Scientists exploring deep underwater canyons off Western Australia have uncovered an unexpectedly rich world of marine life using environmental DNA collected from seawater thousands of meters below the surface.
A new study led by Curtin University has uncovered remarkable biodiversity inside deep underwater canyons off Western Australia’s Nyinggulu (Ningaloo) coast. The discoveries include elusive giant squid and several species that may be previously unknown to science.
The expedition, led by the Western Australian Museum aboard the Schmidt Ocean Institute’s R/V Falkor, explored the Cape Range and Cloates submarine canyons about 1,200 kilometers (745 miles) north of Perth. Researchers collected more than 1,000 samples from depths reaching 4,510 meters (14,797 feet).
Scientists used environmental DNA (eDNA), which is genetic material naturally released by animals into seawater, to identify species living in these deep-ocean environments without directly observing or capturing them.
Giant Squid and Rare Deep-Sea Species Detected
One of the most notable discoveries was evidence of the giant squid (Architeuthis dux) in both the Cape Range and Cloates Canyons. Researchers identified traces of the species in six separate samples. The team also detected deep-diving whales, including the pygmy sperm whale (Kogia breviceps) and Cuvier’s beaked whale (Ziphius cavirostris).
Giant squid can grow longer than a school bus, reaching lengths of 10 to 13 meters (33 to 43 feet) and weights between 150 and 275 kilograms (330 to 606 pounds). They also have the largest eyes in the animal kingdom, measuring up to 30 centimeters (12 inches) across, about the size of a large pizza.
In total, the study identified 226 species across 11 major animal groups, including rare deep-sea fish, squid, marine mammals, cnidarians, and echinoderms.
Researchers also found dozens of species never before recorded in Western Australian waters, including the sleeper shark (Somniosus sp.), faceless cusk eel (Typhlonus nasus), and slender snaggletooth (Rhadinesthes decimus).
A Vastly Undiscovered Ecosystem
Lead author Dr. Georgia Nester conducted the research during her PhD studies at Curtin University and now works at the Minderoo OceanOmics Centre at The University of Western Australia. She said the findings demonstrate how little scientists still know about deep-sea ecosystems around Australia.
“Finding evidence of a giant squid really captures people’s imagination, but it’s just one part of a much bigger picture,” Dr. Nester said.
“We found a large number of species that don’t neatly match anything currently recorded, which doesn’t automatically mean they’re new to science, but it strongly suggests there is a vast amount of deep-sea biodiversity we’re only just beginning to uncover.”
Dr. Lisa Kirkendale, Head of Aquatic Zoology and Curator of Molluscs at the WA Museum, said there had previously been only two records of giant squid in Western Australia, with no sightings or collected specimens for more than 25 years.
“This is the first record of a giant squid detected off Western Australia’s coast using eDNA protocols and the northernmost record of A. dux in the eastern Indian Ocean,” Dr. Kirkendale said.
How Environmental DNA Revealed Hidden Marine Life
Dr. Nester collected water samples from the ocean surface to depths greater than 4 kilometers (2.5 miles). Researchers combined the eDNA results with genetic reference sequences from physical specimens collected by the remotely operated vehicle SuBastian.
Taxonomists identified the collected specimens, which are now stored in the WA Museum’s Collection and Research Facility to support future research.
“The WA Museum contributed expert identification of specimens from the expedition, supporting the development of a local curated genetic reference that strengthened the eDNA analyses,” Dr. Kirkendale said.
According to Dr. Nester, eDNA allows scientists to detect fragile, rare, and fast-moving species that traditional cameras and nets often fail to capture.
“These canyons are incredibly rich ecosystems and, until now, they’ve been largely unexplored because of the difficulty of working at such extreme depths,” Dr. Nester said.
“With eDNA, a single water sample can tell us about hundreds of species at once. That means we can dramatically expand our understanding of deep-water environments in a way that simply hasn’t been possible before.”
The research also showed that marine communities vary significantly by depth, and even neighboring canyons can support very different ecosystems.
Implications for Ocean Conservation
Senior author Associate Professor Zoe Richards from Curtin’s School of Molecular and Life Sciences said eDNA could significantly improve how scientists study and protect the deep ocean.
“Deep-sea ecosystems are vast, remote and expensive to study, yet they face growing pressure from climate change, fishing and resource extraction,” Associate Professor Richards said.
“Environmental DNA gives us a scalable, non-invasive way to build baseline knowledge of what lives there, which is essential for informed management and conservation. You can’t protect what you don’t know exists. The sheer number of discoveries, including megafauna, makes it clear that we still have so much to learn about what marine life lives in the Indian Ocean.”
Dr. Nester said better knowledge of deep-sea biodiversity could help guide marine park planning, evaluate environmental impacts, and monitor ecosystem changes over time.
“By combining eDNA with conventional deep-sea survey techniques, we can build a far more complete picture of biodiversity, revealing species, ecosystems and ecological patterns that would otherwise remain hidden,” she said.
“This kind of information is critical for marine park planning and management, because it gives us a much clearer picture of what species are present and how communities are structured across depth.”
Reference: “Environmental DNA Reveals Diverse and Depth-Stratified Biodiversity in East Indian Ocean Submarine Canyons” by Georgia M. Nester, Nerida G. Wilson, Glenn Moore, Andrew M. Hosie, Rachel Przeslawski, Michael Bunce, Lisa Kirkendale and Zoe Richards, 7 March 2026, Environmental DNA.
DOI: 10.1002/edn3.70261
Fieldwork was supported by the Schmidt Ocean Institute, the Western Australian Museum and the study involved a collaboration between researchers at Curtin University, UWA, The Western Australian Museum, Minderoo OceanOmics Centre at UWA, University of Tasmania and Research Connect Blue.
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