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The bigfin squid (Magnapinna) is one of the most elusive creatures we know of.
He dwells in the ever dark depths of the ocean and is an extremely rare sight, with only a dozen confirmed spotting in the world.
Now, for the first time, big-finned squids have been seen off the coast of Australia not once, but five times – and each sighting was a different individual. It is not enough to call the region one Magnapinna hotspot, but the new observations have revealed new behaviors, highlighting the importance of capturing images of deep-sea life in its natural habitat.
“These observations, the first in Australian waters, reinforced the hypothesis of a cosmopolitan distribution and indicated a locally clustered distribution with squid found in close spatial and temporal proximity to each other,” the researchers wrote in their report. article.
Bigfin squids are strange and eldritch beasts. Their body looks fairly typical for a squid, albeit with much larger fins than usual. But their arms and tentacles are really peculiar, with surprisingly long filaments, causing the limbs to reach lengths of over 8 meters (26 feet), several times longer than the body of the squid. Held at an angle perpendicular to the body, the limbs also give it a strange “bent” appearance.
Because they live in the bathypelagic zone, between 1000 and 4000 meters deep, it is not easy for us to study these squids. At this depth of the ocean, sunlight never penetrates and the water pressure is overwhelming.
However, remote-controlled vehicles can go where humans are afraid to walk, and over the past two decades sightings have gradually crept in.
It was just such a piece of equipment that marine scientists used to explore the deep waters off the southern coast of Australia. In an area known as the Great Australian Bight, where little was known about deep-sea wildlife, scientists deployed remote-controlled vehicles and a towed camera from the Marine National Facility’s research vessel. Investigator as part of an intensive research program to catalog life far below the waves.
https://www.youtube.com/watch?v=hRWd3oDlUrM
On five occasions, bigfin squid appeared in the images obtained by the instruments.
The towed camera captured two squids, filming them for four seconds each at 2110 and 2178 meters, at one site in November 2015. The two sightings were approximately 12 hours apart.
The ROV spotted three squids at another site in March 2017 at 3002, 3056 and 3060 meters below the surface. Because the ROV is more flexible, it was able to follow the squids, capturing a longer video of each; the longest was just under three minutes. All three observations took place within a 25 hour period.
Morphological measurements with paired lasers suggest that each of the five squid sightings was a separate individual.
Magnapinna filmed at 3,056 meters. (Osterhage et al., PLOS One, 2020)
“These observations represent the first records of Magnapinna squid in Australian waters, and they more than doubled known records from the southern hemisphere, ”the researchers wrote in their article.
Despite this, sightings were rare: the investigation covered more than 350 kilometers of the Great Australian Bight and recorded 75 hours of video. The critters were only seen at these two locations during these two periods.
“All Magnapinna sp. observations in the Great Australian Bight were made in areas of predominantly soft sediment, on lower slope erosion channel terrains and in the upper part of the submarine canyon, ”the researchers wrote.
“Submarine canyons and similar incised features often support high productivity and diversity in the high seas, and these locations may reflect the habitat preference of Magnapinna sp. “
Although the observations were short, they still allowed to observe certain behaviors of the squid. There was, of course, the characteristic “elbow” pose with the tentacles extended outward, then bent at an angle of almost 90 degrees. Previously, this had mostly been seen when the squid was vertical, but the new images showed this pose in a horizontal position.
Because the tentacles seem quite sticky, it could be feeding behavior, waiting for an unfortunate creature to collide with the long limbs like an insect in fly paper, but we still don’t have enough information for it. determine with certainty.
Another behavior observed by the team was the squid holding an arm perpendicular to its body as it moved from a horizontal position to a vertical position. This is similar to the dorsal arm flexion motion seen in a number of squids, but why bigfin squids do so remains a mystery.
In an entirely new behavior, the researchers also saw one of the squids coiling its filaments close to its body. Previously, the only cephalopod seen doing something similar was the hell vampyroteuthis, another bathypelagic creature that uses its filaments for food.
“Although there are obvious differences between the filamentous appendages of hell V. and Magnapinna squid… the coiling behavior may represent an effective biomechanical solution for the retraction of such long and thin filaments, ”the researchers wrote.
These are fascinating and tantalizing things – new information that shows how little we know about these strange, silent creatures and the deep, dark underwater world they inhabit.
The research was published in PLOS One.
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