we get that alot. Usually if you get 1 undersize or up to 550mm you get 5/6.

Just gives you a good idea of what ground to avoid.

Northwest corner of rotto in the 35- 45m line is loaded with them, we dont even go to our marks out there anymore - instead have been going out of Two rocks, still get undersize dhuies but not as many as off rotto. Over easter I went out just west of Roe Reef  in 25m water, never fished that area before, there was a string of pots, same thing got 4 undersize dhuies and a ripper blackarse that was bigger than the dhuies so was pleased with him.

 A couple of Fridays ago out off Mandurah we got 6 undersize and two just shy of 600 mm. Seems to be a few coming through. Got one 470 mm on the James Service last night too chasing Pinkies. Hard work getting past the skippy last night though. 

 Interesting Matt that you say ground to avoid yet in previous yrs this same type of ground has hidden many a good Dhuie!! This trip out we tried many different spots & ground & even out to the edge of direction bank. I still think that the size limit should go up to 600. At least then at 600 it is just about worth keeping one.

We usually have a 600mm rule on the boat, but on those real bad days the 500mm dhus are looking pretty good.

We get alot of undersize dhus but seem to get alot on some days, not so many others.

For instance last time I went off two rocks, bagged out got a nice 15kg dhu, lost another big suspected dhu and filled the esky with a baldy and a few breaksea.

Next day wanted to get my dad on a good one, exact same area, same spots, A dozen or so dhus ranging from 500 to 600 and threw them all back sure we were going to get that big one and came home with nothing.

Speaking of norwest rotto, last two times out of there we got no dhus, but bagged out on baldys. Some stonkers too. The bigger more prominent lumps too which we normally avoid

 I also agree with the 600 mm rule.Give them more time to breed.

So let me get this right slam, from your first post,  (realistically if we dont let them get to the breeding size the fishery will fall apart. I think i read somewhere that they need to be 600 plus?) so you want to raise the size limit so that everone is taking breeders??? plenty of good fish out there mate, but for some reason some days they wont chew, or for what ever reason you cant catch them, i think the fisherie is better than it has been for a long time, cant seem to get away from the dhus most days.

 Surely we are better off increasing the size limit Robertmc and give them a chance to breed before catching them than catch them before breeding is achievable? Am I missing something in my statement?

i agree that there are more dhuies out there albeit small ones but as I previously said if we catch and keep before breeding occurs then the inevitable will happen.

I would like to know how/why Fisheries came up with the 50mm figure if the fish don't breed until they are at least 600+.

From a few things I have read this same question can be aimed at a number of species that are allowed to be kept before they reach breading size, this fails to make sense to me catching and keeping before they have had the chance to breed.

 Bigger they are the harder to release

All the information I've read suggests they mature at around 35cm. 

For such a high risk fish, I would expect fisheries have have set the size limit so that they get a couple of years breeding under their belt before they have the potential to be taken out of the system.

but I also agree with upping the limit to 60cm, could only be a good thing imo. There are stacks of little ones in geo bay.

Surely a lot of little dhuies is a good thing? 

 dhu first spawn at 300-350.  Bigger fish however produce exponentially more eggs.   And as you said jim a lot of small ones is a good thing.

 Dhu's have had a few seasons to spawn by 500mm. That is why there are so many small ones.

Better than upping the keeper size would be to introduce an upper size limit also so the bigger breeders that produce 10-15 times the amount of eggs can continue to do so until their natural deaths. Already done with a few species around the country.

The biggest problem of course is Barotrauma and Dhuies suffer more than most. Big or small if you reef up a dhuie and know in your heart it is going to die when released, should you release it? The law says yes and the penalities are high so most people will. If there was an upper limit and you were targeting Snapper, hooked a 850mm Dhu, and knew it would die when released. What would you do??

Merv