Four divers from Cork SAC, Steve Clare myself and Brian went to Cocos Island and Costa Rica in August. Since then quite a few people have been asking me: “when are we going to see your photos from Cocos?”. You see the problem has been that, after my old camera gave up the ghost in 2008 I kinda lost interest in underwater photography for a while, before buying Graham’s old camera to try out an SLR. With one thing and another I only got about half a dozen dives with the SLR before I went to Cocos, and really only decided to bring the camera at the last minute, so I have been a bit shy about showing the photos which I know to be not the best. Nevertheless the dives in Cocos were brilliant and I hope the photos don’t do them too much of an injustice. Anyhow Brian has the better photos, so ask him too!
If you ever saw the start of ‘Jurassic Park’, the jungle covered island that the intrepid dinosaur seekers fly into is Isla Del Coco: or Cocos island. The island, and the waters around it, are a national park of Costa Rica. Eight park rangers and maybe some coast guard are the only residents. To put it in an Irish context, Cocos is about the size of Valentia Island, maybe a bit smaller. It is a thirty six hour boat trip from Puntarenas (The main pacific port of Costa Rica). It is steep with dense foliage, and volcanic in origin. The coastline, apart from a few bays, consists mainly of steep cliffs down which numerous waterfalls cascade. According to Wikipedia it gets an an average annual rainfall of over 7,000 mm (275 in). That is about seven times the annual rainfall that Cork gets. There is a dry season and a wet season. We went in the wet season. The boat has a rainwater collection system. Long hot showers are not a problem, the tap water is drinkable, and unique in my experience of liveaboards elsewhere: in Egypt or Australia; there is a laundry service aboard ! But it didn’t rain that much, a bit for the first few days, the sea was 27 to 29 degrees C, and we were glad of a bit of cloud cover because when the sun shone it was almost too hot. All the waterfalls are very atmospheric, like a lost world, but the amount of fresh water during the wet season tends to affect underwater visibility a bit. Dry season it seems is clearer but with fewer fish.
Enough about annual rainfall and laundry, what about the sharks? There are many to see, on every dive, and sometimes your field of vision is filled with them. So dense that the hammerheads almost look like flocks of birds wheeling and swooping above. Not just Hammerheads, but also silver tips, white tips, black tips (which we didn’t see), galapagos sharks, silkies (which kinda look like galapagos sharks except to an expert), whale sharks (which another boat saw). The difference between white tips and silver tips is that white tips have white tips just on dorsal fin and top of tail and are smaller, silver tips are larger and have a silver trailing edge to all their fins. I have seen big sharks before, even hammerheads, but never the huge schools that you see at Cocos. Plenty of rays too including manta, marble ray, and mobula. The usual reef wildlife that would amaze you elsewhere: moray, turtles, lobsters and all, seem almost to be bit players, with the sharks as the stars of the show.

It’s not a place for a novice. The sharks like a current. The morning dives are about 30 meters, or a bit deeper. Nitrox was used by everyone aboard 32% by default. All the dives were from the two ‘pangas’: glass-fibre-hulled boats about 10 meters long with two 110 HP outboards. A bit like a RIB without pontoons. At the outset we were divided into two groups and did all the dives except night dives with the same team. A friendly rivalry built up with each panga wanting to see the best stuff that day. The currents at the best sites are moderate to strong, and there can be a surge and waves. Not quite as frantic a fin as for example: the Brothers Islands Egypt, or even Malin Head Donegal, or the Ling Rocks on a misjudged spring tide, but the technique is the same. For most morning dives backward roll negatively buoyant off the panga and fin like hell for the bottom, meeting your buddy at about 10 meters on the way down. On some dives (Alceon and Punta Maria) a shotline is used, the panga is tied on, and if the current is very strong a line is brought back so that you hold it as you enter, then pull hand over hand to the shot.
Hammerheads are very polite sharks. They hunt offshore at night and school near the island during the day waiting to be groomed at cleaning stations manned by barberfish and king angel fish. They are not afraid of divers but if they see a you in the cleaning station they assume that you are being groomed and wait their turn to enter. Therefore if you want to see one close up you have to hide behind a rock, with the barber fish in front and the hammerheads coming in from the blue to be cleaned of parasites. This means that you have to creep about on the bottom from gulley to gulley like some kind of underwater apache, trying not to kneel on an urchin or the head of a moray.
On about half the dives you dive to the cleaning station to watch the sharks, then as the NDL gets low begin to ascend. Most other places in the world that would be it. But at Cocos, divers tend to do an very prolonged safety stop at six meters or maybe a bit deeper, drifting for twenty or thirty minutes in the blue, because you never know what you might see. A baitball or just a school of fish to drift through. Maybe a marlin or barracuda. There is a pod of bottlenose dolphins resident year round and these might be seen on any dive. Dives in excess of fifty minutes are normal, the water is warm and people don’t want to surface in case they miss something spectacular.
Alceon (named after one of Jacques Cousteau’s research vessels) became a favourite site with us. One of our best dives , with dolphins at the end was at Dirty Rock. Personally I really liked the larger of two side-by-side sea stacks: ‘Dos Amigos, Grande’ which has a large tunnel at one side filled with marble rays. Just lie at the bottom on the sand and the rays swoop around you very close, but hard to photograph because of the contrast of light and shade. Everyone’s favourite night dive was at Manulita coral where the white tips hunt alongside jacks as a large pack, wriggling in and out of the gaps in the coral flushing fish out of their sleeping places then mugging them. It can be comical when several of them get stuck in a gap and one has to reverse out before the rest can free themselves.
We visited the island one afternoon for a change, and hiked up to a waterfall above the hydroelectric dam that provides the ranger station with it’s power. After a swim to cool down we returned to the station where the rangers were keen to show us the collection of confiscated netting, hooks and even a drug running boat. They have constructed a suspension bridge out of seized fishing gear.
The thirty six hour boat trip might seem a bit daunting but there were things to see and do. On the way out we had fun watching a red footed booby that would patrol above the bow of the boat waiting for flying fish to leave the water to escape the bow wave. The booby would then swoop down and try to catch the fish in mid flight. As we arrived at Cocos we awoke to the resident dolphins fishing around the boat for about an hour. On the way back, humpback whales (a mother and calf) kept us entertained for a while.
We dived with Undersea Hunter, which was also the name of the liveaboard. The staff and the other passengers were delightful, the food was very good, the boat and facilities were excellent, and the setting idyllic. A point to note is that diving in and around baitballs has recently become illegal in Costa Rican waters. Also following from a number of incidents the Undersea Hunter group didn’t accept rebreathers when we were booking (not that any of the four of us uses one, just other divers in the club do). The diving probably isn’t really very suitable for rebreathers anyway due to the currents surge etc.