Sunday, December 27, 1998 – Isla del Coco

G’day all

Well it is 22:00 on a Sunday night in Costa Rica. I trust you all had an excellent Christmas and enjoyed John’s missive. Yesterday and today have been heavy dive days. The trusty tender has been busy and in good hands, courtesy of our top panga driver Monyo. We have all averaged about three dives a day to date. They all have their special moments, but the general trend is sharks and schools of pelagic fish.

Yesterday we visited a dive site called Alcyon, which is a deep seamount and often the home of large schools (+150) of Hammerhead sharks. We did not see huge schools, though there were at least always 8-10 around. Seeing them is one thing, but capturing them on video is completely a different kettle of fish. They are very skittish and do not seem to enjoy being around divers all that much. There is also plenty of current around which is great for fish life put hard going when you always have to fight into it. You see, fish tend to congregate up current and as divers with all their gear are hardly very streamlined, it takes effort to stay in one place, let alone move forward. Not that I am complaining! I must say though, I do miss the colourful corals of the tropical Pacific.

Today we had a special treat. On the way back from the morning dive, Monyo spotted birds and dolphin working the sea. We all jumped back in and had the treat of a lifetime. Twelve dolphins frolicking among us, along with a multitude of Whitetip sharks (Triaendon obesus), Blacktip sharks (Carcharhinus limbatus) and Silky sharks (Carcharhinus falciformis) feeding. This is the sort of stuff that I expected of Cocos. More please.

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Bottlenose dolphins put on a performance for the silky sharks, blacktip sharks, and us

Besides the usual tourist attractions, STARSHIP has also been involved in a little science. At various times all of us have been trying to assist John in his fish collecting. It may not be as exciting at times, but it is rewarding to think that we may actually be doing something of meaning as well. Yesterday John had a particularly good day. He shall let you in on it in person…take it away John.

Thank you Rich. As I mentioned in an earlier entry that Cocos Island, because of its distance from the shore, has unique species of birds, plants, and shore fishes that somehow made it to the island, found themselves marooned, were lucky enough to survive and reproduce. The progeny of those plants and animals can over time evolve into novel species, particularly if the event of their ancestral arrival is so rare that they have an opportunity to reproduce in isolation, allowing natural selection to reward those with traits adaptive to Cocos Island. Or so Charles Darwin and his successors suggested – and they were right! Case in point, the Cocos Island Batfish. Upon our arrival, we asked Avi Klapfer, an experienced underwater Cocos dive tour operator, to keep a sharp eye out for Ogcocephalus porrectus. I was familiar with another batfish, that of the Galapagos Islands (Ogcocephalus darwini), which is better known than its Cocos relative. Ichthyologists are interested in the ancestry of both species – what they evolved from, how they are related to each, and how on earth they got to Cocos and Galapagos islands, respectively. At this point there are very few specimens of the Cocos species and none of its DNA is available for study.

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The unimaginable and unforgettable face of a Cocos Island rosy lipped batfish

Now back to the point of this story. Avi knew that it could be found in water as shallow as 20 m (60’) in March, but at this time he said it was unlikely that we would see one. We made a special effort to dive at Lobster Rock, an offshore platform that rises to 10 m (30’) and slopes off into the gloom on all sides. As we descended we could see the rippling effect of the cold water thermocline coming up to meet the warmer surface layer at about 15 m (45’), and swimming through it was like entering a walk-in freezer – it was cold! We spread out and searched, and at the end of the dive were rewarded to see Avi shivering and grinning, with a batfish in hand.

The Batfish is about as large as your open hand, is nearly flat on top, has a long snout that looks like a miniature unicorn’s, has whiskers on its chin, and has its pectoral fins splayed to the side such that it looks like a road-kill Frogfish. (If you don’t know about Frogfish, visit your local aquarium or library, and stay tuned for future journal entries.) If its shape isn’t strange enough, its coloration is even better. It has bright red lips! This fish is so clumsy in appearance and locomotion that a human can pick it up underwater. I often wonder how any fish can be so slow can survive, so as a general rule I carefully examine such species. I look for venomous spines or dangerous protuberances, and lacking them, I presume that there must be some chemical defense that the beast employs or it would soon have become extinct. The batfish has a leathery, almost sandpaper rough skin, but that is hardly a defense. I cautiously licked the skin to see if there was a strongly distasteful slime that would cause me (or a grouper or a snapper) to spit it out, and found none. In that it is our only specimen and they are so rare, I didn’t filet it and dine on it a la fugu, because that would be both unscientific and contrary to our permit. So, we carefully photographed the batfish, watched the it in the aquarium, and will ultimately preserve some of its tissue for DNA analysis and the remainder will reside in formaldehyde in a jar on the shelf of the fish collection of the California Academy of Sciences in San Francisco. If you are a scientist that wants to compare your Batfish to ours, give us a call.

Thanks John! Besides all this diving and science, we are also finding time for some socializing. As there are two other boats here, we have been inviting guests and being invited. As always DJ has been cooking up a absolute storm. We got out the old card game last night which was good, as it has been a while since we have all been up and doing one singular activity as a unit. So yes, morale is good and Cocos is fantastic.

Best regards

Rich