|The local name for the island chain is Revillagigdeos Islands. The islands lie 250 miles off Baja Mexico's southern shore. These islands are a spectacular magnet for the largest ocean pelagic animals in the world. Schooling Hammerhead sharks, dolphins, silky sharks, Galapagos sharks, clouds of jacks and barracuda, tuna, wahoo, marlin, oceanic white tips sharks, whale sharks and mantas. Mantas are the claim to fame for Socorro Islands; the island on which they seem to congregate the most is San Benedicto! The magical dive site called The Boiler is a submerged sea mount and cleaning station. More than a half dozen Mantas frequent this pinnacle regularly. The Mantas here are the friendliest we have ever experienced, they seem to enjoy the presence of humans. This is truly an exceptional place if you wish to really experience the Manta Magic.
What draws marine life to the Socorro Islands is a wealth of food, namely plankton, along with favorable water temperatures. Year-round temperatures range from 69¡F (owing to nutrient laden up-wellings) to highs of 82. Big animals such as Manta Rays and sharks tend to favor temperatures in the 70 to 76¡F range. Underwater visibility around the islands is customarily 80 to 100 feet but can sometimes fall to 35 to 50 feet where up-wellings occur (sometimes triggering plankton blooms). Unfortunately, for U/W photographers, the big fellows seem to like these areas. When conditions reach their apex, with temperatures in the mid 80s and visibility at 100 feet, the big guys are usually nowhere to be seen;too little food and too much warm water!
Currents ranging from one to four knots, sometimes combined with strong surge from oceanic swells, are a constant in the Socorro Islands. Owing to the locations remoteness and propensity for currents, there is no night diving. Which wild and woolly Socorro Islands dive sites are visited is dictated by sea conditions. The underwater terrain is comprised of either a large submerged ridge, a boulder field on a sloping bottom or huge pinnacles shooting up from the depths. A trademark is the abundance of fish. Two of San Benedictos most prominent sites for manta encounters are the Boiler, a huge pinnacle rising more than 175 feet from the depths and stopping short of the surface, and the rocky, boulder laden shelf of Roca Fortuna.
Hammerheads can also be found here but, as with most oceanic nomads, there is no guarantee. The sites that provide the best odds for encounters include Cabo Pearce and Oneil Rock at Socorro and Roca Partida, a small sliver of rock lying almost midway between Clarion and San Benedicto. Even Roca Fortuna on San Benedictos north side has a few Hammerheads (estimated at 100 to 150 sharks at one time) now and then.