Three young squid caught by marine biologists are the spitting image of their gigantic parents – if nearly 1,000lbs and 50ft smaller

This article is more than 4 years old

This article is more than 4 years old

Marine biologists have captured three young giant squid, Japanese researchers reported, in what would be the first confirmed catch of very young juveniles of the elusive creature.

The young squid, caught off south-western Japan, are replicas of their gigantic parents who live in the deep. Two were caught together; all three weighed less than 1lb and spanned 5-13ins. Adults can reach 50ft and 1,000lbs.

The smallest squid was captured alive, at a depth of 45 metres, leading the researchers to speculate that young squid may drift on ocean currents or inhabit shallow water at night. They “may inhabit and migrate through different depths of the ocean depending on the development stage”, the researchers said.

The researchers said “genetic analysis” supported their identification of the squid as juvenile giants, which was also based on mantles, suckers and other body parts. The squid were caught by various fishermen in 2013, but the researchers published their findings only this week, in the journal Marine Biodiversity Records.

“This is the first time in the world that such young giant squid were found, and it has helped us understand what they are like this early in their life stage,” paper co-author Toshifumi Wada told the Wall Street Journal.

That two of the squid were captured together in the Sea of Japan may indicate that juvenile giant squid travel together, he added, in contrast to the solitary habits of adults.

“It was interesting that they caught several of them together,” Mike Vecchione, a cephalopod expert at the Smithsonian, told the Guardian. “We’ve been looking for a long time and not been finding them.”

The two squid caught together were caught in a purse seine net as, to the biologists’ knowledge, “the first record of a simultaneous capture of paired giant squid”.

The researchers hope that further study of the finding – off Hamada at about 120 meters deep – may provide clues regarding migratory patterns and spawning.

“Although nothing is known of the spawning areas of the giant squid,” they wrote, “the presence of juvenile or small, young individuals should be useful for the presumption of spawning grounds.”

The giant squid’s fame, its tentacles touching Norse mythology, monster sightings by sailors and beach combers and the science fiction of Jules Verne, flows in large part from the animal’s mystery. Although mankind has known of the creature for centuries, no scientist had photographed a living giant squid until 2005, and no one had filmed the creature until 2013.

Tsunemi Kubodera, one of the researchers who managed to first film a living Architeuthis dux, was also a co-author in the juvenile squid report. Steve O’Shea, a marine biologist from New Zealand once dubbed “the squid hunter”, told the Guardian “the gods regularly shine” on his friend.

“I’m really pleased to see someone still publishing research of this nature, finding new and wonderful things in this day and age,” O’Shea said.

“I looked through many thousands of bottles of pickled squid in my time in a search of this very species at this very size. I would have cried for joy had I found it.”

Vecchione, who like O’Shea was not involved in the research, said the finding was exciting for what it may reveal on the young life stages of giant squid.

“People are calling these babies, but they hatch out much, much smaller than this,” Vecchione said.

Giant squid hatch out of tiny eggs and live as “paralarvae” that feed on tiny crustaceans called copepods. O’Shea said he once found specimens that may have been giant squid paralarvae, but the Japanese specimens were “considerably larger” and “look more like the adults” than what he found.

“We know very little about their early life history,” Vecchione said, though he and O’Shea agreed that scientists could try to infer much from remains and the lives of other species.

For instance, Vecchione said that from remains, scientists know that as they grow “giant squid graduate to eating krill and shrimp, and then fish and other squid”.

Adult giant squid live in intermediate depths of the ocean, often among undersea canyons where fish live in abundance and sperm whales dive to hunt.

They may be attracted to bioluminescent light, which the biologist Edith Widder theorizes may be part of an elaborate lure: a fish or jellyfish may start to glow when irritated or threatened, inviting a bigger fish – or squid – to dine on the would-be predator.

“For a big predator it makes sense to be attracted to bioluminescent flashing,” Vecchione said. But he cautioned that for many deep-sea species, scientists were forced to draw conclusions from sketchy details.

One such puzzle is the mating behavior of giant squid, he said. Female squid tissue shows that males apparently inject sperm “like a hypodermic”, Vecchione said. But researchers do not know how that the squids actually fertilize eggs.

Aquariums in Shimane and Kagoshima will display the juvenile squid remains, according to the researchers.