At the mouth of the Isonzo and in the lagoon of Marano there are large areas of delta with strips of riparian forest and large reed beds that give way to salt marshes and tidal flats. Thanks to the wide variety of environments, these areas are rich in wildlife, and in birds in particular. Nutrient inputs from the fresh water provide the basis for high productivity that reveals itself in the wealth of fish and shellfish. Attracted by the richness of the fish and game, man has lived in these places with settlements of huts (casoni) that were permanently occupied by families in the Grado lagoon and by fishermen alone working in the Marano lagoon.