Ditto here. I and a few mates have made laminated charts with fish limits etc we use a marker pen everytime a fish goes into the esky, this is easy to control as the fish first are bled and then counted when several are put on ice. Marks easily removed for next trip with some metho. Generally on my boat fish have to be several cm over that set by qld fisheries, this stems from a fishing club I was on in not so long ago. At that club you could weigh in as meny species as you liked but only 1 fish per species and the minimum accepted size was 2cm over the minimum size limit. Got rid of that catch as many as you can mentality.
Our size and boat limits in particular are at times restrictive and we have rarely reached them with the exception of snapper, pearl perch or duskies, even then on my boat we were particular about we kept, some species like king fish- not at all as in the warmer waters their flesh is soft.
Sometimes I can't understand the difference in size limits between States eg pearlperch in qld is 38 m wheras in NSW it was from memory 30 cm, that is a ridiculously small fish to take imho. Maybe we should get more consensus between states on sizes but once again may never happen as I recall a scientific paper on what age duskies mature, from memory again it was at a smaller size limit the further south you went. Or maybe the figures were skewed to meet a particular agenda.
What's the answer, I don't know, certainly having volunteers at the ramps here in qld asking some very general questions is not going to give any sort of reasonable results.