Pretty sure you cant target them during the closed season (June 1st to August 31st). I wouldnt worry about chasing them anyway, they head down to the estuaries to breed. Any that are left wont be to keen to bite due to the cold. I would wait until it starts to warm up a bit, a stormy afternoon in october/november is always the best time to chase them. Definitely tried the right lures.
Are there yella's and cod in the Brisbane river?