What are Coelacanth?
The fish that 'outdid' the Loch Ness Monster
Coelacanths were first described by Louis Agassiz in 1836 from a 260-million-year-old fossilised fish tail. Coelacanths, extinct and extant, belong to a group known as lobe-finned fishes (Sarcopterygii). They have multiple fleshy, limb-like fins that would be use to walk on the sea floor.
The paired fins move in a coordinated way, unlike in other fishes. The diagonal pelvic and pectoral fins work in tandem, like the leg movement pattern of a walking reptile.
Coelacanths have also been observed performing 'headstands', rotating their body to be vertical in the water and holding this position for several minutes. This behaviour is linked to a rostral organ in the head that is thought to detect the weak electrical impulses of prey.
Location
Coelacanths are known primarily from the Comoros Islands, which are situated in the Western Indian Ocean between Madagascar and the east coast of Africa, but also live elsewhere along the east African coast and in Indonesian waters.
Are coelacanths endangered?
Coelacanths were once considered insignificant as food and were typically released when caught by fishermen. However, with growing scientific interest, these fish became targeted specifically.
Previously, fishermen in the Comoros Islands were generously rewarded for reporting their coelacanth catches. Consequently, there was an abundant supply of specimens available for comprehensive studies. Additionally, surplus fish became official gifts from the Cormoran Government.
Despite their short lifespan outside their natural habitat, coelacanths remained in high demand and became a lucrative commodity. This led to the emergence of a black market, with aquariums eagerly seeking these elusive creatures, despite the challenges of keeping them alive.
Reports from 1952 suggest that London Zoo was willing to pay £1,000 for a specimen, and in 1989, the Toba Aquarium in Japan faced criticism for a £1.3 million project aimed at capturing live coelacanths. By 1992, coelacanths were listed on illegal trade markets at £100,000 each.
Living Fossil or Not?
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Alongside lungfish, they stand as the closest relatives to tetrapods, sharing several morpho-anatomical traits not present in more distantly related vertebrates like ray-finned fishes.
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Researchers revealed in a recent study of these large, nocturnal deep-sea creatures that they possess a lifespan approximately five times longer than previously estimated — around a century — with females carrying their young for five years, marking the longest gestation period known among any animal.
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According to the fossil record, they were previously believed to have disappeared during the mass extinction event that eradicated roughly three-quarters of Earth's species following an asteroid impact at the conclusion of the Cretaceous Period.
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References
CBC/Radio Canada. (2021, June 22). “living fossil” fish surprises scientists with 100-year lifespan | CBC News. CBCnews. https://www.cbc.ca/news/science/coelacanth-fossil-1.6074328
Coelacanths: The fish that “outdid” the loch ness monster. Natural History Museum. (n.d.). https://www.nhm.ac.uk/discover/coelacanths-the-fish-that-outdid-the-loch-ness-monster.html#:~:text=The%20unexpected%20capture%20of%20a,history%20discovery%27%20of%20the%20century.
McGrouther, A. M. (n.d.). Coelacanth, Latimeria Chalumnae Smith, 1939. The Australian Museum. https://australian.museum/learn/animals/fishes/coelacanth-latimeria-chalumnae-smith-1939/