Great South Australian Coastal Upwelling System

During the austral summer, high-pressure systems over the Great Australian Bight cause southeasterly winds to blow over the coasts of Victoria and South Australia.

[1]: 2, 10, 25 [2] Upwelling events occur nearly simultaneously across the three separate centres, appearing within a few days of each other, despite spanning a distance of approximately 800 kilometres (500 mi).

Here, the continental shelf is generally much wider than at the Bonney Coast - up to 100 kilometres (62 mi) wide off the Eyre Peninsula - and water is not drawn directly from the seafloor to the surface.

[2]: 1–3 [6][7] Extensive upwelling of nutrient-rich water makes the GSACUS an important marine hot spot on Australia's southern shelves.

Marine biologist Peter Gill estimates that 100 blue whales visit the Bonney Upwelling area every year, ranging over 18,000 square kilometres (6,900 sq mi) of ocean from Robe, South Australia to Cape Otway in Victoria.

The feeding grounds may extend further northwest, encompassing the rest of the GSACUS, but incomplete whale surveys are insufficient to establish their true range.

[1]: 36  The Convincing Ground massacre, which took place near Portland, Victoria in 1829, arose over a dispute between European whalers and the Gunditjmara people over ownership of a beached whale.

[1]: 27 Today, southern rock lobster (referred to locally as crayfish) and trawling are the most important fishing industries in the Bonney Upwelling.

[1]: ii, 28  whereas the upwelling off the Eyre Peninsula supports a large sardine fishery, operating chiefly out of Port Lincoln, South Australia.