A still from the first video recording of a live giant squid, filmed in December 2006 by Japanese researchers. The first footage of another deep-sea squid, Taningia danae, has revealed that the animal dazzles its prey using flashes of light from specialised cells on its armtips.

Credit: AFP

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PARIS: Huge deep-sea squid use blinding flashes of light from their armtips to disorientate their prey before attacking at speed, Japanese researchers report.

Using a newly-developed underwater high-definition video camera, a team led by Tsunemi Kubodera of the National Science Museum in Tokyo recorded the first live images of Taningia danae, one of the world's largest squid species.

These eight-armed creatures inhabit the ocean to depths of around a thousand metres, and can grow to more than 2.3 metres and weigh 60 kilograms or more.

The video – recorded with assistance from the Japan Broadcasting Corporation and the Ogasawara Whale Watching Association – also reveals that the squid is a speedy swimmer, not a lazy drifter, as was previously thought.

Remains of T. danae are often found in the stomachs of sperm whales, and the squid's flabby flesh led experts to believe that it floated in the water column like a neutrally buoyant scuba diver.

But the new footage shows that - far from being sluggish and neutrally buoyant - T. danae can swim nimbly backwards and forwards by flapping its large muscular triangular fins, and can quickly turn its flexible body.

But the biggest surprise was the team's discovery that the squid can make bright flashes of light from clusters of light-emitting cells called photophores on its armtips. The flashes last about one and a half seconds and are used to dazzle prey before the squid makes an attack.

The light "might act as a blinding flash for prey as well as a means of measuring target distance in a dark, deep-sea environment," the scientists reported in the British journal Proceedings of the Royal Society B.

The squid were filmed around bait rigs lowered to depths of between 240 and 940 metres off Japan's Ogasawara Islands in the northwestern Pacific.

After flashing, the squid attacked its prey, reaching speeds of up to nine kilometres per hour, which is extraordinarily fast given the pressure of water at that depth.

From time to time, the squid emitted long and short glows from its armtips, "suggestive of potential courtship behaviours during mating," said Kubodera.

In September 2005, Kubodera and a colleague, Kyoichi Mori of the Ogasawara Whale Watching Association, reported on the first recording of a live giant squid, one of the strangest and most elusive creatures in the world.

The giant squid, of the genus Architeuthis, is a legend among mariners, the source of tales of tentacled monsters pulling ships beneath the waves to their doom.

It memorably featured in Jules Vernes' 20,000 Leagues Under the Sea, trying to engulf the submarine Nautilus.