The ocean is home to some absolute whoppers and some of the largest creatures are also the most elusive. One such giant is the bigfin squid that belongs to the family Magnapinnidae, a group of deep-sea squid with large fins and long, noodly arms and tentacles. It has only been spotted in the flesh on a handful of occasions. Now, new research published in the journal PLOS One details the incredible discovery of five bigfin squid in the Great Australian Bight, the first time they’ve been seen in Australian waters.
Previous reports of these ocean giants have always been of a single individual, so to capture five of these on camera was a big deal for the team from Australia’s national science agency, CSIRO. Though they weren’t spotted all at once, the bigfins have small differences in their appearance, which made it easy for the team to recognize they were five different animals and not just one camera-hungry squid. All five were seen at depths of 2 to 3 kilometers (around 1.5 miles) over a 25-hour period but were within 300 meters (984 feet) of one another, constituting a veritable crowd for an animal that’s never been seen with a party of more than one.
The first-of-its-kind discovery offered a unique opportunity to shine some light on these creatures of the deep, and the team were able to get an accurate reading on their size for the first time. Previous in-situ attempts to measure them have involved using nearby objects of known length, such as the arm of a submersible, but this new research used lasers to get a more accurate picture of their size. The results? The largest individual was over 1.8 meters (almost 6 feet) long with a maximum tentacle length of almost 11 times its body size. The animal was mostly white at the tips of its arms and tentacles but was sporting a mix of brown, orange, and pink hues towards its upper limbs, mantle, and fins. The researchers also spotted a behavior never before observed in squid, as a bigfin adopted a raised arm posture known as the ‘elbow’ pose.
“We filmed the five bigfin squid in depths of 2 to 3 kilometers using a towed camera system and remotely operated vehicles (ROVs),” said marine scientist Deborah Osterhage from CSIRO in an email to IFLScience. “We were doing image-based surveys to find out more about the deep-sea environment in the Great Australian Bight. The first two were seen in the towed camera footage when it was watched back onshore in the video lab. We recognized them as bigfin squid and knew how rare it was to see them, so in the subsequent ROV survey we really kept an eye out for them. We were lucky enough to see three more and were able to watch in real-time on the ship while the ROV filmed them — pretty exciting!
“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 and there is much more to learn about the deep-sea and the incredible animals that live there. So, for bigfin squid we need to wait for more sightings, or more ideally an adult specimen in good condition — which has never been collected before.”