I had a coworker that was neighbors in Alabama Port with an oysterman that brought back the saltiest oysters of any. He had a specific reef that was just great tasting and he sold them very cheap to my coworker.
When we lived in TX in the 1970s (Quail Valley, Missouri City on the SW side of Houston) they used to pack it in ice and bring it up from Galveston -- fresh caught -- and sell it from trucks by the side of the road. Or, the fish mongers would drive through the neighborhoods and sell it door to door.
Gubmint probably passed an ordinance preventing that. I bought a lot of Gulf shrimp that way.