Depends upon the AR provided?
The Poor Knight Islands as a NO TAKE ZONE proliferated both number and size of fish in the area that the once angry Fisherman were happy chappies 6 years later with the 'Spillover' effect.
I'm not a big fan of Ex-Naval Ships being 'dumped' under the excuse of 'Artificial Reef' as not every 'dumped' ship attracts aquatic life, let alone proliferates aquatic numbers and life. Many don't.
Ex-Naval Ships are now mostly dumped for Scuba Diving Tourism, mostly in regards to Photographers, Tech Divers doing their 'Wreck Specialty' Certification and all things concerning $$$ ...no real concern for enhancing Aquatic Life.
If they did, they would have spent $3million (eg: Ex-HMAS Adelaide at Avoca, NSW) better by having a purposely built and designed AR that would have a far greater success rate for Aquatic Life towards proliferation of numbers and size.
Majority of Aquatic Life upon Wrecks & 'dumped' ships - accumulates 'externally'. Only silt, a Wobbegong and Bullseyes reside further in.
The Yongala is a good example of much life around a Wreck, but many 'dumped' ships still have little life upon them even after 15 years. I've dived the immense Lermontov (NZ) and the Tugs of Eden - both have 'some' life around em, but nothing amazingly extrodinary.
Max Gleeson's videos upon Wrecks of NSW is probably the best collection to get the best impression of Aquatic Life around Wrecks as unlike most 'Commercial' Diver Doco makers, Max gets the 'Panoramic and whole Wreck' shots upon very clear viz days.
VARS's (Victorian Artificial Reef Society) has a motto "Trash for Treasure". Victoria dumps heaps of ships outside Port Phillip Bay, mostly for Dive Tourism - a metal version of the GBR.
Alas, 'dumping' ships leaves the door open for 'anyone' to dump 'anything' under the excuse of Artificial Reef, even with a lil' green sticker on it
I could dump a stolen car and call it an AR
Nippon and USA use gigantic floating barges to dump MEGATONNAGE of rubbish out into the 'deep' sea.
I guess Pilots are right when they say to me
"We fly up to Heaven and leave the Toilet behind for you Divers to clean." Proper research and design for that particular environment under consideration for an AR would be far more successful in stimulating growth in size and numbers. When the house is full, the kids move out and that's where the Fishing Industry will benefit in a sustainable and long term way.
Currently, Commercial Fishing (if not Recreational too?) is now free to fish in all/any Reserve or Sanctuary Zone.
Why?
Many reasons I'm sure - like: they have run out everywhere else due to stupidity.
Because they can thanks to Politians, rather than Conservationists.
Money$$$ more than need to feed.
..and more.
Anything with an 'open overhang' provides great stimulus for Aquatic life.