The Twofold Shelf Marine Bioregion encompasses the area east of Wilsons Promontory, into New South Wales as far north as Tathra. It extends south to the Kent Group of islands in Bass Strait.


Marine Protected Areas

  • Ninety Mile Beach Marine National Park
  • Beware Reef Marine Sanctuary
  • Point Hicks Marine National Park
  • Cape Howe Marine National Park


Significant areas of Twofold Shelf

  • Ninety Mile Beach
  • Gippsland Lakes
  • Bemm Reef
  • Mallacoota Inlet and Gabo Island

Caption: Crayweed (Phyllospora comosa) is one of the dominant seaweeds found in the Twofold Shelf Marine Bioregion đź“· Nicole Mertens
  • It has an exposed coastline with long sandy beaches broken by rocky headlands and numerous coastal lagoons
  • There is a moderate tidal range of approximately 2 m, and wave energy is variable
  • Ocean water temperatures are influenced by the warmer waters of the East Australian Current that originates in the tropics
  • Reefs are generally dominated by marine animals from warmer waters that occur commonly in southern New South Wales
  • Golden Kelp (Ecklonia radiata) and Crayweed (Phyllospora comosa) are the dominant seaweeds
  • The large Black Sea Urchin (Centrostephanus rodgersii) is common. This animal removes kelp from shallow reefs, creating bare areas known as ‘barrens’

Caption: The sponge gardens at Whaleback Reef, Point Hicks đź“· Jerome Mallefet
  • The exceptionally high diversity of reef-life at Point Hicks including the magnificent sponge gardens at Whaleback Rock
  • Areas of the sandy seafloor off the Ninety Mile Beach have some of the highest levels of diversity of tiny sand animals recorded on earth
  • Gabo Island in eastern Victoria is home to the world’s largest colony of Little Penguins (Eudyptula minor)