It has been estimated that at the time of first European contact, the absolute minimum pre-1788 population was 315,000, while recent archaeological finds suggest that a population of 750,000 could have been sustained, with some academics estimating a population of a million people was possible.
In the 19th century, smallpox was the principal cause of Aboriginal deaths. Smallpox is estimated to have killed up to 90% of the local Darug people in 1789.
The first massacre of Tasmanian Aboriginal people occurred at Risden Cove in 1804, when Lieutenant John Bowen and his troops fired on a group which included women and children. By 1806 clashes between Aboriginal people and settlers were common. The Tasmanians speared stock and shepards; in retaliation Europeans gave them poison flour, abducted their children to use as forced labour, and raped and tortured the women.
Mass killings of Tasmanian Aborigines were reported as having occurred as part of the Black War.
In combination with impacts of introduced infectious diseases, to which the Tasmanian Aborigines had no immunity, the conflict had such impact on the Tasmanian Aboriginal population that they were reported to have been exterminated..
In February 1830, the government offered a bounty of £5 per adult and £2 per child, for Aborigines captured alive.
By 1900 the recorded Indigenous population of Australia had declined to approximately 93,000.
Goulbolba Hill Massacre, Central Queensland a large massacre involving men, women and children. This was the result of settlers pushing Aboriginal people out of their hunting grounds and the Aboriginals being forced to hunt livestock for food. A party of Native Police, under Frederick Wheeler, who had a reputation for violent repressions, was sent to "disperse" this group of Aboriginals, who were 'resisting the invasion'. He had also mustered up a force of 100 local whites. Alerted of Wheeler's presence by a native stockman, the district's aborigines holed up in caves on Goulbolba hill. According to eyewitness testimony taken down from a local white in 1899, that day some 300 Aboriginals, including all the women and children, were shot dead or killed by being herded into the nearby lake for drowning.
In 1833 or 1834 tension turned into a full fledged conflict in a dispute over a beached whale. The Convincing Ground is located in Portland Bay southwest of Melbourne, near the coastal town of Portland in the Shire of Glenelg and is listed on the Victorian Heritage Register.
Reports say up to 200 Aborigines were killed, including women and children
George Augustus Robinson visited the site of the massacre in 1841 and talked with local squatters and made the following official report:
Among the remarkable places on this coast, is the 'Convincing Ground', originating in a severe conflict which took place in a few years previous between the Aborigines and the Whalers on which occasion a large number of the former were slain. The circumstances are that a whale had come on shore and the Natives who fed on the carcass claimed it was their own. The whalers said they would 'convince them' and had recourse to firearms.
The reason for this uncertainty over casualties and the actual date of the massacre appears to stem from the fact that the incident was only reported and documented several years after its occurrence.
Gippsland squatter Henry Meyrick wrote in a letter home to his relatives in England in 1846:
The blacks are very quiet here now, poor wretches. No wild beast of the forest was ever hunted down with such unsparing perseverance as they are. Men, women and children are shot whenever they can be met with ...
I have protested against it at every station I have been in Gippsland, in the strongest language, but these things are kept very secret as the penalty would certainly be hanging.
For myself, if I caught a black actually killing my sheep, I would shoot him with as little remorse as I would a wild dog, but no consideration on earth would induce me to ride into a camp and fire on them indiscriminately, as is the custom whenever the smoke is seen. They [the Aborigines] will very shortly be extinct. It is impossible to say how many have been shot, but I am convinced that not less than 450 have been murdered altogether..."