Far from the tumults of the surface lives a creature still largely unknown: the bluntnose sixgill shark. Researchers have recently had the opportunity to film the fish more than 500 meters deep.
The bluntnose sixgill shark (Hexanchus griseus) is a regular on the temperate and tropical seabed. You will find it, with a little luck, at between 200 and 2,300 meters deep. Here silence and darkness reign, but this gigantic fish (up to 8 meters long) seems to fit very well. So much so that it has hardly evolved since the last 200 million years.
Although some specimens have already been studied, the great majority have been studied after being brought up to the surface. This is why we have never had a faithful representation of this shark. To study it with more precision, we must go into the depths of the ocean.
This is what a team of biologists from Florida State University recently undertook. They went to the Bahamas aboard the OceanX Alucia research vessel, and armed with bait, the team plunged into a submarine several hundred meters under the ocean off Cape Eleuthera, hoping to find a shark.
After three fruitless nights, on the fourth night they got a break. The researchers have indeed fallen on several specimens. They also managed to record a big male.
More footage of six-gill at 528 meters from inside the sub last saturday. This sequence was taken by Lee Frey, our multi-talented sub pilot/engineer/inventor who designed the solenoid triggered spear guns for sub-based tagging. Thanks again to the entire OceanX team. Amazing.. pic.twitter.com/hnW4hQLhm7
— Gavin Naylor (@gavinnaylor) July 2, 2019
These very impressive images, filmed more than 500 meters deep, were posted on Twitter by marine biologist Gavin Naylor. The shark featured is a huge female recorded on Saturday, June 29th. Attracted by the bait, it can be seen very clearly under the lights of the submarine.
We can not see it on these images, but unlike its more evolved parents, who have five ears, this shark has the particularity of having kept six, like its ancestors of the Jurassic. Like most other sharks, it hunts live prey but also feeds on carcasses that have fallen to the bottom of the sea. Its life expectancy is estimated to be between 60 and 80 years old.
The researchers are obviously delighted. For these exceptional images, on the one hand, but also because the marking operation is a success. If everything goes as planned, they will be able to follow the movements of this shark day after day, allowing us to better understand its way of life.