Photograph by Angela Anderson
Humpback Whales are the most acrobatic of Tasmania's baleen whales. They often leap right out of the water - known as breaching.
Like all baleen whales they have a double blowhole. Distinguishing features include a 5m long pectoral fin (flipper) which is about one third of the whale's body length and has knobbly edges. Females are larger than the males, reaching up to 18m in length and weighting around 40 tonnes. They have a small but distinctive dorsal fin. The tail fin is scalloped and is often white underneath. Individuals can be identified by the scalloping pattern on the tail and the unique white patterning they have on the underside of the tail which they will often slap in the water or show before they dive.
They are blue/black in colour above (dorsally) with a lighter colour underneath with long grooves running from the mouth to navel. Close up you will notice some callosities (white bumps on the head). Generally they occur singly, or as mother and calf although spread groups of up to 20 have been recorded.
Distribution map of sightings and strandings (click to enlarge)
Humpback Whales occur worldwide and are most often seen in Tasmania during winter when they travel north from Antarctica to breed off the coast of mainland Australia and in spring on their return from their breeding grounds. They travel up both the east and west coast of Tasmania (within 10 nautical miles of the coast). East coast animals head for New South Wales and Queensland or cross northern Tasmania and join west coast animals heading for Western Australia.
They breed every 2-3 years and calves are most at risk from shark and Orca attack at this time.
Humpback Whales feed co-operatively on schools of fish and are the baleen whales most at risk of entanglement in fishing nets. They are listed as endangered mostly due to past whaling. Numbers are now improving. In Tasmania, they are often spotted on their annual migrations. Male Humpback Whales hang upside down in the water and sing.
Listen to a small portion of the song of a Humpback Whale
(Recording courtesy of Cath Samson).
Humpback Whales are most likely to strand because of illness or disability and usually they strand individually or as a mother and calf. Calves are around 4m in length at birth and are usually independent at 10m. Dependent calves cannot survive without their mother. Over 20 single strandings of Humpback Whales have been recorded in Tasmania and a similar number in New Zealand. Multiple strandings within a short period may be related to an environmental issue that is affecting the whales.