Five squids from the Magnapinna genus, known as bigfins for their distinctive flappy fins, were spotted in deep-sea surveys over the course of three years off southern Australia.These cephalopods are usually found thousands of meters under the sea’s surface, in underexplored waters across the globe.To date, however, not a single adult specimen has been captured, and sightings are uncommon, making the newly obtained survey videos a rare window into their mysterious lives.Scientists believe that despite the remoteness of their habitats, these understudied creatures could still be susceptible to the impacts of a changing climate. A sighting of one of the deep ocean’s most mysterious beings, the bigfin squid, in Australian waters for the first time is creating waves among the scientific community’s squid squad. “It seems other-worldly, and although some people find them a bit spooky, I find their coloration delicate, and their flapping fins and trailing arms quite calming to watch,” said Deborah Osterhage, first author of a new paper in PLOS ONE detailing the findings. Surveys over the course of three years captured high-definition video of five individuals from the Magnapinna genus. With their outsized fins, these squids resemble marine flowers moving silkily across the frame. Though lone bigfin squids have been glimpsed over the decades, these rare sightings remain the kind of novelty that makes scientists jump out of their chairs. Bigfin squid. “The most interesting thing is that they saw so many of them so close together. There are published records and several unpublished observations, but I have never heard of anybody coming across more than one at a time,” said Mike Vecchione, a NOAA scientist, curator at Smithsonian National Museum of Natural History and a leading authority on squids. While Osterhage and her team could distinguish the squids they saw in the video as bigfins, they could not ascertain the species. The Magnapinna genus consists of three species: M. atlantica, M. pacifica and M. talismani. However, to identify them from snatches of video captured thousands of meters underwater is extremely difficult. What makes the task nearly impossible is that no adult bigfin squid specimen has ever been captured. These cephalods inhabit waters more than a mile deep: the five spotted on video were at depths of between 2 and 3 kilometers, or about 2 miles down, in what’s known as the ocean’s bathypelagic zone. To capture anything and bring it back alive and well from the sea’s bowels is a herculean task, so at present, scientists are content with catching them on camera. “Little is known of Bigfin Squid, and many other deep-sea cephalopods, largely due to the inaccessibility of their vast yet little explored deep-sea environments, so each sighting contributes more knowledge of these squids,” Osterhage said. The researchers used remotely operated vehicles, or ROVs, and a towed camera in their surveys. The Great Australian Bight, a vast open bay carved off Australia’s southern coast, spans almost 46,000 square kilometers (17,800 square miles). They sighted two of the squids in 2015 on the towed camera and the other three in 2017 during ROV surveys. Observations of Magnapinna sp. (yellow circles) with sighting numbers, and the locations visually surveyed by towed camera (pink triangles) and Remotely Operated Vehicles (blue squares) in the Great Australian Bight (GAB). Image Courtesy of Deborah Osterhage/Great Australian Bight Deepwater Marine Program. During these runs, the scientists used a new way of measuring the squids with paired lasers. The technology is more accurate than trying to determine a target’s size by comparing it to nearby objects, the common way to get estimates. Using this method, they calculated that one of the squid’s arms and tentacles were about 11 times its body length. How the squids use these extensions remains unknown. “Their sticky nature has led some to believe they are used for ‘fishing’ in order to capture food,” Osterhage said. “If this is the case, having long arms and tentacles would certainly give them more surface area to capture food.” The distinctive elbow-like kink in its arms and tentacles is another subject of curiosity. It could be a way to prevent their spaghetti-like tentacles from getting entangled, Vecchione said. The appendages come with microscopic suckers that can land them in sticky situations. Some have been known to get stuck to submersibles.