With its proximity to Victoria's largest city the southern end of the Bay has high visitor usage throughout the year with a huge peak over the summer months. The southern Bay is Melbourne's summer playground and many of the areas within Port Phillip Heads Marine National Park are popular for a range of recreational pursuits from snorkelling and SCUBA diving through to passive recreation on the beach.

Habitat types found within the park include seagrass beds, sheltered intertidal mudflats, intertidal sandy beaches and rocky shores, subtidal soft substrata and rocky reefs, as well as the open water environment. The diversity and abundance of marine flora and fauna in this region are greater than many comparable habitats elsewhere in the world. The park is located in an area renowned for its diversity of migratory wader birds and includes a number of sites listed under a number of treaties to protect migratory bird habitat including International Convention on Wetlands of International Importance (the Ramsar Convention).

The high diversity of marine life around the mouth of Port Phillip is due to the wide range of habitats in the area and its central Victorian location. The area marks the end of the range for some animals and plants that prefer the cold waters of western Victoria, but it also supports warmth-loving species from eastern Australia that can survive in the bay's relatively calm, shallow waters. A high proportion of Victorian species of marine flora and fauna are represented in the Port Phillip Head's region. As an example the area supports about 10 per cent of all of Australia's feathery stinging animals known as known hydroids.

There are a number of significant sites adjacent to the Marine National Park where the remains of shellfish and other animals are found in large numbers, in what are referred to as shell middens. These remains show us clearly that the native peoples of this area used the marine environment extensively as a source of food. Midden sites are all protected as they provide us with an important record of he rich cultural history of indigenous Victorians and the coast.

In early European settlement, Port Phillip Heads was the major access point to the important grazing lands of the early colony and later to the rich goldfields of central Victoria. As a consequence a vast number of ships from other parts of the world plied their way through Port Philip Heads, some of which came to grief on the hidden reefs and the narrow entrance to the Bay. A number of the wrecks that occurred in this area are now found within the Port Phillip Heads Marine National Park. These include the Holyhead, George Roper and Conside on the Lonsdale Reef.

The Eliza Ramsden near Point Nepean and the William Salthouse, an important wreck near Popes Eye, lie near the park.

The southern Bay was also an area of concern to the emerging colony as a potential route for invasion by foreign powers expanding their influence in the region in the latter half of the 19th century. Funded largely by gold, Melbournians paid for the construction of a number of forts, some of which are still used by the Department of Defence. Within the Marine National Park, Popes Eye was established as the base of a fortress that was never completed. Alongside the artificial island called South Channel Fort, the extensive fortifications at both Point Nepean and Queenscliff, and a fourth fort built on Swan Island, Popes Eye was intended to protect the entrance to the Bay, although by the time the other forts were completed, it was made obsolete by the range of guns from the other locations. The rocks placed on the sand bar at Popes Eye were soon colonised by kelp and many other plants and animals, and today the site is considered one of the most important dive and snorkelling sites in the Bay.

Aboriginal Traditional Owners

Parks Victoria acknowledges the Aboriginal Traditional Owners of Victoria - including its parks and reserves. Through their cultural traditions, Aboriginal people maintain their connection to their ancestral lands and waters.
Further information is available from Aboriginal Affairs Victoria AAV and Native Title Services Victoria

The Swan Bay component of the Port Phillip Heads Marine National Park incorporates Swan Bay to the eastern shoreline of Swan Island, Rabbit Island and Duck Island excluding the shipping channel to the Swan Bay Jetty.

The natural values of Swan Bay are of regional, national and international significance. The expanse of subtidal seagrass beds is a major nursery habitat for many species of fish, some of which have commercial value. The intertidal mudflats and surrounding fringe of saltmarsh support large numbers of waderbirds including many that migrate from the Northern Hemisphere during summer months. The entire ecosystem is one of the most significant in Port Phillip because of its high ecological values.

The Swan Bay component of the Port Phillip Heads Marine National Park contains the best representative sample of seagrass beds within the park. Two species (Heterozostera tasmanica, Zostera muelleri) occur here in high densities, their distributions dependent on water depth and exposure at low tide. Heterozostera tasmanica or Eel Grass is the dominant species in the deeper channels but is replaced by Zostera muelleri or Swan Grass in the intertidal areas.

The seagrass habitat acts as an important feeding area and nursery ground for numerous fish species including leather jackets, flounder, King George Whiting, Black Bream, garfish and flathead. Forty-four fish species have been recorded in Swan Bay. The importance of Swan Bay as a fish nursery area has long been recognised by Queenscliff fishermen and was protected unofficially for nearly 100 years, before being officially protected under legislation from net fishers in 1970.

In addition, the seagrass habitat is important for black swans, which feed on the seagrass, as well as providing resting and breeding ground for spoonbills, cormorants and egrets. The area is also part of the Port Phillip Bay (Western Shoreline) and Bellarine Peninsula Ramsar site and is used by species listed in international agreements such as the Japan - Australia Migratory Birds Agreement (JAMBA) and the China Australia Migratory Birds Agreement (CAMBA) for the protection of migratory birds. The rare and endangered Orange-Bellied Parrot uses the saltmarshes fringing Swan Bay as a winter refuge and feeding ground.

