Diving with Schools of Hammerhead Sharks in Cocos Island

Photo courtesy from Dive and Boats

Among the world’s dive site, there are several spots who features a signature species in which you are guaranteed to encounter underwater. Some sites may feature small critters that has become an underwater photographer’s paradise. But here in Costa Rica, what we feature are the big boys of the deep. So get ready as we take you to a tour at a remote island located 342 miles (550 kilometers) from mainland Costa Rica and try one of the famous dive experiences in the world: diving with not just one, not just five or ten but hundreds of hammerhead sharks in Coco’s Island.

Presenting to you our featured species:

Scalloped Hammerhead Shark (Sphyrna lewini)

Max. length: 430 centimeters
Ave. length: 300 – 360 centimeters
Size at 1^st Maturity: 225 centimeters
Maximum weight: 150 kilograms
Depth range: 0 – 1,000 meters
a value: 0.01260
b value: 2.810
Frequency: Threatened due to shark finning, can be found in all the world’s tropical waters.

Photo courtesy from Mission Blue

I think we don’t need to expound on how to easily identify a hammerhead shark courtesy from its uniquely hammer-shaped head. But what we would like to narrow down is how to differentiate a scalloped hammerhead to other species of hammerhead sharks present in Coco’s island and the rest of Costa Rica.

Let’s go directly to its obvious part – the head. The Great Hammerhead Shark (Sphyrna mokarran) and the Smooth Hammerhead Shark (Sphyrna zygaena) are relatively huge in size with a pronounced central notch at the head. The shovelnose or bonnethead hammerhead shark (Sphyrna tiburo) is the only species of hammerheads that has a semi-circular shaped head.

Photo courtesy from www.weebly.com

A Scalloped Hammerhead Shark has medium-sized body similar to a bonnethead but has a lesser pronounced central notch at the head. Another thing to note: as far as Costa Rica is concerned, it’s only the scalloped hammerhead shark that congregates in huge numbers that usually goes over one hundred individuals.

Dive Sites in Cocos Island Popular for Hammerhead Sharks

While hammerhead sharks patrol the surrounding waters of Coco’s Island, there are some dive sites that are especially known to house a huge congregation of hammerhead sharks as cleaning stations are strategically located in these sites.

Here are some dive sites in Coco’s Island popular for hammerhead sharks.

Bajo Alcyone

You will start your dive by descending to this fairly exposed seamount that goes all the way down to 40 meters (130 feet). As mild to moderate currents are present, you will do an anchor line descent until you reach the reef and start your journey towards the cleaning station.

Photo courtesy from divescover

The usual scenario on this particular dive is you will position yourself looking to the deep blue open water while holding to a rock or any solid object. The first appearance of hammerhead sharks will come from a distance and eventually goes near the reef where you are situated. Once the school of hammerhead is within the vicinity of the reef, you will be amazed by its huge number where the word “continuous swim-bys” is one of the common observations written in a dive log.

For more information, please read our related article on Bajo Alcyone.

Dirty Rock

Photo courtesy from Matthew Meir-PhotoShelter

Similar to Bajo Alcyone, you will start your dive with an anchor line descent where you follow and traverse a vertical rock that drops down up to 35 meters (115 feet). This site is considered an established cleaning station where you can see lots of Black-nosed Butterflyfish (Johnrandallia nigrirostris) or commonly called as the barberfish which is the main actor in cleaning the hammerhead sharks.

Some divers have discovered, during their multiple trips to Coco’s Island, that there is no need to go deep for a hammerhead shark interaction can occur just at the start of your dive and as shallow as 20 meters (60 feet) where light and visibility is much better compared to deeper areas.

For more information, please read our related article on Dirty Rock.

Dos Amigos

Photo courtesy from IUCN

Aside from hammerhead sharks, what is amazing with Dos Amigos is the underwater formation of rocks where you will start by entering an archway that leads you to a cleaning station. Just imagine that the archway is just like a huge underwater welcome billboard where cleaner fish and pampered hammerhead sharks awaits your presence. This is also one of the sites in Coco’s Island where you can see some hammerhead sharks that are motionless, or as they say it in a state of trance, while they are being cleaned of dead skin and parasites.

For more information, please read our related article on Dos Amigos.

Dive Companies offering Liveaboard Cruise to Coco’s Island

Due to the relative distance of Cocos Island from Costa Rica’s mainland, the only way to fully explore its underwater habitats and dive with hammerhead sharks is by signing up with a liveaboard cruise.

Here are some of the Scuba outfitters in Costa Rica that offers a week-long of diving in Coco’s Island.

The Undersea Hunter Group

Having two well-maintained ships, the Undersea Hunter Group is one of the few dive operators offering liveaboard cruise to Coco’s Island. On the day of your departure, you will be picked up from your hotel anywhere between from 8am to 1pm and take a 3 hour drive going to Puntarenas where your vessel is waiting.

M/V Argo

Photo courtesy from Undersea Hunter Group

This latest vessel of the Undersea Hunter Group is a mixture of a working boat and a luxury yacht. Aside from the 14 – seasoned crew that will man the ship, this 130-foot vessel can accommodate 16 dive guest where you can stay and sleep in its spacious cabins. Aside from the three 24-footer skiffs that will serve as your tender boat during a dive at Coco’s Island, it has an onboard Remotely Operated Vehicle (ROV) that can explore deeper site while breaching the limits of human capacity.

M/V Sea Hunter

Photo courtesy from Undersea Hunter Group

Redesigned and configured to become a hybrid, this vessel has a large platform equipped with powerful machinery while the interior offers the comfort of a modern yacht. The 10 cabins can accommodate up to 20 dive guest where this spacious boat has an individual gear storage, camera and strobe shelves with both 110 and 220 voltage power outlets.

For more information, you can read our related article about the Undersea Hunter Group.

Okeanos Aggressor

Photo courtesy from Aggressor Fleet

This vessel is designed to give scuba divers the best experience they can have while diving at Coco’s Island with the Hammerhead Sharks. They focus on quality diving and safety precautions during your entire stay with them. Their 14 dive guest (maximum per trip) will be looking forward to a week-long of diving in Coco’s Island where you never get back to the mainland without a close encounter with hammerhead sharks.

Before your liveaboard cruise, you will be met by their staff for briefing and orientation of what to expect during your trip to Coco’s Island. You will be provided with transportation in picking up and sending you back to your hotel after the trip.

Reference:

Fishbase: www.fishbase.org

Undersea Hunter Group: www.underseahunter.com

Dive the World: www.dive-the-world.com

About Tristan Paylado
Tristan is a marine biologist and a CMAS 2-Star Dive Instructor
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