Suspended between earth and water, the valli are the basins or hatcheries enclosed by embankments for trapping or breeding fish; they extend beyond the Romea state road in the Campagna Lupia area, offering one of the most beautiful and fascinating lagoon landscapes in the world, and particularly magical in certain red-tinted sunsets. They are the fruit of thousands of years of man's efforts to adapt the environment, to contain the sea or to reclaim land. The nine embanked basins are state property but are let to private enterprise for fish farming: grey, mullet, bass, eel, sole and gilt-head.

Valle Averto

The pulsing heart of this part of the lagoon is the two hundred hectare area of Valle Averto, managed by the WWF that has breathed life into a nature sanctuary where an ideal ecological system has been recreated for the repose and nesting of various species of migratory birds. Equipped with a 'museum of the area' with a restored boat shed and workshop, reforested over the last few years with the original flora and the replanting of white and black poplars, willows, sycamores, field maples, common alders, common oak, the sanctuary shelters many varieties of animal which can be seen by following the camouflaged paths or from the reed lookout huts. among the mammals is the water buffalo (introduced some years ago), the nutria, badger, fox, martin, weasel, and the pole-cat. Among the wintering birds are the mallards and the water-crow; the resident birds are the grey heron, great white heron, kingfisher, marsh harrier; and the mute swan. In summer it is possible to observe the purple heron nesting, the dwarf heron, the stilt-bird, common redshank, spotted redshank, greenshank, spoonbill, and the sandpiper. During the migration period the fish hawk, mud-dwellersand many species of duck. Every now and then the red-crested pochard shows himself that has even been known to nest in the area and therefore has been chosen as the heaven's symbol