Mud Islands (Great Sands) component

The Mud Islands component of the Port Phillip Heads Marine National Park is located in the southeastern part of Port Phillip approximately 6 km NE of Portsea. The Mud Islands are an exposed section of the Great Sands, the most extensive sandbank in the Bay, which is continually changing in shape due to storms and sand movement.

The Mud Islands are listed as part of the Port Phillip Bay (Western Shoreline) and Bellarine Peninsula Ramsar site as well as being listed on the Register of the National Estate. The fine sand and muddy sediments exposed between tides within the Mud Islands component of the Marine National Park provide excellent habitat for many birds, including endangered and long distance migratory species. Some 70 species of birds have been recorded on the islands. Vegetation on the low-lying islands consists of saltmarsh and dune shrubland surrounding a sheltered lagoon.

The Mud Islands support a distinctive community of animals that live in the sand. This is an important habitat for numerous invertebrate species, including small crustaceans and segmented worms. These invertebrates provide an important source of food for many fish and birds. Dense seagrass beds, growing over the sand, and mudflats provide vital breeding, foraging and nursery areas for many fish such as King George Whiting. These sandy soft sediments also provide habitat for scallops, mussels, oysters and many bottom dwelling fish. Many bottom dwelling fish species including yank, sand flathead and snapper also rely on animals that live in the soft sediment habitat for food.

Flounder and other fish flourish in the shallow sandy habitats and a number of shark species use these areas for basking. During summer months, Bronze Whaler Sharks also use the warm waters around Mud Islands as an area in which to give birth to their young.

In addition, the microfauna of the sands and mud within this and other areas of the bay are important in maintaining water quality within the whole of the Bays waters. The denitrification processes occurring in the soft sediments within the bay are primarily responsible for removing nitrates from the water preventing massive algal blooms. Sediments also act as sinks for heavy metals and other toxic substances.

Point Lonsdale component

Located between Queenscliff and the western side of the Port Phillip entrance, the Point Lonsdale component of the Port Phillip Heads Marine National Park includes very good examples of the diverse physical and biological features of the area, such as spectacular deep water scenery comprising cliffs, caverns, rocky reef walls, sponge gardens and kelp beds.

Many of the rocks that make up this reefs as well as rocks and cliffs above the water are made of ancient dune limestone or calcarenite. This readily weathered rock is made of sand grains that have been cemented together by the high amounts of calcium carbonate derived from shells which dissolve slowly I rainwater and percolate down through the sand.

The Rip side of Point Lonsdale contains an extensive intertidal rocky platform covered with algae such as Neptune's Necklace, and has a number of larger rockpools suitable for snorkelling. The Point Lonsdale intertidal platform has the highest recorded invertebrate diversity of any calcarenite reef in Victoria.

The reefs offshore from Point Lonsdale provide spectacular underwater terrain with ledges, rock outcrops and bommies, and beds of bull kelp (Durvillea potatorum) on sections exposed to large waves. Fishermen seeking an easier entrance to the bay through the Rip in their small fishing boats blasted a channel out of the Lonsdale reef. The channel between the main rock platform and the outer reef is around 20 metres wide and 2- 4metres deep and contains a small forest of Giant Kelp (Macrocystis angustifolia), a species which is showing signs of decline along the south east coast of Australia. This kelp occurs only sporadically on the Victorian coast and is of interest due to its ability to form complex forest like habitats and also its rapid growth during winter and spring. (A closely related species grows at more that 30cm each day!!). Its grows to over 10 metres in height and its upper canopy provides habitat for a range of fish and invertebrate communities.

Additional features of the area protected by the Marine National Park include:

The Lonsdale Wall: The Wall is a series of ledges that mark the edge of the historical course of the Yarra River. The wall drops down a series of ledges from 15 to 90 metres depth, extending horizontally for about a kilometre. The vertical walls, sheltered caves, ledges and overhangs and their associated communities of colourful sponges, fish and encrusting algae provide spectacular scenery and are popular dive sites. Kelps such as leather kelp (Ecklonia radiata) cover the tops of the rocks to depths of 15 to 20 metres, with animal communities dominating at greater depths. Species include an array of sponges, soft corals, gorgonians, hydroids, jewel anemones and sea tulips. The species diversity in this area is very high, including more than 43 species of fish.

The Kelp Beds: Areas with reefs that previously supported Giant Kelp forests are now dominated by leather kelp. These kelps grow attached to shallow rocky reefs and provides shelter for communities of algae, fish, encrusting sponges, and numerous seastars and sea urchins.

The Sponge Gardens: This area containing a high diversity of sponges and other filter feeding invertebrates in a variety of colours, shapes and forms. Being in the main flow of current through the Rip, these animals are able to extract plankton from the water that passes by. The area derives its name from the spectacular and diverse sponges, branching soft corals, stalked ascidians and carpets of colourful anemones.

