beach - 2026-05-07

Seven Thousand Shoots and Counting: The Race to Rescue Sydney Harbour's Vanishing Seagrass

Scientists and community volunteers are hand-planting thousands of Posidonia australis fragments in Sydney Harbour, with Palm Beach among the collection sites for this landmark restoration effort

Beneath the surface of Sydney Harbour, a quiet crisis has been unfolding for decades. Posidonia australis — a slow-growing, ancient seagrass species found nowhere else on Earth in the same abundance — has been disappearing from the harbour floor at an alarming rate, lost to boat anchors, pollution, and coastal development. Now, a team of scientists and community volunteers is fighting back, one hand-planted shoot at a time.

Beneath the surface of Sydney Harbour, a quiet crisis has been unfolding for decades. Posidonia australis — a slow-growing, ancient seagrass species found nowhere else on Earth in the same abundance — has been disappearing from the harbour floor at an alarming rate, lost to boat anchors, pollution, and coastal development. Now, a team of scientists and community volunteers is fighting back, one hand-planted shoot at a time. Researchers at the Sydney Institute of Marine Science (SIMS) have successfully transplanted more than 7,000 shoots of Posidonia australis across Sydney Harbour in what is believed to be one of the most ambitious seagrass restoration trials ever undertaken in Australia. The project, which has been quietly building momentum over the past two years, is now entering a critical phase — and the Northern Beaches community has a direct role to play. Palm Beach is among the key collection sites used by the SIMS team, where healthy donor fragments of Posidonia australis are carefully harvested before being transported to degraded areas of the harbour for replanting. The process is painstaking: each shoot must be individually anchored to the seafloor using biodegradable...