Wednesday September 23, 2026
Phys —
In September 2026, 20 Australian university students departed Brisbane for Fiji aboard the CSIRO research vessel (RV) Investigator on a CAPSTAN sea training voyage. While in coastal waters off Queensland, the students were involved in several shipwreck surveys that led to an intriguing observation: A shipwreck surrounded by mysterious holes on the seafloor. For some aboard, this wasn’t the first time they’d seen such a thing.
The mystery of the circles
The CAPSTAN team was mapping the wreck of Althea II, a popular dive wreck lying in 40 meters (131 feet) of water off Bundaberg, Queensland, when they made the discovery.
Lara Picton, an honors student studying geology at the Queensland University of Technology, described what they saw.
“It was really exciting to watch as we mapped the site in detail. What initially looked like a few depressions in the surface turned out to be far more widespread,” Picton said.
“The entire wreck is surrounded by an almost perfect circle of holes in the seabed, each typically 8 meters (26 feet) in diameter and 2 meters (7 feet) deep. We identified around 300 holes, and they extend approximately 100 meters (328 feet) from the wreck in all directions and are the only features on an otherwise flat seafloor.”