Sharks can travel extraordinary distances. One white shark tracked from South Africa reached Western Australia before returning home—a journey of almost 11,000km. School sharks have crossed some 3,000km of the Tasman Sea, between Australia and New Zealand.

Yet, for most migratory shark and ray species found in Australian waters, scientists still know surprisingly little about where they actually go.

A citizen-science analysis has documented 1,524 dead weedy sea dragons and 159 leafy sea dragons during the harmful algal bloom that has affected South Australian waters since early 2025.

The toll extends well beyond sea dragons. More than 1,400 pipefish and around 160 seahorses were also recorded, with at least 13 species from the Syngnathidae family affected. 

Sea dragons appear particularly vulnerable. Their small gill openings can become clogged by microalgae, and their limited swimming ability makes it hard to escape dense patches of a bloom.

One of Australia’s most famous shipwrecks is providing fresh knowledge of the origins of global supply chains nearly four centuries ago.

New research analysing ballast and building stone recovered from the wreck of the Dutch East India Company (VOC) ship Batavia has revealed that the vessel carried stone sourced from several different European quarries. The evidence suggests that Dutch shipbuilders were drawing materials from a wide geographical area, showing a sophisticated international procurement network long before the Industrial Revolution.

The wreck of the iron steamship City of Hobart has been identified off the Gippsland coast in Victoria, Australia, resolving a maritime mystery that endured for more than a century. Technical divers from Southern Ocean Exploration (SOE) confirmed the wreck’s identity after revisiting a site detected during offshore wind-farm seabed surveys.

The discovery followed years of intermittent search efforts by researchers and divers seeking to locate the long-lost vessel.

Scientists say some sites have lost more than 90 percent of their living coral, with the Rowley Shoals—once a dream destination for pristine reef dives—among the hardest hit.

“When you have more than about 75% of corals that have bleached or died, it can be very hard to find any healthy corals.”

^{— Dr James Gilmour, senior researcher, Australian Institute of Marine Science}

Marine archaeologists have confirmed the discovery of the Koning Willem de Tweede, a Dutch merchant ship that sank off the coast of Robe, South Australia, in June 1857. The 800-ton, 140-foot vessel was located approximately 400m offshore in Guichen Bay, submerged at depths between 4 and 6 metres. 

The wreck was found 40 metres deep, approximately 7.8 nautical miles south of Rottnest Island, by divers investigating a sonar anomaly on 1 January 2025.

A historic vessel

Built in 1925 for the Royal Netherlands Navy, K XI was one of the first submarines designed for long-range patrols in the Netherlands East Indies (NEI). During World War II, the vessel was relocated to Fremantle, Australia, where it played a role in Allied submarine operations in the Pacific theatre.