Coelacanth

10/11/20

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Photo by Mark V. Erdmann

Coelacanth

There are only two known species of coelacanth (SEEL-uh-kanth), one of which lives around the Comoros Islands of East Africa and the other off the coast of Sulawesi, Indonesia. It was formerly thought that the coelacanth, previously only known from fossils, had gone extinct 65 million years ago with the dinosaurs. However, in 1938 (and the 1990s for the Indonesian coelacanth) it was found, very much alive. It took this long partly because of their rarity, and partly because they are deep sea creatures that live up to 2,300 feet under the surface. These humongous fish grow to be about 7 feet long, 200 pounds, and can live more than 60 years. Coelacanths are nocturnal and spend most of the day in caves. At night, they hunt and eat bony fishes, cephalopods, and other invertebrates. This fish has some unique features, including a mouth with a hinged joint in its skull allowing it to open its mouth extremely wide; limblike paired lobe fins that move alternately; a type of thick scales unique to ancient extinct fish; a hollow notochord on the spinal cord which is a feature of early vertebrates; and an electrosensory organ used to find food. These features are solely in the coelacanth and do not appear in any living vertebrates. These two coelacanth species and another fish called the lungfishes make a group called the lobe-finned fishes, fishes whose fins attach to short limbs instead of the body. 

Why Are They Endangered?

The coelacanth is ranked as critically endangered and extremely vulnerable to extinction. The main reasons for this is how few coelacanths there are, and how they only live in a small amount of the oceans. They also have really low natural numbers. As technology advances, the coelacanth becomes increasingly threatened by new deep-sea fisheries. Not much is known about the coelacanth’s habits because so few of these animals have been observed, and marine scientists would love to know more about these fish. The coelacanth is also interesting to historical scientists interested in learning how animals evolved to walk on land. Coelacanths have survived for millions of years, and it should not be because of humans that they go extinct.

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The coelacanth's limblike fin                   Photo by Sandra J. Raredon

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The coelacanth is huge!                                            Photo by Sandra J. Raredon

Effects

The coelacanth is a living fossil, making it invaluable to evolutionary scientists wanting to know how vertebrates evolved. There are several hypotheses about what the coelacanth is. It is mostly agreed that coelacanths are bony fishes, not cartilaginous fishes, like sharks. Coelacanths are part of the history of vertebrates, and are closely related to tetrapods. It is thought that the coelacanths, with their limblike fins, are one step along the path that fish took to evolve into animals with legs. The coelacanth is a window into the ancient world of extinct fish, and this fish is invaluable to the study of how animals evolve, and how ancient fish differed from current fish. 

What Can You Do?

The main thing you can do is tell people about this amazing and fascinating living fossil. Not many people know about this animal and its unique and interesting features. If more people knew about the coelacanth, people would be more committed to helping it survive. You can also donate to organizations dedicated to finding innovative solutions to stop bycatch and help people and animals. 

sources cited

Coelacanths. (2018, September 24). Retrieved September 10, 2020, from https://www.nationalgeographic.com/animals/fish/group/coelacanths/

Coelacanth. (2018, December 20). Retrieved September 10, 2020, from https://ocean.si.edu/ocean-life/fish/coelacanth

Coelacanth. (May). Retrieved September 10, 2020, from https://oceana.org/marine-life/ocean-fishes/coelacanth