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.