What is the Bass Strait?

Bass Strait is the body of water between Victoria and Tasmania, separating mainland Australia from its only island state. It is about 240 kilometres wide at its narrowest point, between Wilsons Promontory in Victoria and Cape Frankland on Flinders Island, and stretches around 500 kilometres east to west between the Pacific Ocean and the Indian Ocean.

The strait is generally regarded as part of the Tasman Sea (and therefore the Pacific) on its east, and the Southern Ocean on its west. It is relatively shallow, with depths typically below 80 metres, because it sits on the Bassian Plain, dry land during ice age low sea levels until about 10,000 years ago. Aboriginal peoples crossed regularly between the mainland and Tasmania during this period, before rising seas isolated the island and its inhabitants.

Bass Strait is named after surgeon and explorer George Bass, who along with Matthew Flinders proved in 1798 that Tasmania was an island by sailing around it in a small whaleboat. The strait's many islands include King Island, Flinders Island, the Furneaux Group, and dozens of smaller islands that became refuges for Tasmanian Aboriginal communities, sealers, and lighthouse keepers in the 19th century.

Bass Strait is famous for being one of the most dangerous stretches of water in the world for shipping. The Sydney to Hobart Yacht Race crosses it every Boxing Day; the 1998 race saw a deep low-pressure system kill six sailors and sink five yachts. The Spirit of Tasmania ferries operate daily between Geelong and Devonport. The strait is also a major source of energy: the Gippsland Basin oil and gas fields lie offshore, and proposed offshore wind developments off Gippsland and northern Tasmania would generate large amounts of electricity for the National Electricity Market.