Madagascar could be a stronghold for ancient fish with a history of 420 million years | Smart News
In the 1980s, when demand for shark fins in Asia increased, fishermen in southwestern Madagascar began casting gillnets in deeper waters. However, instead of mere sharks, the walls of salvaged nets have brought up various Indian Oceans. coelacanths. Unintentionally, the fisherman had discovered a previously unknown population of a fish that can be traced back 420 million years ago. Now, in a March study published in the South African Journal of Science, researchers write that Madagascar could be an epicenter for critically endangered fish and a source for other populations, Tony Carnie reports for Mongabay.
Coelacanths are striking in appearance with distinctive white spots, arranged in unique patterns on each fish, according to Mongabay. Previously, the fish, often referred to as a ‘living fossil’, was believed to be extinct until it resurfaced in 1938 off the coast of South Africa. Since then, fishermen have caught coelacanths off the coasts of Tanzania and the Comoros off the east coast of Africa.
Underwater, coelacanths inhabit submarine canyons at depths between 300 and 1,600 feet. High-tech gillnets can easily reach these depths and, unlike trawls, can be used near rocky environments that fish prefer, Mongabay reports. Coelacanths have poor eyesight and probably cannot detect mosquito nets using electroreception – so they are often trapped inside, reports Stephanie Pappas for Science Live.
When researchers looked at data from accidentally caught coelacanths, they found 34 confirmed captures off the west coast of Madagascar between 1987 and 2019. Experts say the catch is likely much higher based on anecdotal reports from local fishermen, for example Mongabay. Fishermen caught the most fish in Onilahy Canyon, a marine area off the southwest coast of the island, Live Science reports. Researchers hypothesize that the fossil fish originated in Madagascar and eventually spread to the Comoros Islands.
Although a full picture of the size of the fish population is unknown, Mongabay reports, researchers and conservationists call for protection of ancient species. Since the fish take a long time to mature and rarely reproduce, the estimated bycatch is likely to be detrimental to the species. Scientists recommend creating a coelacanth sanctuary in the Onilahy Canyon, adding the fish to Madagascar’s list of protected species and negotiating the management of gillnets where the coelacanth can be found, for example Live Science.
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