Among the parade of pelagic species seen at Socorro Island are schools of hammerhead sharks. They are most often spotted at the dive site Roca O’Neal.
Perpetually cloudy and rainy, Cocos Island is always humid with an average temperature of 80°F (27°C) and an average annual rainfall of over 7 meters. Water temperature ranges from 75-84°F (24-29°C) year-round. It’s important to note that thermoclines create up to a 6 degree Celsius drop in temperatures during any season, so be prepared with the correct exposure gear.
Dry months are considered to be between December and May although it still rains during this time. For divers who suffer from seasickness, this is the best time to dive in Cocos Island. The surface is calmest during these months making the long journey to this remote seamount a lot smoother than during the summer months. Visibility is also at its best during the winter months.
However, because the number of pelagic species decreases during the winter and spring months, many liveaboards stop traveling to Cocos or split their time between Cocos and other Costa Rican routes.
June to November is the rainy season, and in many people’s opinions, is the best season for diving in Cocos Island. At this time, nutrient upwellings attract the large number of hammerhead sharks Cocos Island is famous for. Manta rays and whale sharks are also more frequently spotted from June to November.
Because of the large amount of plankton in the water, visibility during this season drops to about 45 feet (15 meters) and topside conditions deteriorate. The journey to the island is much rougher during the summer.
This is also high season for diving trips to Cocos Island, so make sure to book as far in advance as possible.
Of the 20 dive sites at Cocos Island, Bajo Alcyone and Dirty Rock are the most famous. Beginners should dive Dirty Rock; advanced divers can try Bajo Alcyone.
Cocos Island is most famous for its huge congregations of scalloped hammerhead sharks. These sharks come to the island to feed and also to visit cleaning stations. A particular favorite cleaner of the scalloped hammerhead shark is the black-nosed butterflyfish, otherwise known as the barberfish.
Also expect to see mobula rays, manta rays, and the occasional whale shark coming to feed in the nutrient-rich waters. Along the boulders, find marble rays and spotted eagle rays hunting and whitetip sharks resting in the daytime. During night dives, whitetip sharks become active and you might be able to witness a feeding frenzy. Other sharks to look out for at Cocos Island include the Galapagos shark, silky shark, silvertip shark and if you are lucky, the tiger shark.
Along with the sharks are mammoth schools of bigeye trevally, snapper and grunts.Traveling deep into the ocean in the submersible, you might be able to catch sight of the endemic rosy-lipped batfish and benthic sea creatures.
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