narrow Sea of Cortez is one of the most biologically diverse bodies of water on the planet. Home to more than 900 species of fish, thousands of species of invertebrates, and a wide array of marine life, it so impressed famed oceanographer Jacques Cousteau that he referred to it as the “aquarium of the world.”
My partner, Pam, and I have been scuba diving in Mexico a number of times, but it had been almost 25 years since we were last in La Paz, the capital of the Mexican state of Baja California Sur. We were eagerly looking forward to renewing our acquaintance with the underwater wonders of this area when we returned there with a dive group in late 2022.
One site we were especially anxious to revisit was Los Islotes, a pair of rocky islets at the northernmost point of the land portion of the Espiritu Santo National Park. Only a short daytrip from La Paz, this is home to the largest reproductive colony of California sea lions in the Sea of Cortez. With a population of 400-500 animals, Los Islotes is a popular site for both diving and snorkeling.
On our way to the islands, the Sea of Cortez lived up to its reputation for stunning sea life. A pod of bottlenose dolphins escorted our boat part way, leaping and twisting in the air with seemingly joyful abandon. A misty spray in the distance turned out to be a juvenile humpback whale that came close to our boat and breached several times to the delight of everyone on board. We even witnessed a number of mobula rays jumping out of the water and flapping their stubby wings.
As we approached Los Islotes, the peaks of the islets appeared striped with white guano from the many pelicans and frigatebirds that continuously circle overhead. The birds seem to take turns diving straight down into the water to capture mouthfuls of fish from the mind-blowing schools that gather just below the waves. The islets are also home to brown-and blue-footed boobies, and while diving we even witnessed the surreal sight of cormorant birds zipping past us underwater, in search of a meal.

Sea lions can sleep up to 12 hours at a time, and they love to lie all over and nuzzle each other. Photo by Glenn Ostle


On the rocks, sea lions bark and squabble with one another, and large, melon-headed bulls spend their days posturing for females or patrolling the underwater area, warning snorkelers and divers not to get too close.
One of the islets features a natural arch where sun rays shine down to highlight tall walls covered in bright cup corals.
Twenty-five years ago, ours was the only boat around. This time there were more than 20 other
boats floating just offshore, each busy unloading dozens of snorkelers and divers who quickly began kicking excitedly toward the islands.
The water is quite shallow close to the rocks, with depths from 10-50 feet. Diving is the best way to avoid the crowds of life-jacketed snorkelers, but in shallow areas this often puts you within range of the their kicking feet.
Sharing the water with aggressive sea lions can be a little unnerving at first, but it doesn’t take long to realize that the animals want to play with you as much as you want to interact with them. They will zoom around you, chew on your fins, try to bite your hair, and in short, make lovable pests of themselves.
Juvenile sea lions, with their puppy-like faces, have lots of personality. Some are shy, while others
delight in dive bombing you or swimming up close without warning, to look you in the eye.
The water seems to boil with life, and it is hypnotic to watch the sea lions dart into huge aggregations of silver fish, only to burst back through the schools, splitting and dividing them. The fish quickly regroup but often so densely that it can be difficult even to see another diver just a few feet away.
Watching this underwater ballet is mesmerizing. Rather than feeling intimidated, it is easy to get
into the swing of the action as you realize you have become part of it.
The California sea lions in and around La Paz are a great attraction for locals and visitors alike and a financial boon for the city. But all the attention can take its toll on the animals themselves. Sea lions have been protected under Mexican law since 1994, but the laws are no match for problems caused by humans.
Los Islotes is a no-take zone that is enforced by La Comisión Nacional de Áreas Naturales Protegidas (CONANP), which directs the management of natural protected areas in Mexico. But as the islands are quite remote, illegal fishing still takes place, which can leave behind “ghost” fishing gear in which sea lions can become entangled and die or sustain serious injuries.
Patrol boats regularly survey the park, checking the permits and compliance of tour boats and looking for illegal fishing activity. In addition, a Mexican-registered organization called Rescate de Lobos Marinos (Sea Lion Rescue Project) regularly visits the islands to provide rescue and veterinary care (
Sea lions populate Los Islotes throughout the year, but a good time to visit is between October and March, as this is also the best season to see whales in the Sea of Cortez. Just be sure to bundle up as the water at Los Islotes can be quite cool, with average temperatures in the mid-70 degrees Fahrenheit.
Swimming with sea lions at this special place is safe, enjoyable, and a singular experience that you won’t soon forget.
Glenn Ostle is a freelance writer and photographer living in Charlotte, North Carolina. He has been writing and providing photos for TOTI magazines for more than 20 years. To see more of his work, go to: or ostleglenn on Instagram.