Port Phillip Bay

A precious asset

Port Phillip Bay is arguably the most important environmental, social and economic asset in the region; perhaps in all of Victoria. Its ecological services – climate control, boating, fishing, swimming, transport, effluent and stormwater treatment – are irreplaceable. The Bay is central to our whole region’s identity, culture and economy.

The people of the Kulin nation lived for 30,000 years on the grassy plain and woodlands where the Bay is today. Between 8,000 and 10,000 years ago, the ocean had covered the land bridge to Tasmania but the entrance to the Yarra plain was blocked with sand and silt. The waters of Bass Strait finally penetrated the barrier and Aboriginal oral histories describe the ocean’s dramatic creation of the Bay. First Peoples’ relationships with the Bay’s coastal and marine environments are recorded and preserved in the Bay’s hundreds of coastal cultural sites.

Port Phillip Bay is a large, shallow bay of 1,930 square kilometres. Nearly half the bay is less than eight metres deep and 24 metres marks its deepest point. Basalt rocky reefs formed from volcanic lava flows characterise the bay’s north-western inshore waters. Its western inlets, Corio Bay and Swan Bay, comprise shallow, exposed mangrove coastal saltmarsh, seagrass and tidal flats. This mosaic of freshwater and marine wetlands and the low-lying Mud Islands inside the Bay’s southern entrance comprise a wetland complex of international significance – the 22,650 hectare Port Phillip Bay (Western Shoreline) and Bellarine Peninsula Ramsar Site. 

The journey across the Bay’s southern entrance on the Sorrento-Queenscliff ferry is one of the region’s great pleasures. The ferry crosses a wild environment of sea, sky and land between Bay and ocean. Marine creatures and birds are abundant here where 660 cubic kilometres of swirling tidal waters enter and leave the bay every year through the mile-wide ‘Rip’.

The Bays’ animal life includes unique species of seagrass, hundreds of fish species, molluscs, crustaceans, bristle worms, jellyfish, corals, sponges and seaweeds, making it one of Australia’s most diverse marine environments. 

The Bay is Victoria’s biggest recreational fishery and its 135 beaches are part of life for many of Melbourne’s 5 million residents. They support recreations from swimming, snorkelling and scuba diving to fishing, sailing, motor boating kite-surfing ….. or just walking along its scenic edges.

At the other extreme, Australia’s busiest port, heavy industry, transport infrastructure and the City of Melbourne’s business district have transformed forever the land and waters of the Yarra estuary at the Bay’s most northern extent. 

Port Philip Bay has changed a lot since Matthew Flinders first charted it during April and May in 1802. Five million people now live across the Bay’s drainage catchments and in Victoria’s two largest cities: Melbourne and Geelong. Despite this, the Bay’s water quality, biodiversity and amenity values remain in extraordinarily good condition. The Bay is a priceless inheritance.