G'day Flatzie,
The only hooks i use are Big Gun,
& while not being a true circle hook, they work on the same principle.
I live in Ballina, & only fish in water 60-250 mtrs.
Fishing in 60-100 mtrs, I still strike, the fish dont always just hook themselves,
but once we get to the deep, the strike is very different..
In 250 mtrs we can still feel bites, but the strike is 6 winds of the reel,
then lift your rod tip high & see if you have weight,
if you have weight your rod tip will nearly touch the water,
swear words are often heard at this point, hehehe.
When we catch cod they are nearly always hooked in the jaw.
Hope this helps,
Muzz