Time to play in the Derwent
Southern right whales put on many boisterous mating displays this year on the lower Derwent River, especially in Fredrick Henry Bay, and seasoned observers reckon it was the best display in decades.
They’re now [August 2005] on their way north, but indications are that they will be back again in 2006 with increased numbers.
Historically, the Derwent Estuary was one of the favourite haunts of the southern right whale, Eubalaena australis. In the mid-1800s, the Reverend Knopwood recorded that residents of Taroona complained of being kept awake by the whales’ loud snorting noises.
At times, it was considered dangerous to cross the estuary in small boats due to the large numbers of whales — sometimes as many as 60 at a time.
Whaling was a significant activity in Australia throughout the first half of the 19th century, and Hobart was an important whaling centre.
Whaling continued intermittently until the 1890s, by which time the southern right whale had been hunted to the edge of extinction — of an estimated 100,000 whales, over 26,000 had been killed in Australia and New Zealand alone.
The name ‘right whale’ was coined by whalers, who considered these the right or best whales to catch. They were slow swimmers and docile enough to approach safely. Once killed, their large amount of fat made them float, permitting easy collection. Finally, they yielded large quantities of valuable whale oil used for lighting, heating and cosmetics and their long baleen was prized as a source of whalebone.
Today, the southern right whale is among the rarest of all whale species, with an estimated remaining population of 2000 to 3000 individuals, of which 600 to 800 visit southern Australian waters to mate and calve. Since the 1980s there have been confirmed signs of a steady recovery in numbers.
Southern right whales follow an annual migration route, travelling about 5000km in each direction between Antarctica and the southern coasts of Australia, South America and Africa. Summer months are spent in Antarctic waters, feeding on the dense phytoplankton blooms found in the Southern Ocean at this time. The whales then travel north, to warmer temperate waters to give birth, rear their young and breed during winter months; during this time they do little or no feeding, surviving on their fat reserves.
The southern right whale is a slow, lumbering swimmer, but can be acrobatic, particularly during courtship displays during which the whales may breach, wave a flipper above the surface, flipper-slap, lobtail and headstand.
The Derwent and other bays and estuaries around south-east Tasmania were once established calving grounds for this species. Typically, they arrive in Tasmanian latitudes on their way north from about May onwards, with numbers peaking in June and July. Some linger but most continue on to mainland Australia, passing through Tasmanian waters again on their way back south for the Antarctic summer.
CREDITS: The photographs were taken by Damien Conner of Tasman Sea Charters during his whale watching tours in Fredrick Henry Bay. The tours take off from Lewisham and Dodges Ferry when the whales are in. Make a diary note now for next year’s display and call 1300 554 049 come May or June.