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Southern right whales right at home in Tasmanian waters

Southern right whales right at home in Tasmanian waters

 

When Europeans first settled in Hobart in 1803, it was reported that “you could walk across the Derwent on the back of the southern right whales” and residents were kept awake at night by the noise of their blowholes. Local waters were a stronghold for the whales. Thousands of animals travelled north from their summer southern feeding grounds to give birth, mate and socialise in Tasmania’s sheltered waterways each winter.

Shore-based whaling rapidly developed into a thriving industry, with the first southern right whale killed in Tasmanian waters in 1804.  At the peak of the whaling industry in Tasmania in 1839, more than 60 whaling stations had been established and more than 1000 whales were killed in that year alone.  During just four decades, some 7745 whales were killed by the Tasmanian whaling industry, resulting in their disappearance from the Derwent and surrounds.  This signalled the end of the inshore whaling industry, but a switch to offshore pelagic whaling meant southern right whales continued to be hunted throughout the southern oceans over the next 100 years.

Southern right whales were prized by whalers. They were called right whales because they were the right or best whales to kill. One reason for this was that their large amount of fat made them float after harpooning, so  they were easy to collect. Being very slow swimmers, they were sufficiently docile to approach. Most importantly they were full of the highly prized oil used for lighting, heating, cosmetics and crayons.

Offshore whaling with the 'Alladin' and 'Jane' 1849Even as recently as the 1970s, southern right whales continued to be hunted (albeit illegally by this time) in waters just 200 nautical miles south of Tasmania.  In total, an estimated 150,000 southern right whales were killed in the southern hemisphere – more than 26,000 in Australia and New Zealand alone – and the global population reduced to as few as 300 individuals by the early 1900s.  They were the first species of whale to be protected in 1935 because so few were left, and today the southern right whale is listed as endangered under Tasmanian and Commonwealth legislation.

whales1It is generally recognised that there are two discrete populations in Australia, the south-west and south-east (which includes whales using Tasmanian waters) Australian populations.  Similar to southern right whale populations off South Africa and Argentina, the south-west Australian population is recovering at what appears to be the maximum biological rate, although they still have a long way to go before returning to pre-harvest numbers.  Our south-east Australian population however remains critically small, with perhaps as few as 600 individuals, and to date there is limited evidence of an increase in this population.

whales2Biologists from DPIPWE’s Princess Melikoff Trust Marine Mammal Conservation Program (PMTMMCP) conduct an ongoing monitoring program for this threatened species in Tasmania.  One of the primary tools for monitoring the population recovery of southern right whales is the use of photographs (predominantly taken from the air) of individual whales.  Each whale has a unique pattern of callosities on the head. Callosities are the lumps made from the living fauna of barnacles, whale lice and parasitic worms which seem to attach to these whales almost immediately after birth. They act just like fingerprints, allowing biologists to identify individuals.  This enables them to track whale movements through space and time, obtaining valuable information about social and breeding behaviour and areas of high importance.

The placement of historic whaling stations provides one of the best indications of locations that were important to southern right whales prior to the establishment of the industry.  The first whaling station in Australia was established at Ralphs Bay on the River Derwent in 1806 and many more soon followed. They were deliberately built as close as possible to areas where whales congregated in large numbers, such as Slopen Island at the head of Frederick Henry Bay, Bruny Island and other sheltered bays in Tasmania’s southeast where it was noted that “the bays on the southern and eastern side of the island are the resort of a number of whales, which come here to suckle their young in still waters”.

whales4Now it is these places where we are beginning to see the whales return and make use of these sites again; however these days the bays are favoured locations for boating and fishing activities for the same reasons these sheltered waters made ideal sites for hunting whales.  With sound management and a concerted effort by vessel operators to minimise disturbance, it is hoped that in the future these places will once again be the resorts of whales.

Since 2005, the PMTMMCP has been actively developing a catalogue of individual southern right whales by undertaking aerial surveys in response to all suitable sightings of southern right whales reported on the marine mammal hotline (0427 WHALES).  Individuals are archived into a Tasmanian database and shared with researchers in Victoria and NSW to build up a catalogue of the south-east Australian southern right whale population.

whales3In the winter of 2012, the PMTMMCP catalogued a record number of southern right whales, with 33 individual whales entered into the Tasmanian database.  In previous years, the majority of photographed whales appeared to spend only a small amount of time in Tasmanian waters as they moved north, presumably travelling to the large established aggregation sites off the southern coast of mainland Australia.  However in 2012 many whales remained within the Frederick Henry Bay and Bruny Island region for an extended period, in some cases up to two months.  These whales were also exhibiting the kinds of socialising and mating behaviours that we would expect of whales for whom Tasmania was a destination rather than a staging location.

PLEASE REPORT ALL WHALE SIGHTINGS ON THE MARINE MAMMAL HOTLINE

0427942537  (0427 WHALES)

 

Reports from the public are important as they contribute to further understanding of these threatened species and thereby assist the national recovery efforts.

 

Top painting of whales being hunted is “Offshore whaling with the Aladdin and Jane”; painting below is “The Rounding”. Both by William Duke and courtesy of the Tasmanian Museum and Art Gallery Collection.

Story and photos courtesy of DPIPWE Marine Mammal Conservation Program

This story first appeared in the Spring 2013 issue of Tasmanian Regions. You can find back issues of the magazine here