Bloody things are everywhere, undersized whiting are probably the most common fish I catch. Agree with David that once you suss out where they hang out getting a feed isn't too hard, you can even choose between lots of smaller ones you need to get the measure out for, or fewer but much larger models you only need the camera for.
Just this Saturday (glorious day) drifting around in about 3m off Port Gawler my Dad managed a 35cm model, among other stuff, on an SP, If that is a thing that can happen so close to Adelaide then they must be doing OK.