biology

Recent history of southern right whales in Australia

Southern right whales are currently listed as an endangered and migratory species under the Commonwealth Environment Protection and Biodiversity Conservation (EPBC) Act 1999, after depletion to near extinction as a result of commercial whaling in the 19th century. Following the protection of the species from whaling in 1935, the Australian population has been slowly recovering. The first evidence of recovery was recorded in the 1980's. The long lag time of almost 130 years between collapse of the population and detectable recovery has been attributed to the intensity of unreported catches by the Soviet whaling fleets. 

Pre-whaling abundance estimates of southern right whales range from 66,000 to 198,000 worldwide. The last estimate for a combined southern hemisphere abundance of southern right whales was in 2008, with a total of 15,700 whales, between 24% and 8% of pre-whaling levels. The estimated recovery rate for the Australian population of southern right whales is 7% per annum by John Bannister of the Western Australian Museum (2014). However, within the Australian population the recovery has not been consistent across sub-populations. 

The eastern and western sub-populations

Southern right whales in Australia are recognised as belonging to two sub-populations; the south- western and south- eastern. The south-western sub-population occupies areas between Cape Leeuwin Western Australia and Ceduna South Australia, with an estimated population size of approximately 2,500 individuals (Bannister 2014). In contrast, the south-eastern sub-population consists of fewer than 300 individuals. Their range follows along the south eastern coast, including Tasmania and not further north than Sydney. To date, the south-east subpopulation shows little evidence of increase (DSEWPaC 2012).