Scuba diving is by far the most popular water sport that draws first time visitors. Scuba diving and snorkeling in San Carlos can be exciting endeavors given the high-level of diversity in the marine species and the constant possibility of visits by some of the marine giants like whale sharks and manta rays.
This region is comprised of a unique assemblage of species from both the tropical Indo-Pacific and Panamic regions, as well as many temperate eastern Pacific species. Moray eels, groupers, schooling jacks and a wide range of ray species can be seen on most dives.
While the reef fishes provide constant action on every dive, there is nothing like big animal encounters to add excitement to a dive, and big is what the Sea of Cortez is known for. Sea lions are constant and playful companions for scuba divers at Isla San Pedro Nolasco. Curious animals, it is not uncommon to have sea lions swooping through groups of divers, playing in their bubbles and even mimicking the scuba diver’s graceless movements.
At the south tip of Isla San Pedro, deep divers may encounter schools of scalloped hammerhead sharks. Cruise through the cut in the rocks and continue beyond the underwater archway headed south and you may see them at depths between 110 and 150 feet. Occurring intermittently throughout the year, they are most commonly observed in the late fall.
The water conditions in San Carlos can be highly variable depending on the time of year. Summer water temperatures range from 82-88 degrees Farenheit with visibility from 50-100 feet. As the wind and sea current patterns change to winter, cold nutrient-rich waters are brought in, dropping temperatures into the low to mid 60’s and making visibility highly variable. While most scuba divers prefer the warm clear waters of summer, winter diving is excellent in this area. Many species, including various nudibranchs and the brilliantly colored Dall’s (Catalina) goby only show up with the arrival of the deep-water nutrients. Although plankton blooms may occur at any time in the year, they are most common in the early winter or spring when the Sea of Cortez transitions between winter and summer conditions. These plankton blooms may drop visibility temporarily, but they are a blessing, as they provide the base of the food chain for the region.
Formed in a volcanic rift zone, San Carlos sea-bottoms are characterized by the presence of abundant rocks and rubble interspersed with huge boulders and volcanic outcroppings. There is little stony coral in the central Gulf region, owing to the cold winter temperatures, but soft corals such as gorgonians and several species of zoanthids and other anemones are abundant, taking advantage of the nutrient-rich waters. Although the reefs lack the initial wow factor of a Caribbean reef, once you start looking closely at the reef critters, you will be amazed at the quantity and variety of life here, which can be many times the diversity of a Caribbean ecosystem.