Our world beneath the waves

Over 85 per cent of the marine plants and animals that live in the waters of southern Australia are found nowhere else on Earth.

Within this unique marine region are the coastal waters of Victoria where seaweed forests, sponge ‘gardens’, seagrass meadows and sandy plains are home to more than 12,000 different types of plants and animals. This fantastic diversity is protected in 13 Marine National Parks (MNP) and 11 smaller Marine Sanctuaries (MS) where all marine life is fully protected. They cover 5.3 per cent of Victoria’s coastal waters.


What is a bioregion?

Bioregions are defined as ‘assemblages of flora, fauna and the supporting geophysical environment contained within distinct but dynamic spatial boundaries’. They can be terrestrial, coastal and marine.

The boundaries of each bioregion are determined by the geophysical environment, major features and organisms that influence, and occur in, the region.

Identifying and understanding the boundaries and functioning of bioregions are essential for ecological management.

Victoria’s marine environment has been classified into six bioregions according to a nationally agreed scheme based on physical and biological attributes.

Caption: Victoria’s marine bioregions


What is a significant area?

Significant marine areas within each marine bioregion contain some distinguishing and unique natural features such as habitats and species as well as various threats to their natural values. Some of the significant areas also have marine national parks and sanctuaries.


Victoria’s marine bioregions and significant areas


The Otway Marine Bioregion

  • Bridgewater Bay
  • Portland Bay and Deen Maar
  • Port Campbell
  • Cape Otway


The Victorian Bays and Inlets Bioregion

  • West Coast Port Phillip Bay
  • Southern Port Phillip Bay and Port Phillip Heads
  • Northern Port Phillip Bay
  • North Arm Westernport
  • Corner Inlet


The Central Victorian Marine Bioregion

  • Apollo Bay to Angelsea
  • Flinders-Honeysuckle-Merricks-Cape Schanck
  • Phillip Island, Summerland Peninsula and Seal Rocks
  • Cape Paterson to Venus Bay


The Flinders Marine Bioregion

  • Wilsons Promontory





The Twofold Shelf Marine Bioregion

  • Ninety Mile Beach
  • Gippsland Lakes
  • Bemm Reef
  • Malacoota inlet and Gabo Island


The Central Bass Strait Marine Bioregion

  • There are no significant areas currently recognised in Bass Strait


Victorian waters are temperate marine zones, characterised by cooler water than the tropics but warmer water than the polar regions. You might say that it is “just right” to support a wide and wonderful variety of habitats, which in turn support diverse marine animals, algae, and plants. The waters of southern Australia have an incredibly high rate of species endemism (that is, species that are unique to a particular location) – it’s estimated that somewhere between 70-90% of all marine life in southern Australian waters do not occur anywhere else in the world.

Click on a habitat below to read more about its structure and function, and discover some of the marine life that you can find there.