Portsea Hole

The Portsea Hole is a depression in the seafloor of Port Phillip near Portsea in Victoria, Australia. The undefined area of the depression, generally assessed at 10 ha, is one of six separate areas that comprise the Port Phillip Heads Marine National Park and is a popular site for divers.

Features
The Portsea Hole is a remnant section of the drowned valley of the Yarra River, descending sharply from the 12 m depth of the surrounding seabed to 32 m, exposing changes in the strata of the limestone sides with depth. It is characterized by diverse and abundant fish assemblages as well as a rich benthic community of marine invertebrates, encrusting algae, sponges and soft corals.

The Portsea Hole in Port Phillip is about 500 m from the Portsea Pier. To the north there is a vertical wall approximately 75 m long. The wall has small overhangs which are home to plenty of marine life, including Blue Devil fish. The Portsea Hole is a popular boat dive site for recreational scuba diving activities.