A spearo with a speargun is really no match for most fish, at least having to breath-hold means that you give them half a sporting chance. In NSW you certainly can't spearfish on scuba, and it doesn't stop the divers there pulling in some very respectable fish. We used to hunt from between 5-15 metres, all breath-hold, consciously slow your heart rate, hang on the bottom and throw sand or strum your rubbers to attract the fish, it's all part of the thrill of the chase. Occasionally scuba divers (non spearos) would come past and we'd swim down to them and have sign language conversations. The vast majority of table fish can be shot from swimmable depth anyway.
The only time I can see scuba being required for spearfishing is hunting some of those big (100kg +) tuna.
I'll say it again: If you can't shoot a feed by holding your breath, (and by that I mean one shot, one kill, one meal) then you really should take a good long look at yourself.
...last i went south last year i dumped everything and just practiced freediving with a hawaiian sling and and a short gun it's fantastic to know how much lung power you can do in an hours time
