Blue Whales in Australian Waters
Blue Whales are categorized as Southern Blue Whales and the Pygmy Blue Whales. A less popular category is the Northern Hemisphere Blue Whales. The Pygmy Blue Whales are found at north of 55∞ S, while the Southern Blue Whales are found at the south of 60∞ S.
Blue Whales are mostly found in four locations in Australia. The first is the Perth Canyon off Rottnest Island in Western Australia (one of their feeding areas) during December to April. They can also be seen feeding at the Duntroon Basin, South of Australia during November to April. They also feed at the Bonney upwelling, south-east of South Australia, during the same time. They also feed at the Victorian waters at the same period. The feeding areas are the most notable for whale aggregation in Australia, and the noted whales in these regions are likely to be the Pygmy Blue Whales because this is summer. During winter, the blue whales migrate for breeding but the locations remain unknown. Southern Blue Whales mostly feed in polar waters and, therefore, might not be found in Australian waters.
Although the Blue Whales move to different places at different times around the Australian coast, they move to various coast regions mainly for opportunistic feeding and migration. Their movement at the coastal waters is also dependent on the annual conditions.
Distinguishing Blue Whales from other Species
The Blue Whales are considered the largest animals in the world. They are luminous pale blue in color or aqua when submerged in water. The male Southern Blue Whales grow to about 31 meters, while the male Pygmy Blue Whales grow to up to 21 meters. The female Southern Blue Whales grow to up to 33.6 meters and the female Pygmy Blue Whales up to 24.4 meters.
The Blue Whales can be identified by their grey skin and the mottled patterns on it. In front of their blowholes is a visible “splashguard.” A single longitudinal ridge can also be seen running forward on their rostrum. They have a strong blow measuring about 10 m. A dorsal fin is located on a long smooth back. The fin has various shapes and is set towards their tail. Those living in the Bonney Upwelling (South Australia) and Perth Canyon (Western Australia) can be identified by the lamprey bites or the healed cookie-cutters located on their tails. It is assumed that these tail wounds and bites are inflicted in tropical waters.
Watching Blue Wales
Blue Whales can be found in Australian waters in places such as Duntroon Basin, Bonney upwelling, Victoria and Perth Canyon off Rottnest Island, in groups of two or in singles. They move in twos in order to minimize competition for rare prey or food. A larger number is visible in the Southern Ocean where there is plenty of food, and Antarctic waters where there is a large subsurface krill swarm. It is interesting to observe large number of whales together in these places.
South Australia and Victoria waters are characteristic of “racing groups” of Blue Whales. They are interesting to observe. In this case, three whales move together while frequently changing directions. This is assumed to be a courtship and social behavior.
Although it is known that they migrate for long distances to breed during winter, the locations are not known. However, some will remain in Antarctic waters in winter period. Blue Whales also make calls at low frequencies. For instance, Pygmy Blue Whales found in the Western Australia make calls of frequency in between 10-30 Hz. However, these calls vary depending on the species and the oceanic region of location.