Hi.
I called the DPI recently and they sent me some info on the regulations for spearfishing.
You aren't permitted to use breathing apparatus other than a snorkel.
Of course there are closed waters to keep away from - I'm familiar with Gold coast laws, but not sunshine coast.
This could help: http://www.dpi.qld.gov.au/cps/rde/dp...7_ENA_HTML.htm
Don't think the area you're talking about is on the list of closed waters.
All normal undersize rules apply and be careful to judge the size accurately before spearing anything. If you did kill an undersize fish it must be released regardless.
Apart from that, you can't spear certain species such as Blue groper, but the DPI can tell you the exact rules. There's lots of info they can send you for free that can't be found online. Their number is on the website under contact us.
My method is to only spear what I KNOW I can legally take. All I bag is one or 2 luderick and never get my spear near a species I'm unsure about. Wait till you get home and look it up for next time if you're doubtful.