Po River Delta

The Po, known in past times as the Eridano, is Italy's longest river. It measures 652 km in length, has an average capacity of 1,500 m3 (as measured at the height of Ferrara), and a drainage basin measuring approximately 75,000 km2. The importance of the river makes it comparable to other great European rivers such as the Rhone, the Danube, the Rhine, and the Guadalquivir. One of the main characteristics of the Po is its delta, a landscape in constant transformation due to its typical lobed shape caused by the accumulation of sediments. This large river flows through a variety of different habitats. The final stretch is typical of water courses found in flat areas: the river is shallow, the water warm and slow-flowing; vegetation is abundant; the river bed is muddy and subject to a wide range of habitats. The main indigenous fish varieties found in these habitats are: carps, rudds, bleaks, eels, roaches, nases, common barbels, and royal perches.
These waters' predator par excellence was the pike until the increasingly numerous silurus, a Central European species, found in the Po an extremely favourable environment in which to grow and reproduce. Also numerous are fish varieties introduced in the Po in ancient times, among them: the crucian (a fish highly resistant to temperature changes and to pollution), the sunfish, the largemouth bass, and the catfish (an active nocturnal riverbed predator). The Po also hosts fish that migrate seasonally to salty habitats for food, but which then return upstream for reproduction purposes.

Among these are the twaite shad (a species whose sexually mature adults migrate in the spring to reach their zone of reproduction in the middle stretch of the Po and its affluents), and the Adriatic sturgeon, which likewise migrates from the sea to the river in order to complete its reproductive cycle. The great decrease in the numbers of these two species is due to the dams that have been built along the river, which interrupt the fish's journey and therefore do not permit them to reach their reproduction zones, and to the serious environmental degradation that has taken place in the last decade. Pollution has particularly affected the population of sturgeons, a species whose morphological characteristics permit us to define it as a real living fossil.
Moreover, the progressive degradation of the Po is profoundly changing the extant relationship between the river and the human population of the surrounding areas: professional fishers are abandoning the river because they can no longer make a living from it, and even non-professional fishers are turning to drainage canals or, in some cases, to private lakes where they must pay a fee but where they have a higher chance of catching fish. Not to mention the tourists and bathers who once came numerous to the river's shores in search of respite from the sultry summer heat but whom it is increasingly difficult to spot.
This great river of ours and its amazing delta represent an immeasurably precious natural, cultural, and social heritage, a whole ecosystem to be protected and preserved. The "park", currently still under definition, is certainly a step in the right direction for the protection of this precious environment.