your guess would be as good as anyone else's. 

Generally all demersals are pretty slow growing. A 25kg dhuie was once a common thing. 

The best way to avoid future problems is to be proactive now. 

at another time than the demersal ban?

 Well the same methods are used to catch these fish, same rigs etc although heavier. You would have to prove you weren't targeting Dhu's or whatever else. 

dont deep droppers still catch snapper out there? how does bycatch "snapper" release from 150m? what depth is deep drop and how would fisheries police that?

does seem strange that deep drop is part of the ban but there are plenty of reasons why i spose

How complicated are the rules already.

If they split closed seasons how would they know where you were fishing.

People would just say they are targeting whatever was legal at the time.

Simplicity is sometimes a much better solution.

As many of the deep fish are slow growing (like most colder water fish) pushing more pressure onto them may not be a good thing.

Also how many inexperienced anglers will head out in boats that arent suitable just so they can get their feed.

Plenty of other options for a couple of months

 "People would just say they are targeting whatever was legal at the time."

Can do that now?

 A lot of the deeper species are spawning around this time as well! Guaranteed if the deep species weren't protected you'd have 50-100+ boats in the trench every weekend the weather played the game! 

 Why do the landbased guys cop the demersal ban too ? There are many questions regarding fishing regulations in WA and too many rules as it is. 

Lots of people still cant work out what a mixed bag limit is, and size restrictions within those bags on certain species. 

 The ban has nothing to do with spawning, it was implimented to reduce the total demersal catch by 50%. And it achieved this straight away according to fisheries.

 So that deep water species don't end up in the same state as the others prior to the bans being introduced.  You can still fish them 10 months of the year.

I believe the ban has had little effect on your metro fishery.
It was the removal of commercial demersal fishing Two Rocks-Mandurah.
How do I come to this conclusion?
Because we also have the ban but also commercial fishing and haven't seen a noticeable improvement as is widely spoken about here anecdotally in the metro area.

Don't take this as being anti commercial, this is just my observation.

i would tend to agree with rob above in his view/observation

while other demersal management changes have helped the biggest improvements have come imo from the removal of most rock lobster boats being able to take scale fish and the ban on metro commercial fishing

the improments have been the biggest within the metro area , its also where you hear the most issues with sharks of all varietys in recent years

and again im also not anti commercial

hezzy

 Everyone complaining about the demersal ban and here we are moving south to target dhuis. I guess the price and demand goes up during the ban...

burnz
one of the negatives is the increased activity by commercials in the south , this has resulted from being pushed out of the metro imo

it does not make good pr for some commercials who like to run shark net especially in close down south , its legal , but it sure smashes the inshore stocks to hell in many locations along the capes coast
the wetliners are more aware of the need for balance with their fishing imo

given the rec ban was only to reduce effort it would be much better to have the commerical ban and the rec ban on at the same time , working together to manage the total demersal fishery

hezzy

 Think you might find fisheries research might indicate that this is the time of year most species spawn ,

 Bit late for the pinkies and bit early for the dhu and baldies?

Maybe mate yeah , always found up north from September till about mid November was spawning time , you could target fish around those times no worries, spangos , estuary cod and Malabars , reds. Rankins etc.probably right though , I think pinks spawn a bit earlier. can't tell you much about the dhuies. Deep water was always around now to . not that effects me much but I think its a great move. 

We generally fish Deep between April to July when the conditions are more suited for a deep drop, But last week we went to couple of our blue eye spot and fish from both spots had plenty of roe.

Never seen that in fishes caught during April to July.

So it looks like the ban is set for a reason.

I am no expert, just my observation.

 I'm one of the younger guys who hears old dogs always boasting about how "it used to be" with demersals, and I'm jealous of the greater abundance of larger fish they had available then. I would feel dissappointed if I was having to tell young people when I'm old how "it used to be" about deeper species, so I think its great limits are here now, not later on when they Are more than needed and often too little too late.