Right now (end of august) fish can be found in both deep and shallow water, so there is no need to go deep unless you feel comfortable going deep. I mostly go up to 20 m deep. There is no specific place i would recommend to you, fish can be found everywhere. Look on google maps for a spot that's easily accessible to you and has a good and rocky shoreline, go early in the morning or late in the afternoon and be careful of boats!
Spearfishing is the most sustainable way of catching the fish. Spear fishermen are responsible for less then 1% of total fish that get caught. When you spearfish, you choose which fish to kill unlike other fishing methods which are unselective and last but not least, i only catch what i will eat, so it's not much. Cheers!
