56 Facts About 149 New Deep-Sea Species

By Share a Fact Editorial Team · Published August 28, 2026

The Discovery at a Glance

Researchers documented 1,059 species during surveys around remote seamounts in the central-eastern Indian Ocean.
Of those recorded animals, 149 were identified as species previously unknown to science.
The newly identified animals include black corals, sea worms, sea cucumbers, crustaceans and fish.
The results were published in the journal Deep Sea Research Part II in June 2026 and reported more widely in August.
The expedition explored deep water around Christmas Island and the Cocos (Keeling) Islands, both Australian external territories.
The survey filled a major knowledge gap because earlier biological work near the islands had concentrated on shallow water.
Scientists sampled from 94 metres down to 5,431 metres, spanning coastal depths to the abyssal seafloor.
Twenty-three fish species recorded by the team had never previously been identified in Australian territorial waters.

Christmas Island lies south of Indonesia, while the Cocos (Keeling) Islands sit about 960 kilometres southwest of Christmas Island.
Reaching Christmas Island from Darwin aboard the research vessel took the expedition nearly seven days.
The team mapped 22 seamounts before conducting detailed biological sampling.
A seamount is an underwater mountain that rises at least 1,000 metres above the surrounding seafloor but does not reach the surface.
The surveyed volcanic seamounts are estimated to be between 40 million and 120 million years old.
Some of the underwater mountains extend as much as 70 kilometres across.
Researchers found a caldera at 3,103 metres deep and nicknamed it the Eye of Sauron because its shape resembles an eye.
The Eye of Sauron lies about 282 kilometres from Christmas Island and was mapped rather than biologically sampled.

The work was carried out from CSIRO's research vessel RV Investigator, which was commissioned in 2014.
A four-metre-wide beam trawl collected animals while being towed at roughly walking pace across the seafloor.
The beam trawl was connected to the ship by as much as eight kilometres of wire during the deepest sampling.
A smaller conical net mounted above the main net captured tiny crabs, lobsters and other animals the larger mesh could miss.
A deep-towed camera recorded habitats and animals without requiring a crewed submersible.
Instruments measured temperature, salinity and dissolved oxygen so species records could be matched to their environment.
Environmental DNA samples detected genetic material that organisms had shed into the surrounding water.
Combining physical specimens, imagery, environmental measurements and DNA gave the team several ways to verify what lived at each site.

One newly identified sea cucumber belongs to the deep-sea genus Oneirophanta.
A new greeneye-family fish belongs to the genus Chlorophthalmus, whose name refers to its distinctive green eyes.
The finds include a parasitic barnacle from the genus Rhizolepas.
Black corals were among the newly recognised species collected from the seamount habitats.
The large trawl brought up many jellyfish and worms from the deep seafloor.
The smaller net revealed crustaceans that would otherwise have slipped through the main trawl.
Species communities changed gradually with depth instead of remaining identical from a seamount's base to its summit.
The unexpected variety of fish was one of the results that most surprised scientists commenting on the study.

Deep-sea animals live without sunlight and depend heavily on organic material sinking from productive surface waters.
Water at these depths is cold, food is limited and pressure is many times greater than at sea level.
Seamounts interrupt deep currents and force water to accelerate around their slopes and summits.
Faster flow can deliver more suspended food to corals, sponges and other filter-feeding animals.
An elevated seamount can therefore act as a feeding oasis compared with a flatter stretch of abyssal plain.
Different depths bring different temperature, oxygen and food conditions, helping explain the changing species communities.
The Indian Ocean covers about one-fifth of the world's ocean area.
Around 90 percent of the Indian Ocean is deeper than 1,000 metres, yet much of its deep biodiversity remains poorly surveyed.

The expedition's final trawl recovered roughly 1,000 shark teeth from the Cocos Abyssal Plain.
Researchers nicknamed that collection site the Shark Graveyard.
The teeth span more than 22 million years of shark evolution.
Species represented include great white, mako and tiger sharks.
Fossilised teeth from the extinct giant shark Otodus megalodon were also present.
Shark teeth are replaced repeatedly through life, which helps explain why they are far more common as fossils than complete shark skeletons.
The trawl also recovered polymetallic nodules, including nodules that had formed around some teeth.
These slow-growing mineral-rich nodules contain metals sought for batteries and renewable-energy technologies.

The Australian government approved the surveys before creating the Indian Ocean Territories Marine Parks in 2022.
A species inventory gives marine-park managers a baseline against which future ecological change can be measured.
Formal recognition of a new species requires comparison with existing specimens and scientific descriptions, so discovery continues after a voyage ends.
The 149-species figure may change as taxonomists complete further examination of the collected material.
Deep habitats face pressure from ocean warming, marine heatwaves, pollution, overfishing and proposed seabed mining.
Mining polymetallic nodules could disturb animals and habitats that scientists have only just begun to catalogue.
Long-distance expeditions are costly and technically difficult, which is one reason large areas of the deep Indian Ocean remain unexplored.
The survey shows that mapping an unknown seamount can reveal both living biodiversity and a fossil record stretching millions of years.