Fauna
Wilsons Promontory is not only spectacular above the water but beneath the waters of the Wilsons Promontory Marine National Park an astounding diversity of plants and animals, including some that are found nowhere else in Victoria, can be seen. From large marine mammals to microscopic animals that live in the sand, The Prom is an underwater naturalist's paradise. Wilsons Promontory marks the boundary for many animals that prefer the warm waters of eastern Victoria. The last of the currents that flow from New South Wales and Queensland support populations of warm water fish like the Eastern Blue Groper (Achoerodus viridus) that are only rarely seen further west. The Wilsons Promontory area forms the distribution limit for a number of species. For example: - A number of fish species including the Leafy Seadragon (Phycodurus eques), the Barber Perch (Caesiperca rasor), and the Red Velvetfish (Gnathanacanthus goetzeei) have their eastern limits of distribution here. Likewise a number of warmer species such as the Eastern Blue Groper and the Blue-lined goatfish (Upeneichthys lineatus) have their western distribution limit at the Prom.
- The wiry Seanymph Seagrass, Amphibolis antarctica, has its eastern distribution limit on the east side of the Promontory;
- Intertidal molluscs such as the limpet Notoacmea maya and grazing snail Austrocochlea odontis are common in western and central Victoria but absent east of the Promontory; the beautiful Pheasant Snail (Phasianella australis) also has its eastern limit at the Prom.
- A brittle star Ophionthrix spongicola is absent west of the Promontory
- There is a sudden change in the composition of species of some algae including green algae such as Caulerpa spp, and brown algae including Cystophora
Marine Habitats within the park include: - Subtidal rocky reefs covered in a range of kelp and other seaweeds that provide habitat for numerous fish and invertebrate species;
- Seagrass beds in some of the sheltered bays - Three species of seagrass are present: Amphibolis antarctica (eg Waterloo Bay), Heterozostera tasmanica (eg Oberon Bay), and Halophila ovalis (eg Waterloo Bay).
- Sandy beaches
- Intertidal rocky shores on the steep boulders of granite
- Soft sediment areas among the offshore reefs with diverse animal communities eg. at 80m off south east point there are extensive sponge gardens on flat shell rubble.
In deeper areas under ledges or in caves are fascinating sponge 'gardens'. These are dominated by huge sponges, sea-fans, bright orange, blue or grey lace coral colonies, coloured sea tulips and beds of long, slender sea whips. With this deeper water, kelp forest fish species give way to schools of pink Barber Perch and then Butterfly Perch. Boarfish forage amongst the deep crevices and giant octopuses venture out of the rocks at night. A variety of rays and sharks occupy the sandy areas. The offshore islands support several colonies of Australian Fur Seals and many oceanic birds, including little penguins, short tailed shearwaters, fairy prions, silver gulls and Pacific gulls. Kanowna Island is one of the four breeding colonies of Australian for seal in Victoria. Seals have pups in November and December and at this time Great White Sharks frequent waters adjacent to the pupping areas. Wilsons Promontory Marine National Park protects all of these areas and is of national significance in the recovery of White Shark populations, decimated in most of the rest of the country and the world. Butterfly Perch (Caesioperca lepidoptera)
Butterfly Perch form large schools over deepwater reefs and ledges at the Prom. They are opportunistic feeders that take advantage of eddies that swirl the microscopic animal life, the zooplankton, into concentrations. The areas of reef where this occurs are usually covered with colourful sponges and gorgonian corals and with the combination of pink fish, it makes a visual spectacle when diving. At night, Butterfly Perch retreat into rock crevices to sleep. In shallower water, schools of Butterfly Perch are replaced by schools of Barber Perch that are of similar appearance. Gorgonian Coral (Mopsella zimmeri)
Growing to nearly a metre in height in some areas, the branches of the fan-shaped gorgonian corals are a distinctive feature of the deeper walls, caves and underhangs of the Prom. Orange, red or yellow in colour, gorgonians are a colony of thousands of tentacle-fringed polyps. These retract when not trying to sieve the water for microscopic animals. Gorgonian corals grow on an angle to the prevailing surge and currents, allowing them to feed almost continuously. Beyond this their ecology is largely unknown. You might also see animals known as basket stars with their many arms intertwined with the gorgonian's branches. At night and on overcast days, basket stars use the branches of the gorgonian like scaffolding, stretching their long multi-branched arms into the current to catch microscopic animals. Port Jackson Shark (Heterodontus portusjacksoni)
Harmless, docile and gregarious in nature, this seafloor-dwelling shark is commonly seen nestled in groups under rocky ledges around the Prom. At night Port Jackson sharks venture out and explore the reef, their flattened rows of pointed teeth and their strong jaws enabling them to crush reef animals such as marine snails, urchins, and crabs. Often these sharks will regroup in the same crevice as daylight approaches. Each October the females lay between 10 and 16 dark, corkscrew-shaped egg cases that they wedge into ledges with their mouths. You might be lucky enough to find one of these hatched egg cases on the beach. Pheasant Snail (Phasianotrochus eximius)
With its large, elongated conical shell and pretty colouration, the Pheasant Snail, also known as a Painted Lady, is one of Australia's most beautiful marine molluscs. Growing to a length of 4 centimetres, it can be found grazing in the dense algal growths, and is most conspicuous on brown seaweeds. It occurs most commonly on marine plants just below low tide level on sheltered open coasts. Like many snails, Pheasant Snails use their tiny, file-like 'tongue' to rasp tiny algal plants from the surface of the reef and from seaweed fronds. Pheasant Snails are only found in southern Australian waters and are distributed from Geraldton W.A., to the Prom. Geological, Hydrological and Landform Features
The southernmost part of the Australian mainland, Wilsons Promontory consists of rugged granite ranges, sloping headlands, coarse sandy coves and picturesque offshore islands. It is the northern-most exposed link in a chain of granite mountains that continues across Bass Strait and onto eastern Tasmania. These mountains rise above the sea in places as islands. Islands in the Marine National Park include Kanowna Island, Cleft Island, Anser Island and the spectacular Skull Rock, which gains its name from a huge cave on one side giving the impression of a human skull. The coastline adjacent to the marine park consists of smooth walled granite cliffs that plunge abruptly to the sea floor, and sandy beaches, which slope gradually to depths of 30 to 50 metres within 3 km offshore. The granite habitats of the area are unusual along Victoria's coast and include extensive massive boulder reefs with smooth surfaces, reefs of smaller boulders and rubble, and low profile reefs. These granites are gradually broken by the action of waves into smaller particles, which give rise to the beautiful sands of the Proms beaches. Scientists believe it is possible that the limits to the distributional patterns of many marine species in the area are due to dramatic sea level fluctuations over the last 125,000 years (Pleistocene era). During this period vast changes across the globe occurred as ice caps formed and later melted changing sea levels. In the last period of glaciation or Ice Age sea levels were over 100 meters lower than what they are at present. During this time the Prom and the islands to the south including Flinders Island formed a barrier to movement of water through Bass Strait which led to species becoming different either side of the Prom. This is well recorded for certain species of crabs and molluscs.
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