The island of Zannone, since the prehistorical epoch was surely used as place of settlement. The main settlement, more likely a roman villa, probably occupied a space that in the Middle-Ages was used for the construction of a monastery. Belonging to the roman villa on the south-west side of the island , there was also a fishery entirely obtained from the rock, situated in a little inlet, that was probably also used in the ancient times as a landing-place. The fishery is formed by a covered pool completely closed in the rock.
To accede to the fishery there are nine steeps of irregular shape graved in the rock; on it's southern wall opens a staple that works as a tributary of the fishery. The staple is not rectilinear; in fact at half of it's length it bends lightly towards the sea. Besides that, it ascends lightly respect to the level of the fishery to permit the entry of the water and in the same time to avoid it's natural reflow. Probably there was a gate to regulate if necessary the flux of the water and to prevent the getting out of the fish.