Posidonia australis

Posidonia australis (or Posidonia for short) is a species of seagrass that occurs in the southern half of Australia. In NSW, it can be found in 17 estuaries, from Wallis Lake to Twofold Bay near the New South Wales/Victorian border.

Six locations within NSW (Lake Macquarie, Brisbane Waters, Pittwater, Sydney Harbour, Botany Bay and Port Hacking) have suffered significant population decline and have been listed as endangered populations.

Below are maps of the endangered populations as at June 2021. Please note: These maps do not indicate entire species distributions, and there may be errors or omissions. To help us improve the accuracy of the species distribution maps, please report any sightings of Posidonia australis with photos to confirm their identification, using the online reporting form

To view the most up to date distribution maps for Posidonia across the State, visit the Fisheries NSW Spatial Dataset Portal and use the "Estuarine Macrophytes" layer.

For more information about the species, visit Posidonia australis.

Posidonia australis endangered population maps

All of NSW

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Lake Macquarie

Brisbane Waters


Sydney Harbour

Botany Bay and Port Hacking