Indonesia: home of living fossils

 

Photograph by Dr Mark V Erdmann

Indonesia’s waters are filled with fascinating life – from the exquisite corals around Raja Ampat, an area celebrated as the global epicentre of marine diversity, to the black-sand bay off Sangeang Api, where tiny bubbles of gas rise from the centre of the earth, tell-tale signs of the island’s position on the Pacific Ring of Fire.

The country’s waters are also home to one of the most endangered species on earth: the coelacanth, a fish sometimes described as a “living fossil” due to its prehistoric appearance. According to experts, this fish evolved into its current appearance about 400-million years ago.

Coelacanths were thought to have become extinct 66-million years ago, but in 1938 a museum curator found a Latimeria chalumnae – a type of coelacanth – that was part of a fisherman’s catch off the east coast of South Africa.

In 1997 a second species of coelacanth, Latimeria menadoensis, was discovered, this time in Indonesia. Dr Mark V Erdmann, who is now one of the world’s leading tropical scientists, was on honeymoon in Manado, north Sulawesi, when he and his wife, Arnaz, saw a strange-looking fish being taken into a fish market. They managed to get a photograph of the coelacanth before it was sold, and it would be a year until they found a live specimen, and were able to confirm the find of the new species.

Coelacanths are large, plump fish which grow to about 2,2 meters and weigh about 100kg. During the day they rest in caves and crevices between 100 and 250 metres deep – coelacanths need cold water to survive. At night they swim along cliffs and reefs with their heads low – almost like they’re doing a headstand – and feed on fish that live near the bottom of the sea. They have big eyes, and extrasensory organs in the head, like sharks do, so they can sense where other fish are (which is why they swim in a “headstand”). Although their mouths are small, coelacanths are able to hinge both upper and lower jaw, to open their mouths wider.

Female coelacanths keep fertilised eggs within their bodies, and gestation is around one year. While some scientists say coelacanths live to just over 20 years, there are many who argue these fish can live for about century.

Scientists say that there are likely between 210 and 500 coelacanths on the planet. If you see one on one of your dives with us, you will be very, very lucky.

Interested to hear more about the coelacanth? In the video, below, Dr Mark V Erdmann, discusses the fish he “discovered”.

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