Follow the Fish: Marine Life Could Help Reveal Hidden Shipwrecks

Published 4 hours agoon September 28, 2026

3D seafloor mapping of Althea II shipwreck (red) surrounded by a ring of mysterious holes on the seafloor. Image © CSIRO

Marine life gathering around shipwrecks could provide researchers with an unexpected clue to finding wrecks hidden beneath the ocean.

Scientists aboard Australia’s CSIRO research vessel Investigator made the observation while surveying the wreck of Althea II, a popular dive site lying in around 40 metres of water off Bundaberg, Queensland.

Detailed mapping revealed something unusual: approximately 300 circular holes surrounding the wreck, extending around 100 metres across the otherwise flat seabed. Each depression is typically around eight metres wide and two metres deep.

Underwater camera footage showed the wreck teeming with marine life, including large Goldspotted Rockcod. Researchers believe the holes are likely the result of bioturbation – the movement and mixing of sediment by fish, crustaceans and other animals as they feed, excavate and create shelter.

Remarkably, similar marks have already helped researchers find a lost shipwreck.

During a 2017 search for the SS Macumba, a merchant vessel sunk by Japanese aircraft during the Second World War, researchers spotted mysterious pockmarks near the edge of their search area. Suspecting they could indicate a feature nearby, the team extended its survey – and passed directly over the missing wreck, solving a 74-year-old maritime mystery.

Shipwrecks can become biodiversity hotspots, providing shelter for small fish and crustaceans and attracting larger predators. Scientists now believe the marine communities that develop around them could effectively increase the detectable footprint of a wreck from a relatively small structure to an area hundreds of metres across.

Source: CSIRO Marine National Facility

Jane Morgan

Jane’s lifelong love for the ocean began in childhood and has shaped the course of her life and career. After learning to dive in 1991, she spent much of the '90s teaching scuba and working on marine conservation projects in the Philippines and Borneo. A chance encounter with a film camera on a dive trip to Egypt in 2001 ignited a passion for underwater photography, inspiring her to leave the corporate world and pursue a full-time career in dive travel and photojournalism. Since then, her work has been published in a wide range of national and international magazines, books, and newspapers. She has filmed underwater for the BBC, judged major photography competitions, and received numerous accolades—including the prestigious Plongeur d'Or at the Festival Mondial de l'Image Sous-Marine. In 2009, Jane became a freelance photojournalist, and in 2011 completed a BA (Hons) in Marine and Natural History Photography at Falmouth University, where she now works as a Dive Safety Officer. Based in Cornwall, Jane dives locally year-round and is passionate about showcasing the rich marine life found in UK waters. As a proud ambassador for Dynamic Nord and Fathoms Free, she actively supports marine conservation initiatives and advocates for ocean protection through her storytelling. In her newest role with Scubaverse, Jane combines her love of travel, diving, and storytelling—sharing experiences from around the world to inspire others to explore, protect, and connect with the underwater world.

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