You'll catch more edible fish in the marina than outside it.  Use a tiny barbless hook on very fine line and use bread paste - I mean a very fresh white loaf; pinch the bread out of the crust and cast it upon the waters near the piers and boats.   The fish are very hook shy so if you don't have a hit then it's probably your presentation that's at fault.  Keep the ducks and gulls out of it.  Let the paste sink and keep right out of sight.  The big fish will suddenly come out of the deeper water and hit the bait so be very alert.  Keep your landing net handy as some of these are quite decent fish.  Put back the mullet as they're (well) OK but not the finest, excellent for fish cakes but a rather course flesh, grey-ish but fine if you're hungry - what you want are the balck bream and the orange striped bream, both named accordingly.  They'll gorge the bait so have a tool ready to put those back you don't want.  I use a keep net so I can decide at the end of the bash what I want to keep and what I want to return.  Anything smaller than BIG is not worth killing as the bones spoil the cooking.  Go for a few big fish and have fun!!!!!  Where's your boat?  PM me for a a meet up?