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Four-Legged Fish Older Than Dinosaurs Rediscovered in Madagascar

High-tech deep-sea nets used in shark hunting are spelling danger for the coelacanths.

Four-Legged Fish Older Than Dinosaurs Rediscovered in Madagascar
A coelacanth Oceana

The coelacanth, or "four-legged living fossil fish," is a fascinating species: it is bright blue, predates dinosaurs, and weighs as much as an average-sized man. Their shape hasn't changed much in 420 million years, and these critically endangered fish are known to exist off South Africa's east coast.

So when one is discovered alive and kicking, it is bound to make headlines. As demand for shark fins and oil drives fishers to deeper waters in Madagascar, shark hunters are rediscovering previously unknown populations of West Indian Ocean coelacanths and this could be pretty bad news for the species, according to a report from Mongabay News, a nonprofit environmental conservation platform. 

The species was believed to be extinct until 1938, when the first surviving coelacanth was found off the coast of South Africa. Subsequent captures of several others occurred in the early 1950s, proving that coelacanths were in fact not extinct.

Turns out, they are not extinct, but for how long?

Now, these critically endangered species are re-emerging as fishermen use high-tech deep-sea nets in shark-hunting expeditions. Living coelacanths are found in undersea canyons at depths of 330 to 1640 feet (100 to 500 meters), which are accessible to fishermen's gillnets. 

According to a recent study published in the SA Journal of Science, the popularity of shark hunting could be putting the species in jeopardy, especially in Madagascar.

"The jarifa gillnets used to catch sharks are a relatively new and more deadly innovation as they are large and can be set in deep water," the researchers wrote. "There is little doubt that large mesh jarifa gillnets are now the biggest threat to the survival of coelacanths in Madagascar."

The researchers told Mongabay News that they were shocked by the rise in accidental coelacanth captures. A large percentage of the captures were pregnant females, who are thought to produce only 140 live babies over the course of their lives, and although the captured numbers are in the dozens, this is pretty risky for a species classified as critically endangered with a population size still unknown. 

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There are also opposing views, however, with some claiming that catching of coelacanths is too uncommon and that it is unlikely that they'd ever be targeted intentionally.

Nonetheless, the paper, which offers the first systematic description of Madagascar coelacanths, is extremely significant due to the important details it provides on this rare species based on 40 years of research. While banning jarifa nets doesn't seem to be an option at the moment since it would raise a lot of angry noises, the researchers hope that increased research into Madagascar’s coelacanths and new conservation initiatives could be a starting point, because otherwise, this thought-to-be extinct fish could perhaps become now-definitely-extinct in the future. 

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