(08-03-10) It is a wild and lonely place, where great findings are still possible, with rich and different waters, little known and not crowded. We are talking about the Sea of Cortez.

    The Baja California Peninsula extends like a big appendix of the American continent, penetrating into the Pacific Ocean, where it creates an inland sea 800 miles long. It was discovered by Núñez de Guzmán, an officer of the expedition of Hernán Cortés, after whom the region was named.

    The Sea of Cortez represents one of the most interesting marine ecosystems in the world, and also one of the most productive. More than 600 marine species have been surveyed here, from which more than 200 are fishes and almost one third of the cetaceans of the world, such as the giant blue whale can be seen here.

    This entire area is geologically young and active. We are at the end of the famous San Andreas Fault. It is an area of active underwater volcanism, with several vents and deep depths that can reach 3,660 meters in the deepest.

    All this along with the underwater terrain and the different regimes of streams cause major upwellings of water that is cold, rich in nutrients, capable of feeding great shoals of fish feed as well as the large filter feeders of the ocean.

    Despite his position it is not an ocean reef. Temperature fluctuations and sediment flow especially in the northern part, contribute to it. However, we can observe small coral reefs, islands in which multicoloured life appears, with its classic inhabitants. This, together with the typical fauna of the tropical Pacific, creates a mixture really unique.

The islets of Espiritu Santo

    One of the great attractions of the Sea of Cortez is the presence of sea lions (Zalophus californianus). The islets are one of the most classic dives in the area. They are some rocky outcrops located on the northern area of the Island of Espiritu Santo. Its silhouette looks like an old castle in ruins.

    Near the rocks we can see come sea lions that lye comfortably on the stones, placidly sunbathing. The animals are very used to human presence, although we must be careful because the younger ones are very playful and can even remove our glasses.

    The dive is simple and takes place at shallow depth. It is, simply, to be carried away by the curious behaviour of sea lions. It's amazing to see them evolving in their environment, away from the grotesque spectacles to which they are subjected in captivity.

    Males excel at their large size and prominent head. They often appear to mark territorial boundaries, throwing perfectly audible grunts underwater, and expelling bubbles. In most cases they have no great significance, except in mating season, which for obvious reasons sea lions become more aggressive and it is better to avoid them

"EL BAJO"

    Each diving area has a particularly famous point that in some cases becomes mythical. In the Sea of Cortez that honour goes to El Bajo. As its name suggests it is a small mountain range that begins in the middle of the sea floor. It is located 8 miles northeast The Islets. Its access from La Paz will take between two hours and two hours and a half. The approximation is always spectacular either going for the Islets or going along the island of Espiritu Santo in its eastern side.

    The structure of the dry is longitudinal, in a north-south alignment about 500 m. It has two peaks at the ends and a sort of valley in the centre. The depth in the highest area is at about 16 meters, while near the bottom it reaches 40-50 m, and later it falls sharply.

    Its fame has grown due to the numerous underwater documentaries that have been developed here by American filmmakers as Howard Hall and Marty Snyderman. In El Bajo, we could say, any finding is possible, although their big stars are the hammerhead sharks that congregate here.

LOOKING FOR THE HAMMERHEAD SHARK

    In fact, a numerous population of hammerhead sharks (Sphyrna lewini) lives here. Depending on the season, these sharks can be found in different depths and in different places. It still remains unclear the reason of these congregations, but what is true is that if we are lucky this will be an indelible vision for the retina of any diver.

    We have to avoid big groups and unnecessary noises because, despite their fierce appearance and bad reputation, they are extremely timid animals that avoid at the slightest alarm.

    But there are not only hammers in El Bajo, there are many great species here: whale sharks, marlin or large makos are common, as well as manta rays. Meeting this last animal is probably one of the sightings most desired by all divers. We can see here from the large manta rays (Manta birostris) to different species of mobulas (Mobula sp). Both are all the year round, although they are more frequent when there is more plankton. La Reina, located in the north of the island Cerralvo is a good place to meet them, but they can also be seen at the bay of La Paz.

    The large amount of plankton in the area we said above is the great cause of its peculiar biological richness. With this concentration it is normal to see large animals that feed on such a tiny dish, especially one as elusive and mysterious as is the whale shark (Rhincodon typus).

    These giants often wander around the Sea of Cortez, but it is in the Bay of La Paz where meetings are more frequent, and where they have their residence for some time.

WRECKS, REEFS AND FISH

    After the great emotions, it is good to have some relaxation. We also have places for a calmer diving, but as well interesting, where we can watch the many amazing animals of this sea. A good opportunity to do this is to dive in the various existing wrecks around La Paz.

    Some chips have been sunk to attract marine fauna, Duch as the Aquarius, the Lapas 03 ot the Barco Chino, and others sunk accidentally, as the Salvatierra. All of them are easy dives with great abundance of life.

    It is especially interesting the Salvatierra. It is a ferry sank after a collision with the reef Swanne on the way to the port. This elongated and shallow reef is a real oasis for life and a sample of coral diversity, not very common in the area.

    We could say that there is not a single rock or a crack that is not colonized: corals (like the endemic black coral with yellow polyp Antipathes galapagensis), gorgonians and sea sponges compete for the place, while many fish swim over here.

    Several species of moray eels can be seen here, groupers with incredible colours and maybe, especially, angel fish, such as the king angelfish and above all the Cortez angelfish (Pomacanthus zonipectus), which is endemic to the area and a true symbol of this beautiful and wild sea.

Text and Pictures: Juan Carlos García