The Church of San Giacometto in Rialto is the oldest church in Venice, dating back to 421 AD.
In Campo San Giacometto, on the second column of the portico of the Church of San Giacometto di Rialto, two carved outlines — one of an oyster and one of a fish — can be seen.
These represented the minimum legal sizes allowed for sale at the market.
It was forbidden to sell or buy fish or oysters smaller than these measurements, in order to protect the fish population.
As early as 1173, an edict of the Republic set specific measurements and bans for fishing, recognizing that fishing was an important economic resource that needed protection.
At the Rialto Fish Market, you can still see plaques on the walls showing the minimum sizes for fish that could be sold.
