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Following recent coral bleaching events in March across the world heritage-listed Ningaloo and Great Barrier Reefs as sea surface temperatures were up 4°C above the summer average, technology from Advanced Navigation has helped uncover and digitally map a hidden yet escalating crisis at one of the world's southernmost reefs off the coast of Western Australia.
Advanced Navigation, a Sydney-based global leader in navigation and autonomous systems with its origins in Perth, has collaborated with Fremantle-based O2 Marine to reveal an explicit visual depiction of Hall Bank, which at 32°S is located well beyond the typical latitudinal range for coral reefs.
Using Hydrus, a micro hovering autonomous underwater vehicle (AUV), the teams conducted a detailed survey of the reef, capturing geo-referenced high-resolution imagery and 4K video in parallel that showed severe coral bleaching and fragmentation.
The data gathered from Hydrus was used to generate a 3D digital twin of the Hall Bank seabed. The model revealed a barren seafloor filled with pale, lifeless corals, documenting the shrinking coral formations.
O2 Marine's ambition is to help businesses accelerate efforts in marine environmental assessment and monitoring, marine fauna, and oceanography - a task that requires the use of advanced technology to collect data and insights for knowledge-sharing in a cost-effective way.
"To truly understand the extent of coral bleaching, we need high-resolution, spatially accurate data that captures both the scale and the fine detail of change beneath the surface," says O2 Marine co-managing director Claudio Del Deo.
Advanced Navigation claims the Hall Bank site, regarded as a rare and valuable example of high-latitude reef resilience, was an deal deployment area for Hydrus given its ability to support extensive coral cover in cold, turbid waters makes it a vital natural lab for studying climate adaptation.
Hosting a unique mix of tropical, subtropical, and temperate coral species, the site offers critical insights into species range shifts and reef development under changing ocean condition
"Unlike traditional underwater vehicles, Hydrus’s compact design, fleet deployability, and ability to gather professional grade data allow us to monitor reefs at a scale and frequency previously unattainable," adds Del Deo.
"This level of detail is essential for informing conservation strategies and building the baseline needed for long-term reef recovery.
"As we expand our conservation efforts globally, Hydrus is proving to be an indispensable part of our toolkit, enabling actionable insights that will guide both immediate responses and future restoration."
The mission involved the simultaneous deployment of three Hydrus units, each executing coordinated transects and lawnmower survey patterns across different sections of the reef.
This approach enabled comprehensive spatial coverage, ensuring overlapping, high-resolution data capture across the site. By flying precise, parallel tracks, Hydrus was able to systematically map the reef’s structure and condition, capturing the fine-scale changes in coral health that are often missed by traditional survey methods.
Advanced Navigation senior AI engineer Alec McGregor says collecting high-quality ocean data has traditionally been slow, costly, and resource-intensive, where sending divers or ROVs below 50 metres in depth can run into tens or even hundreds and thousands of dollars.
"That simply doesn’t scale, especially when time-sensitive data is needed across large or remote areas," McGregor says.
"Hydrus changes the equation. At just 7kg, it can be deployed by a single person, without the need for support vessels or complex logistics. This mission is a powerful example of what’s possible when cutting-edge robotics meets urgent environmental challenges.
"Hydrus puts critical data into the hands of scientists and marine operators faster, more safely, and more affordably - enabling smarter, more timely decisions for conservation and climate adaptation."
Founded by Australia's Top 100 Young Entrepreneurs listers Xavier Orr and Chris Shaw, based on the former's university thesis on artificial intelligence applications for inertial navigation, Advanced Navigation has developed a wide range of drones, sensors and systems that can be applied to not just deep sea exploration but also space, defence, mining, agriculture and geospatial mapping.
In 2023 the group unveiled its 5.5ha subsea drone and robotics facility in Perth where it produces the fully autonomous submersible Hydrus drones.
As only 26.1 per cent of the ocean floor has been explored, Advanced Navigation and its Hydrus technology has the potential to unlock the ocean’s mystery and open it up for further scientific discovery.
By working with partners to map the ocean floor, the company is appealing to the goals of the Seabed 2030 initiative and the overarching United Nations “Ocean Decade” development plan.
The latest mission builds on Hydrus’s growing track record of underwater discovery and documentation - from coral reefs to shipwrecks.
In 2024, Hydrus spotted a 64-metre shipwreck - more than twice the size of a blue whale - scattered across the seafloor in the Indian Ocean. Together with Curtin University HIVE, Advanced Navigation was able to rebuild a high-resolution replica of the wreck using the data gathered by Hydrus.
The model now sits with the Western Australian Museum’s public archive, and can be seen in life-size form at the Curtin University HIVE on their immersive Cylinder display.
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