From fish that resemble dumplings to those that stand on their own "stilts" — deep in waters off Australia's coast, scientists are dredging up mysterious creatures.
Over 2,500 kilometres from Perth lie the Cocos (Keeling) Islands, one of Australia's most remote communities, part of the Indian Ocean Territories, which also encompass Christmas Island.
It is here that scientists are completing world-first biodiversity and sea-floor mapping, aboard the CSIRO's RV Investigator.
Life for species that live in waters about 5 kilometres deep is tough — there is little light and scarce food, and staying hidden is favourable.
It is for this reason, Museums Victoria's senior collections manager Dianne Brae, who is on board the ship, said the fish scientists manage to find in these waters are so terrifying and unique.
"They have to make bioluminescence to make lights to attract food, to hide, or camouflage themselves in the deep sea," she said.
"They often have big sensory organs, they often have big mouths with scary teeth in them to make the most of every meal they can."
The team on board Investigator has managed to find all kinds of species in their "treasure hunt".
One favourite amongst researchers is the "tripod fish", a fish with fins that allow it to stand off the sea floor, so it can eat any food that comes its way.
Another is the deep-sea batfish, which resembles a dumpling.
"These are tiny little anglerfish relatives … they've got a tiny little lure that sits in a depression on their snout that they can actually move to attract prey and they essentially walk over the floor on their modified arms and legs."
But one species, in particular, has caused a stir -- the blind cusk eel, which scientists suspect is a new species.
"These fish have really reduced eyes in fact if you see the picture you'll find they're like little golden depressions in the skin. They've got really loose, flabby, gelatinous skin and they're incredibly rare," she said.
The fish are collected using a net, which is dragged across the sea floor for 30 or so minutes before being brought to the surface and sorted through by scientists on the ship.
"Life in the deep sea is so poorly known that it really is a lucky dip," Ms Brae said.
"Sometimes we get giant manganese nodules and fishes and invertebrates mixed in there, sometimes we get mainly fish … we've only got a tiny little net so there are a lot more animals that live down there that we won't collect."
There is also serious work scientists must complete when they are back on shore to figure out exactly what they have managed to find, so the volume of potentially new species could grow as time goes on.
Mapping an 'underwater magic world'
Scientists on board are also doing the important work of producing world-first 3D mapping of the Islands, revealing unique undersea mountain ranges.
Voyage Chief Scientist Tim O'Hara said most of the sea floor to this point was only known from "fuzzy blobs that have just been detected from satellites".
"[Our mapping has] just revealed this whole underwater magic world of canyons and ridges and sediment slumps and old volcanoes," he said.
"Now we're in the south and we're also mapping sea mounts and every one is completely different. Some are flat-topped, some are ridgy and nulled, it's just amazing country."
The images are gathered using a multi-beam sonar.
"It pulses to the bottom and it bounces back to the ship and that allows us to estimate the depth of the sea floor," Dr O'Hara said.
"You can't do it just by looking obviously because we're way on the surface and the sea floor is way below us, so we use sound as a way of discovering exactly what it looks like.
"It also helps people plan for fisheries and for future management to work out where particular fish congregate at different times of the year. It's really important to understand the landscape as a way of understanding the ecology, as a way of understanding the environment of the area."
On the way back from the 12,000-kilometre voyage, scientists will be passing the Muirfield Seamount, which was discovered in 1973 when an English bulk carrier ran into it.
"It's an enormous sea mount coming up from 5 kilometres below the surface in a big cone," Dr O'Hara said.
"We're really excited because no one's actually seen it before, we don't know what's on the top, if it's a big volcano shape or if it's multiple peaks or whatever ... so we're slowly going along the base now and we're going to reveal it in all its glory."
