Flying sea cucumbers, spiny sea urchins that glow, and giant crabs have been captured by specialised cameras in deep water off Australia's coastline.
The two cameras have revealed previously unseen behaviours, including sea cucumbers — dubbed "headless chicken monsters" — appearing to fly.
The deep-towed camera system plunged nearly 4,000 metres into the waters of the Gascoyne Marine Park in Western Australia, while the baited remote underwater video system (DeepBRUVS) reached 1,000 metres.
DeepBruvs was designed by a Tasmanian engineering and technology team at the CSIRO and has passed its trial stage and is now in operation with updated systems.
The cameras have the ability to capture high-resolution video and photos of the sea floor.
The never-before-seen images will help support better marine research and management.
"We've had amazing footage of sea cucumbers launching themselves off the sea floor as though they are flying through the water in amazing colours and in beautiful focus," CSIRO Chief Scientist Dr John Keesing said.
"You just can't beat being able to see what they look like in their natural environment, alive and in good condition at those depths."
By remotely deploying baits, DeepBRUVS attracts species to the lens that would ordinarily evade other scientific tools like nets.
"It is slightly lighter and more compact and isn't constrained by having a surface line attached to it," CSIRO senior technician Ryan Crossing said.
"We've found things that have only ever been recorded before in other countries, and we've seen species of lobsters and crabs that we have never caught in any of our sampling gear," Dr Keesing said.
"There are at least three new species of shark and a large number of marine invertebrates that have never been seen before."
The baited underwater video can run uninterrupted for up to 36 hours in one deployment, helping scientists understand the behaviours of a range of marine species.
"Because we are leaving the camera for 24 four hours or longer, we've captured things like scavenging sea urchins, which usually take several hours to converge on the bait and then really compete for the bait," Dr Keesing said.
"We've also found a species of sponges that produce extremely long spicules to well over two metres in length, which are the largest ever collected off Western Australia."
'Deep and dark and really important'
Parks Australia, which manages 60 marine parks covering 39 per cent of Australian waters, will use the data collected on RV Investigator to better understand and protect marine life.
"We need to manage these marine parks with research partners so we can understand these places — the more we understand, the better we can manage them," Parks Australia division head Jason Mundy said.
"Every time a voyage goes out into one of our big, deep, remote marine parks, it discovers new things and species, which is really exciting."
Mr Mundy said one example was when a similar survey showed the long-term impacts of human activities like fishing on the Tasman Fracture marine park off south-east Tasmania.
"It's helped to shed light on places that are deep and dark and really important," he said.
