Hi, have been trying to find an answer to your question, what I have found it must have been in about 1825. In the book I have it says that the number of rabbits remained small until a Victorian grazier Thomas Austin let 24 wild English rabbits loose on his property, Barwon Park in 1859 the population explosion began. The first mention of rabbits was I could find was in 1825. I have a book The Chronicles of Australia. Exactly from when I am not completely but it was well before Captain Cooke. The version goes until1992. Sorry best I can do for now. Hope it interests you.