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Scientists say they have recorded multiple sightings of elusive bigfin squid in Australian waters for the first time.
The researchers, led by CSIRO, recorded cephalopods in the deep waters of the Great Australian Bight on two separate trips.
Bigfin squid – or Magnapinna – are known for their long arms and tentacles and can measure up to seven meters in length. They lie miles below the ocean’s surface and there have only been a dozen confirmed sightings of animals in the world.
The scientists embarked on two trips, the first in 2015, followed by a second in 2017. After processing hundreds of hours of camera footage, their results have now been published in the journal Plos One.
The scientists used cameras at depths between 946 and 3258 m. On the first trip, they used a towed camera system that captured two sightings of the animals.
On the second trip, they used remote-controlled vehicles that detected three other Bigfin squids.
Deborah Osterhage, who was one of the CSIRO scientists on both trips, said the researchers were confident that each of the five sightings were separate individuals due to differences in their appearance, including their color.
In addition to marking the first time animals have been recorded in Australian waters, it doubles known records in the Southern Hemisphere.
Osterhage said the findings were significant because animals are seen so rarely and much remains to be understood about them.
“They’re a pretty peculiar squid, so when you see them, you know you’ve really seen them and the fact that they’re not seen very often is what makes them so attractive,” she said. “They seem almost otherworldly.”
Osterhage said scientists had previously used a nearby object of a known size to estimate the size of the Bigfin squid.
The research team was this time able to project lasers onto the body of one of the squid they recorded to determine an accurate measurement, which reached 1.8 meters.
“That was mostly made up of arms and tentacles. The body was only about six inches, “he said.
Knowledge of deep-sea cephalopods has been limited in part because specimens collected in the past were of animals that had been injured and killed by deep-sea trawl nets.
In their article, the scientists claim that underwater imagery revolutionized the study of elusive fauna such as the giant squid because it allowed researchers to observe live animals in their habitat.
The two voyages covered a large area but the recorded squid were all spotted in places close to each other. Osterhage said this was something scientists would like to explore further.
“Normally, when you find animals clustered close together, it indicates something about their ecology,” he said.
“It could be that they have a specific habitat that they like or is related to reproduction. If we find they are in a similar habitat, this would give us clues as to why we are seeing this pattern. “
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