g'day charlie,
Mate might be wirth a shot at the pinkemba region near the oil and coal dispatch.. but i would keep on trying around the mouth of breaky creek. try on the easten end of the park on the corner near the green shipping beakon it there are flathead and trevally and other species there...
Keeping them and eating them is at your own risk but i wouldn't recomend eating anything outta that river, lived there the fisrt 18 yrs of my life and the mercury levels are still high, but your kids will have fun... just watch the muddy rocks they are very slippery but realativly safe apart from that..
Ps. chance of school jew at the pinkemba area aswell as mangrove jack and all sorts..