From the Field

Sea of Cortez: Conserving the World’s Aquarium

March 24, 2014

Snorkeling with sea lions. Photo: © Mark Godfrey/TNC

Imagine an impossibly beautiful place where the Sonoran Desert meets a clear blue ocean that is teeming with life – colonies of playful and mischievous sea lions, flying mobulas (manta rays that leap out of the water) and endemic species of reef fishes (that only occur in that part of the world), large colonies of seabirds nesting and soaring overhead, humpback whales breaching, and blue whales and large schools of dolphins cruising past.

That is the Gulf of California, also known as the Sea of Cortez, and it is one of the most rich and spectacular marine environments on earth — so much so that it inspired Jacques Cousteau to call it the “Aquarium of the World.”

Recently I had the great privilege of visiting this amazing place, and snorkeling with many of its famous inhabitants.

One day we cruised out to Isla Espiritu Santo, a biosphere reserve, to see what awaited us out there.

Flying mobula. Photo: Alison Green
Flying mobula. Photo: Alison Green

On the way out to the island we were surrounded by large groups of flying mobulas, which were leaping out of the water all around us.

They are a small species of manta ray that jump more than other mantas do. Scientists are not sure why they do that – it is just one of many mysteries in the Sea of Cortez. (This video shows the spectacle well).


Perhaps they do it to escape a potential predator, or as part of a courtship ritual, or to rid themselves of skin parasites?

At one point we actually managed to jump in the water with a group of about 50 or so of them, and we could see them swirling around each other and racing towards the surface. So it was easy to see how they could just keep going and leap out of the water.

Where the Sonoran Desert meets the ocean: the Sea of Cortez. Photo: © WIll Heyman/TNC

We also snorkeled with the playful (and sometimes a little-bit-scary) California sea lions at Los Islotes – a group of small islands off Isla Espiritu Santo.

The sea lions darted around us in small circles and sometimes raced up to us at great speed – screeching to a halt just inches away from us. Although occasionally one of the males got a bit territorial and menacing – like the one who chased us out of the water and back into the boat.

It was a bit scary, but that just added to the excitement of being there.

But by far the best part was when I saw a playful young sea lion sneak up behind Diana Bermudez, who leads our Baja Marine Initiative, and bite her on the bum!  I laughed so hard I almost drowned.

Ensuring a Future for the Sea of Cortez

Commercial fishing is a major driver of the local economy. Photo: © Mark Godfrey/TNC
Commercial fishing is a major driver of the local economy. Photo: © Mark Godfrey/TNC

But it’s not all fun and games. The Gulf of California is not only a beautiful place, but the outstanding marine environment provides significant ecosystem services to the people.

This region supplies 70% of Mexico’s fisheries, and is an important area for both commercial and sport fishing.  It is also a major destination for tourism.

While fishing and tourism are the major economic drivers in the Gulf, and they provide important income and livelihoods for local people, they also provide the greatest challenges for conservation and management in terms of overharvesting of marine resources and unsustainable coastal development.

In 2012, the Conservancy and partners launched the Baja Marine Initiative to transform ocean management and help bring 10 million hectares of the Gulf of California and the adjacent Northern Mexico Pacific under protection or effective fisheries management.

In the past, the Conservancy’s focus has been supporting the establishment and effective management of federal protected areas as a primary tool for biodiversity conservation in this region.

However, to date only 7% of the region is protected and less than 0.5% is a no-take area, so there is a lot more work to do.

The Conservancy is now scaling up our work in the region to address the full range of challenges and opportunities by broadening our approach to work with other sectors (particularly fisheries and tourism) to develop an integrated planning and management framework for the region where conservation, food security and economic development goals can be achieved simultaneously for the benefit of people and nature.

