The Bay is a habitat for plants ranging from microscopic floating algae, to sea-grasses, seaweed and mangroves.
Seaweeds are most commonly found on rocky seabeds although unattached seaweed can also be found growing over large areas of the sandy seabed. Huge meadows of seagrass exist in many shallow areas of the Bay, particularly along the north-west coastline.
Underwater seagrass meadows look very similar to grassy environments that you might see on land, and are an important habitat for marine animals.
Mangroves are generally found in sheltered inlets on muddy sediments. These plants live within the intertidal zone, their roots almost entirely submerged at high tide.
Port Phillip is habitat to over 1000 species of marine plants and animals and 500 species of fish.
Rocky shorelines shelter a range of invertebrates including marine snails, starfish, anemones, crabs and worms, as well as sea squirts and shellfish that are commonly found attached to rocks and pilings.
A number of burrowing worms, crustaceans and molluscs, collectively known as infauna because they live under the sand, are found in the soft sediments of the sea floor. Colonies of sea squirts live on top of the sea floor, some species forming colonies that are important attachment points for seaweed.
The Bottlenose dolphin is a resident of the Bay along with the Australian fur seal, which are particularly common on and in the waters surrounding the channel markers off Sorrento. Occasionally, southern right whales have been known to venture into the Bay, the last sighting occurring in August, 1998.
The Bay supports a large number of seabirds and waders, many of which range over large distances and visit the Bay during their migration. Of particular significance is the colony of little penguins at St Kilda Breakwater, populations of Australasian gannets at Popes Eye and white-faced storm-petrels at the South Channel Fort.