Australian Humpback Whale Migration
Australian Humpback Whales have a never ending cycle of migration. They undertake this migration every year up both sides of Australia east and west. For the purpose of this web page we will concentrate on the Australian East Coast migration.
Australian Humpback whales spend summer in Antartica feeding on krill and small fish. Scientists state that they begin their 10,000 - 11,000 kilometre migration north around June however this year (2011) Humpback Whales have been observed in Queensland in May.
Juvenile males have been observed to be the first whales, leading the migration. Mothers and calves tend to follow behind being some of the last to arrive in northern waters.
The bulk of the whales will migrate north from June to August to tropical waters in Queensland to give birth to their new calves.
Humpback Whales in Queensland have been observed as far north as Cairns and the Coral sea with frequent sightings in the Whitsunday Islands, Hervey Bay, Moreton Bay and a thriving whale watching tourism industry has developed over the past 18 years or so.
Female Humpbacks will use protected bays to stop briefly to feed young calves and fatten them up before they reach the freezing waters of Antartica.
The whales will also visit bays along the way in New South Wales and have been seen in Sydney Harbour and Pittwater Bay.
They commence their trip back south in late July, August with most whales having left Queensland waters by mid November each year as they head back to Antartic waters.
The migration is not an easy one so all whales and calves must be in good condition to make this epic journey.
The trip is fraught with danger as there are predators that view the Humpbacks as a food source.
It seems that the Humpback Whale is not very safe wherever it is.
While in Antartica they have been hunted by Japanese whalers. Orcas are the main predator of the Humpback Whale with most whales showing signs of attack.
Drag marks of Orca teeth can be seen on many whales tails. The Orca likes to eat the tongue of a whales.
Sharks are also on the list of predators with Great White sharks actively migrating at the same time as the whales do following them looking for the weakest and waiting their chance to feed. Some Humpback Whales also bear the unique tell tale rake marks from Great White Sharks and the Great Whites are observed following the whales.
Tiger Sharks, whaler sharks are all very common in tropical waters. Once an attack by a number of sharks commences it is a very determined assault and sharks will follow a weakened whale nipping and biting until the whale cannot swim anymore. The longer the whale swims bleeding the more sharks that will arrive to participate.
Orca's while they have been spotted from time to time in tropical waters do not seem common in northern waters.
Nets along Australian beaches designed to deter sharks have also trapped whales.
A weak or sick whale will be targeted and dispatched by predators leaving little behind as evidence of the attack.
Strikes by ships also occur with one large whale spotted with propellor marks running the length of it's back. Whales also get tangled in fishing gear and cray pot ropes.
The Humpback Whale population in Australia is estimated to be around 15,000 whales at the present time (2012) which is a far cry from what Captain Cook saw when he arrived in Australia.
It is noted in Captain Cooks logbook from the Endeavour that at the entrance to Sydney Harbour there where whale spouts as far as the eye could see. We just don't see that thesedays and that tells you the impact whaling has had on the Humpback numbers.