As you drive north from Dubrovnik and up into the Peljesac Peninsula, it's impossible not to notice all the oyster farms dotting the water (also impossible not to notice, and stop at, all the winemakers who offer tastings).
The towns of Ston and Mali Ston are connected by a medieval wall, which apparently you can walk. We were only interested in the oysters. There are a couple of restaurants along the waterside in Mali Ston. But the oysters all come from the same place, so I suspect there isn't a huge difference. Kapetanova Kuca was a fine choice. The oysters were briny, fresh, and fleshy, in a good way.