I have been asked on our dive boat trips if we are likely to see a Hammerhead shark. While extremely unlikely at the Catalina Islands dive sites, there is a place in Costa Rica that is famous for them. The probable trigger for these questions is you’ve seen somewhere photos or articles about Cocos Island. If you have seen the opening of the Jurassic Park movie then you’ve an idea of what Cocos Island looks like and of course there are pirate stories linked to the Island and in the past expeditions were sent to look for treasure, which is not legal in case you were thinking about it!
A once in a lifetime trip for divers it’s, rightly on a lot of people’s lists as somewhere they just have to go. It is listed in Top 10s for places divers must visit due to the immense diversity of marine life in its waters. It is a real World Class Dive Destination!
Rising out of the ocean about 550km/342 miles south west coast of the Costa Rican mainland, the island is the tip of an ancient volcano mountain isolated in the Pacific. The only emergent island of the minor Cocos tectonic plate, the only landmark of the vast submarine cocos range.
It was designated as a National Park in 1978 due to its unique ecological diversity and is covered in dense rainforest being the oceanic island with the largest extent of tropical rainforest. It also has permanent fresh water with rivers and streams. The island is 23.85 sq km/9.21sq miles in size with a mountainous terrain which rises to the highest point on Cerro Iglesias at 575.5m/1888ft. It was also designated as a World Heritage Site by UNESCO in 1997 which includes a marine zone of 1997 sq km/771 sq miles.
Having been isolated for so long, evolution has led to endemic species on the island such as the Cocos Cuckoo and the Cocos Finch. Access for civilians is very limited and the only people allowed to live on the island are the National Park Rangers. It is about a 36 hour journey by boat from Puntarenas to get to the island.
The geographical position of Cocos Island is such that it has no protection from the coast and is subject to major oceanic currents of the Pacific such as the North Equatorial Countercurrent, and also sees changeable weather conditions. Scientifically important because of its remoteness, the island is an important ecosystem making up part of the distribution network of migratory marine species in the Pacific. Marine animals come here and gather for feeding and reproduction. There are sites around the island that serve as cleaning stations where marine species can aggregate in order to have the parasites removed from their bodies.
The climate is also strongly influenced by the equatorial countercurrent with an average temperature of about 24C/75F, the island sees a lot of rain with annual average above 6000mm.
From sharks, rays, invertebrates to marine mammals Cocos has the reputation as one of the world’s most bountiful marine sanctuaries.
Cocos island is one of the best places in the world to be able to see large pelagic species. One species people come to see are the schools of hammerhead sharks. Most of us dream of seeing one but here you can see dozens, sometimes hundreds at a time!
One theory points to these aggregations being for mating purposes although it isn’t really clearly understood why it happens but they definitely visit the cleaning stations whilst there. The busy working barberfish and king angelfish get constant food supply at these busy cleaning stations. This unique meeting point between deep and shallow waters brings an abundance like you cannot see elsewhere.
Other shark species you can see include whitetip reef sharks, silky, whale sharks and tigers!
Jacques Cousteau himself visited the island in 1994 and called it ‘the most beautiful island in the world’!
The population densities of large top predators at Cocos Island shows how important this place is and that conserving it is crucial for our marine ecosystems and the conservation of certain species such as the endangered Scalloped Hammerhead Shark. The pelagic species are numerous but also the coral reefs here are very special as they are the most diverse coral reefs of the entire Eastern Tropical Pacific.
This unspoilt paradise is of course under threat. Illegal fishing and poaching are amongst the threats that the island faces despite being a protected area.