Cool critters in the Sea of Cortez
By Shannon Crosby
The Sea of Cortez, which is located in the Gulf of California East of Baja, Mexico, was dubbed the “world's aquarium” by the legendary underwater explorer, Jacques Cousteau. Cousteau used this term because the Sea of Cortez boasts over 900 species of fish and close to 35 species of marine mammals—all located in the tiny gulf between Baja and the Mexican mainland!
This region is so abundantly species-rich because it is the transition zone between the two substantially different ecosystems of the temperate region and the tropics. Therefore, divers can find a combination of whales, rays, nudibranchs, and fish that are commonly found in the tropics AND species that are commonly seen in the temperate waters of Californian Pacific. Here are some of the more sought after critter sightings...
Hanging with a California Sea Lion is one of the most coveted interactions for a scuba diver. This species is known to be extremely intelligent, and can even be taught to perform! For that reason, many people refer to them as underwater dogs. Just like dogs, sea lions can be territorial and aggressive if approached in the wrong way, but if divers are respectful and open they often approach playfully—blowing bubbles, investigating fins or cameras, and sometimes even rolling over for belly pets!
Swimming with these gentle giants is a remarkable experience. Since they are the largest fish known in existence, watching them glide through the water with their large filter-feeding mouths open is akin to the most astonishing dream. As a diver, being around a creature that is so much larger than humans is such a humbling and life-changing experience! Whale sharks frequent the Sea of Cortez because of its mega nutrient-rich waters. As filter feeders, whale sharks are drawn to the plankton populations that are typical for a healthy marine ecosystem like the Sea of Cortez.
Nudibranchs and sea slugs are some of the macro critters that make the Sea of Cortez so exciting—especially since there are tropical and temperate varieties alike! Some of the more commonly spotted species in the Sea of Cortez are: Spanish Shawl (Flabellina iodinea), Flabellina (Coryphellina marcusorum), and Tambja abdere. Nudibranchs are especially cool because many of them ingest the stinging cells of hydrozoids or toxins from sponges to become inedible for their predators! If they do not do this for protection, they often have extremely bright colors to imitate their poisonous counterparts and deter predators from eating them—which makes a really great photo for us divers. Don't forget to be on the lookout for some Nudi-on-Nudi predation! All Nudibranchs are carnivores, and often their favorite meal is a fellow species of Nudi.
There are roughly 8 species of jawfish known to have been spotted in the Sea of Cortez. While many of these are quite small and well-camouflaged, there is one species in particular that is always a pleasure to spot: Opistognathus rosenblatti, or the blue spotted jawfish. This species has beautiful, bright blue dots allowing it to stand out among the other drably colored jawfish that are often spotted in this region. When you spot a jawfish with a mouth full of eggs, it is a truly wonderful day! A fun fact about jawfish is that the males carry the eggs in their mouths until they are hatched—so as soon as the female has laid the eggs, she is off the hook! Some of the photos shown display Opistognathus punctatus, the Finespotted Jawfish, brooding eggs in this fashion.
Are you interested in learning more about the Sea of Cortez? Feel free to read our destination page here: Diving the Sea of Cortez
Would you like to join one of our upcoming Sea of Cortez trip for next year? We charter 2-3 trips a year and they are absolutely fantastic! Checkout our full list of trips here to see if any upcoming dates work for you: Bluewater Trips
2018 we have: