/// The Coelecanth, Living Fossil in Bunaken

08 Dec / 2011
Author: Two Fish Blog Tags: Comments: 1

Coelecanth is a Devonian lobed fin fish that thrived in the oceans 450-500 million years ago. Its importance lies in the fact that it is considered the “missing link” between fish and animals, ie they were the ones that crawled from the waters to create life on land. It is also an inhabitant of Bunaken Marine Park, and probably one of the most unusual inhabitants at that!

It was thought that the Coelcanth disappeared along with the dinosaurs over 73 million years ago. Then one of the biggest scientific discoveries of the 20th century happened when Marjorie Latimer, who worked at the local museum in East London, South Africa found a Coelcanth on a local fishing boat. Later more were discovered in the Comoros Islands in the Indian Ocean, and they have since been have been found in the waters of Kenya, Tanzania, Mozambique, South Africa, and Madagascar.

The Coelecanth is nicknamed the “living fossil”, and in 1997 it was discovered in a local fish-market in Manado, and later in 2009 it was videoed by a japanese team of divers around Manado Tua in the Buaken Marine Park.

During the daytime, the Coelecanth rest in caves anywhere from 100–500 meters deep while others migrate to deeper waters. With steep underwater, eroded volcanic slopes covered in sand that also house an obscure system of caves and crevices, the topography of the Bunaken Marine Park is therefore an ideal habitat for the Coelecanth.

The word coelacanth literally means, “hollow spine,” because of its unique hollow spine fins. Coelacanths are large, plump, lobe-finned fish that grow up to 1.8 meters. They are nocturnal drift-hunters. The body is covered in cosmoid scales that act as armor. Coelacanths have 8 fins – 2 dorsal fins, 2 pectoral fins, 2 pelvic fins, 1 anal fin and 1 caudal fin.

Locomotion of the coelacanths is unique to their kind. To move around, coelacanths most commonly take advantage of up or downwellings of the current and drift. They use their paired fins to stabilize their movement through the water. While on the bottom of the ocean floor their paired fins are not used for any kind of movement. Coelacanths can create thrust for quick starts by using their caudal fins. Due to the high number of fins, the coelacanth has high maneuverability. Coelacanths can also orient their bodies in any direction in the water. They have been seen doing headstands and swimming belly up. It is thought that their rostral organ helps give the coelacanth electroperception, which aides in their movement around obstacles.

Coelacanths are usually caught when local fishermen are fishing for oilfish and sharks. Fishermen will sometimes snag a coelacanth instead of an oilfish because they usually fish at nighttime when the oilfish (and coelacanths) are feeding. The coelacanth has no real commercial value, and as a food it is almost worthless as its tissues exude oils that give the flesh a foul flavour. Before scientists became interested in coelacanths, they were therefore usually just thrown back into the water if caught. Now that there is an interest in them, fishermen trade them in to scientists or other officials once they have been caught.

Scuba Diving (open circuit and closed circuit) expeditions for the Coelacanth have been successful in South Africa where Coelacanths were identified off the continental shelf near Sodwana Bay at depths between 90-110m. These depths are with the limits of experienced technical divers either on open or closed circuit scuba. Rebreather diving would be optimal regarding gasses and bottom times.

Two Fish Divers are also offering similar expedition dives for Coelacanths in Bunaken Marine Park via our TEC diving services headed by Brendon. No one else has ever offered this kind of diving opportunity in this area that have the facilities, equipment and experience to pull it off… Until now!

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