The deep sea is vast and mysterious. It makes up approximately two-thirds of the planet. Yet, as of May 2025, only 0.001 percent had been seen with the human eye. Now, thanks to efforts led by researchers at Curtin University and the Western Australian Museum, a little more of the deep ocean has been explored.
An expedition to the deep Cape Range and Cloates submarine canyons, near Australia’s Nyinggulu (Ningaloo) coast and approximately 745 miles (1,200 kilometers) north of Perth, revealed remarkably diverse ecosystems, featuring giant squids (Architeuthis dux), pygmy sperm whales (Kogia breviceps), and other species that may be entirely new to science.
“Finding evidence of a giant squid really captures people’s imagination, but it’s just one part of a much bigger picture,” lead author Georgia Nester said in a statement.
“These canyons are incredibly rich ecosystems and, until now, they’ve been largely unexplored because of the difficulty of working at such extreme depths,” added Nester, who was a PhD student at Curtin University at the time of the research and is now at the University of Western Australia’s Minderoo OceanOmics Centre.
The findings have been described in Environmental DNA.
Read More: 8,000 Suggestions Later, a Newly Discovered Deep-Sea Species Gets Its Name
What Is eDNA, and How Is It Captured
Showing that you don’t need to physically observe an animal to detect its presence, the researchers analyzed environmental DNA (or eDNA) in seawater. eDNA is genetic material that animals naturally shed, whether through skin, fluids, or excrement, and traces of it can be found in their surroundings.
“With eDNA, a single water sample can tell us about hundreds of species at once,” said Nester. “That means we can dramatically expand our understanding of deep‑water environments in a way that simply hasn’t been possible before.”
eDNA also has the added benefit of capturing the presence of rare species and fast-moving animals that cameras and nets might miss, the researchers explained.
Giant Squids, Pygmy Whales, And Species That May Be New To Science
During the mission, the team collected 178 ten-liter samples from depths of up to about 14,800 feet (4,510 meters). Collecting samples at five depths, from the surface to the seafloor, enabled the team to capture a snapshot of the ecosystems at different levels of the ocean and between the two canyons.
From samples, the team found evidence of more than 220 species spanning 126 families and 11 animal groups, from marine mammals to deep-sea fish. Genetic reference sequences collected from physical specimens were used to support the eDNA analysis.
One of the most exciting discoveries was eDNA from a giant squid, a creature that rivals a bus in terms of length (33 to 43 feet, or 10 to 13 meters). The species has been known to visit the waters of Western Australia, but there are just two sightings on record, and it has been over 25 years since the last was documented.
The team also found traces belonging to various migratory mammal species. This included the pygmy sperm whale and Cuvier’s beaked whale (Ziphius cavirostris), whose presence in the canyons coincided with bountiful supplies of prey, including squid and fish.
The researchers count a total of 83 genera or species that are thought to be new to science or to Western Australia. Among these was the sleeper shark (Somniosus sp), named after its sluggish pace, the faceless cusk eel (Typhlonus nasus), and the monstrous-looking slender snaggletooth (Rhadinesthes decimus).
A Novel Approach To Deep-Sea Exploration
There are challenges to using eDNA. There is currently a limited amount of reference data to draw upon, and present technology does not enable researchers to determine the life stage of the organisms from which they have collected eDNA. Still, the researchers point to its value as a non-invasive approach to deep-sea exploration.
“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,” Zoe Richards, an Associate Professor from Curtin’s School of Molecular and Life Sciences, explained in a statement.
“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.”
Read More: 99.999 Percent of the Deep Ocean Is Unexplored — Its Secrets Are Key to Understanding Our Planet
Article Sources
Our writers at Discovermagazine.com use peer-reviewed studies and high-quality sources for our articles, and our editors review for scientific accuracy and editorial standards. Review the sources used below for this article:
- This article references information from a study published in Science Advances: How little we’ve seen: A visual coverage estimate of the deep seafloor
- This article references information from a study published in Environmental DNA: Environmental DNA Reveals Diverse and Depth-Stratified Biodiversity in East Indian Ocean Submarine Canyons