Join the Discussion

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  1. So nice to see all the good work i am always inspired to see what you are doing.
    All my Best Wishes

    1. Thank you Michael.
      It was your Dad Stan Harris who inspired me to work in conservation in the first place.

  2. I visited the Sea of Cortez long time ago and your blog makes me want to go back! would love to see the nobulas. Great to hear of your work there. best, gaby

  3. It’s a beautiful & charming place. All the sights are too wondering. Video of large groups of flying mobulas under the sea and all the post are so good. Thanks for this kind of Blog.

  4. While I find the footage of the rays incredibly beautiful the Sea of Cortez eco system has been and continues to be in decline for 40 years. I have swam underwater off Espirtu Santo gliding over hundreds of carved up carcasses of these creatures. Over the past 25 years I have travelled the Baja coastline extensively and the reality is that the conservation areas are completely ignored with zero enforcement.

  5. I live on the Sea of Cortez in the northern region of Baja. The wildlife( both on land and off) is pretty spectacular here and rather amazing at times. I would love to know the most likely areas to see this breaching behavior of the Mobulas. I would like to see this in person.

  6. I currently live near Tucson AZ and have gone on several kayaking trips in the Sea of Cortez in the last two years and have noticed the problems with sea lions entangled in fishing nets (gill nets) where they are strangling and dying a slow painful death as a result. Is there anything being done to help the sea lions? I would like to help in any way I can. I have had experience working at seal rescue centers and have extensive experience with boating, snorkeling and some diving. Please contact me and let me know. Thank you. Shannon

    1. Hi Shannon, Thank you for your interest! I do not know for certain of the closest Marine Mammal Rescue Center to the Sea of Cortez, but I would recommend contacting the Marine Mammal Rescue Center in Sausalito (since I found a story about them collaborating on a rescue in the Sea of Cortez) to find out if they know of an organization that you could volunteer with:

  7. Hello,
    would this video not be of interest to you – could it be the locals around the SEA OF CORTEZ have no sign postings upon whom to call when finding marine life wounded/in distress? is it too much to ask to call for a vet to tranquillize the shark, doing some wound stitching/supergluing of open wounds with surgical glue/+/-examining the spine with a mobile US scanner – all this can be easily done while this shark was NOT helped – the man recording it is clearly full of ‘Sh*t’ words having his brain not in cerebral thinking mode but in panic mode – so he and his brother could be helped to learn a good lesson here as he is even living local, hanging around with his brother on the beach – while surely he must wonder himself if he has done the right thing by not calling for help…so video is still very fresh, only one month old (June 2017) so can be easily traced up upon.

    title: ‘ Pearson Brothers Winery films 15 ft white shark in 3 ft of water ‘
    uploader: ‘Dale Pearson’ on 3 June 2017

  8. Last night I saw a presentation at the Tucson Sailing Club meeting by Vince Rablich about trying to raise money for a Marine Protected Area in San Carlos’ San Fransiquito Bay to keep commercial shrimping boats from cleaning out the Bay in the east area near the estuary where dolphin, shrimp, turtles and fish gather. Are you helping to raise money for this proposed marine park for tourism? Apparently commercial fishermen have decimated the Dorado(Mahi Mahi) and Marlin populations in the Sea of Cortez. Swordfish and sea turtles are also over harvested and illegal to harvest. All are supposed to be protected, but there is little regulation from Mexican Department of Fisheries and no help from NOAA in US which is the market the fish have been imported to by the millions of pounds despite the Lacey Act which has a provision that says fish caught illegally in Mexico are illegal to import here in the US. Funding Marine Protected areas and enforcing protection would be a start toward reversing the rape and decimation of life in Jacques Cousteau’s former “Aquarium of the World.” A sailing friend made the comment that when he was a boy in the 1960’s, he and his dad set a line off the stern of the boat and within minutes had a fish to eat for dinner. On a sailing cruise in the 1990’s, he caught 1 small fish in three days with a line out all day each day. How do we help protect the Sea of Cortez before it is nothing more than a water filled wasteland?