The Point Nepean component

The Point Nepean component of the Marine National Park extends around Point Nepean on the eastern side of the entrance to Port Phillip Bay. This component contains extensive shallow reefs up to seven metres in depth covered in kelp and supports a variety of marine life including Victoria's marine state emblem the Weedy Seadragon, seahorses, cuttlefish and numerous algal and invertebrate species.

The Portsea Hole component

Portsea hole is a depression within the bed of the old Yarra River that has flowed through this area during periods of glaciation and lower sea levels. The area is popular with divers and reaches depths of up to 30 metres. Portsea Hole acts as a shelter for a variety of fish and other reef species and the stratification of marine life on the wall provides special qualities as a dive site. It is one of the most popular deeper recreational dive sites in the bay.

The Popes Eye component

The Popes Eye component of the Marine National Park is located approximately 5 km north east of Portsea. Popes Eye is an artificial environment made of bluestone boulders that have been laid in a semi-circular ring which rise approximately 2.5 metres above the surface at low tide. Originally intended to become one of the fortresses guarding the entrance to Port Phillip but never completed, this structure provides a safe anchorage for pleasure craft and the substrate for a rich community of animals and plants that attach to the rocks and associated fish fauna. Inside the ring water depth is only around 1.5m but outside the water drops to a depth around 10m.

On the tops of the rocks are extensive beds of brown kelps including both Giant Kelp and also Leathery Kelp. These species create a forest like environment. Beneath the kelp a vast array of colourful encrusting algae and sedentary organisms such as molluscs of many types, seastars, feather stars, sea urchins, sponges, sea squirts and soft corals adorn the rocks, making it in some respects, an artificial microcosm of the Heads reef environment.

The site is an important breeding site for Australasian Gannets which nest on the platform and rocks above the water, one of the few known sites where Gannets breed on a human made structure in the world. Australian Fur Seals are often seen in the area. Because of its unique shape and protection from tidal currents Popes Eye is one of the most accessible snorkelling and dive sites in the Bay with many people learning to SCUBA dive having this site as there first open water dive. Popes Eye has also been the only fully protected marine environment within Port Philip for the last twenty years and as a consequence there are large numbers of animals present, particularly fish.

Creature Features

Western Blue Devilfish (Paraplesiops meleagris)
Against the backdrop of the bright reds, oranges, yellows and whites of Port Phillip Head's sponge gardens, the vivid sapphire body and iridescent blue spots of the pouting Blue Devilfish is stunning. A favourite with scuba divers, this inquisitive fish rarely ventures beyond its home ledge, crevice or small cave. It is believed that the male guards the eggs that are laid by the female well back in the crevice. Western Blue Devilfish grow to around 30 centimetres in length and are found at depths between 10 and 45 metres. The population of Blue Devilfish at Port Phillip Heads is thought to be the largest in Victoria and the fish is near the eastern extent of its range here.

Verco's Nudibranch (Tambja verconis)
Verco's Nudibranch is just one of the 400 species of nudibranchs found in Australian waters. The name of the group means 'bare gills' and Verco's Nudibranch displays these as feathery plumes on its back. The animal's striking colouration signals its distasteful characteristics to fish - acidic defence glands in the skin making it unpalatable or even poisonous. Verco's Nudibranch preys almost exclusively upon a bushy, green colony of animals known as the bryozoan Bugula dentata. If you look closely near this bryozoan, you can sometimes find the nudibranch's orange eggs in their girdle of jelly. Verco's Nudibranch was named after the prominent South Australian marine naturalist and surgeon, Dr Joseph Verco. They reach 13 centimetres in length and live at depths between two and 36 metres.

• enjoy the marine environment without removing the plants and animals
• minimise your impact while diving and snorkelling by:
  • being careful to avoid damage to marine life caused by fins
  • developing good skills in buoyancy control
  • securing all gauges and pressure hoses to avoid snagging them on objects
• take any rubbish home with you - do not dump rubbish into the sea
• avoid stressing marine life by not chasing or grabbing free-swimming animals
• exercise great care if approached by large marine animals (including birds) & avoid blocking their paths if moving
• take care where you anchor your boat (anchor in sand, rubble or mud, avoiding sensitive areas, and use mooring buoys where provided)
• do not pollute the water with sewage - ensure that if your vessel has an onboard toilet that it has an approved sewage holding facility and that sewage is disposed of appropriately on land
• take the time to learn more about Victoria's marine animals and plants and the habitats they depend upon
  

SCUBA diving is a potentially high risk activity and should only be undertaken by appropraitely qualified people that have completed recognised training and certification. Victoria?s cool water environments can be extremely challenging to those used to diving in warmer waters so ensure that local knowledge is sought before undertaking a dive in a new location. Dive charter operators can provide some of the best advice on diving in Victoria.

• Arthurs Seat State Park
• Barwon Bluff Marine Sanctuary
• Harold Holt Marine Reserve
• Mornington Peninsula National Park