I found a spot right next t my house about 10 miles from the ocean where the mullet had migrated up this little sorm drainage ditch, I can't get them to bit but have had pretty good luck snagging them as they seemd to be trapped or just massively schooling. The water is stagnant, polluted, very shallow 18" and pretty much black but doesn't seem to bother them. I cut them open and they smell good but I haven't got the guts to eat them yet. I am pretty sure the black is just from rotting vegetation and the pollution is run off from the streets.