Frilled shark
© Citron / CC BY-SA 3.0

Rare “prehistoric shark” found off the coast of Portugal

By: Irene Lorenzo
Date posted: 14 November 2017

Researchers have accidentally captured a frilled shark, a “living fossil” dating back at least 95 million years. The prehistoric fish was found in a pile of unwanted catch, where it unfortunately died shortly after being caught.

Frilled shark
© Citron / CC BY-SA 3.0

Although they have been recorded in deep seas worldwide, including off the coast of Scotland, records are patchy and we do not know about their population trends

Dr Peter Richardson,
Head of Ocean Recovery
Marine Conservation Society

Scientists from Portugal’s Institute for the Sea and Atmosphere were conducting a European Union project to minimise the incidental catch of marine animals in commercial fisheries, known as bycatch, when they came across one of the world’s rarest deep water sharks off the Algarve coast in southern Portugal. Although the fish was found last summer, the news are now making the rounds this week. But what do we know about this shark and how rare is it to capture one?

The truth is that little is known about the lifecycle of this this unusual snake-like fish, which is why the researchers kept the specimen for further study. What we do know is how it looks like: 300 needle-sharp tricuspid teeth in 25 orderly rows that give them a bit of a terrifying look. Their strange teeth are presumably useful when it comes to catching fast moving slippery prey – squid, large fish and even smaller sharks.

Researchers refer to it as a “living fossil” as it has barely changed in millions of years which means it was swimming around the deep ocean around the time of the dinosaurs. Perhaps unsurprisingly, since they’ve barely changed, they do look very different to most of the sharks we’re used to seeing as they belong to a more primitive family of sharks.

No accurate global population estimate is available for this species as it’s difficult to quantify how many of them are alive, but based on their strandings they seem to have a patchy but global distribution, which is why the International Union for the Conservation of Nature (IUCN) lists them as a “Least Concern” species – they are not globally threatened.

Very little is known about these fascinating, prehistoric creatures. Although they have been recorded in deep seas worldwide, including off the coast of Scotland, records are patchy and we do not know about their population trends”, said Dr Peter Richardson, Head of Ocean Recovery at the Marine Conservation Society.

Like with other deep water fish, the biggest threat is the accidental catch in various types of fisheries such as deep-set gillnets, longlines and bottom trawls. Once they are accidentally caught, they are used for fish-meal, discarded or kept for research as was the case with this recent find.

Deep-sea fishing presents the greatest risk, and many countries where frilled sharks have been recorded, including the EU, have measures in place to manage or ban deep sea fishing. These restrictions offer important protection for our precious deep-sea natural heritage, but we should remain vigilant over the potential impacts of any other deep sea industries”, explains Dr Richardson.

The Marine Conservation Society campaigns for offshore marine protected areas to protect species living in deep water habitats such as the frilled shark. Measures taken to improve the management of deep water fisheries as the ones being trialled by these scientists would be beneficial to the population of these sharks and other fascinating deep sea animals.

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