Our blueys are facing a new threat

340,000 blue whales were killed in the last century. Today the few thousand that remain around Australia face a new threat – the expansion of the offshore oil and gas industry. IFAW is determined to secure critical blue whale habitat from harmful industry and increased shipping.

The blue whale (scientific name Balaenoptera musculus) is the world’s largest animal, almost as big as a Boeing 737 and even larger than the biggest dinosaurs.

In Australian waters there are two subspecies of blue whales: the Antarctic or southern blue whale (sometimes known as the ‘true’ blue whale) and the pygmy blue whale.

Antarctic blue whales may exceed 33m in length and 180 tonnes in weight. Despite being called ‘pygmy’ blue whales, this subspecies can still grow to 25m in length.

As southern blue whales feed mainly in polar waters it is likely most blue whales sighted in Australian waters are pygmy blue whales.

Known areas of critical importance for blue whales are feeding areas around the southern continental shelf, notably the Perth Canyon, in Western Australia, and the Bonney Upwelling and adjacent upwelling areas of South Australia (Duntroon Basin) and Victoria.  

What’s so special about the Bonney Upwelling?

An upwelling is an ocean phenomenon that involves wind driving dense, cooler and nutrient rich water towards the ocean surface.

The Bonney Upwelling is a feasting ground for krill and other prey species. In turn, the blue whales feed on the krill.  Other predators such as fish, dolphins, seals, penguins, albatross and other seabirds also hunt for food there. The upwelling is also a productive fishing ground, in particular for rock lobster.

The Bonney Upwelling blue whale feeding area extends from Robe, South Australia, to Cape Otway, Victoria. Blue whales also feed further west in the Duntroon basin to the west and south of Kangaroo Island.

The same richness of life that sustains so many species is also the organic origin of suspected pockets of gas underneath the blue whale feeding grounds. This has attracted oil and gas companies to the area in recent years.  Oil and gas exploration involves the use of seismic surveys to search for oil and gas under the ocean floor. Seismic surveys use a series of intense air-gun blasts to do this, introducing high levels of noise into the marine environment, in the same frequencies blue whales use to communicate.

Like all whale and dolphin species, blue whales have a highly refined acoustic sense with which to monitor their surroundings. They use sound to navigate, locate prey and predators, attract mates, and for social interactions. They are extremely sensitive to man-made underwater noise pollution.  Acoustic disturbances, such as seismic surveys, can force whales away from important habitats, cause stress, disorient them, mask whale calls, thus inhibiting communication and, at closer range, can cause temporary or permanent damage to their hearing.

Every year the government announces new areas to be opened up for oil and gas exploration.  The continued expansion of the industry into critical whale habitats is going unquestioned both publicly and within government. The cumulative effect of successive seismic surveys and increased shipping traffic in critical whale and dolphin habitat is not being taken into account and risks forcing endangered whales to avoid these areas or face potentially permanent damage to hearing which they rely on for finding food, mates and avoiding prey.

Some areas, like the Bonney Upwelling, are simply too important to be handed out for exploitation without any public discussion or community involvement.  IFAW is working to ensure that  these areas, in particular critical whale and dolphin habitat, are set aside and kept completely off limits to the oil and gas industry, while also aiming to improve regulations to better protect whales and dolphins where industry operates.