Toward to extinction
of Italian fishes of sweet water!
The state of maintenance of the Italian sweet water fish is critical. 31 kinds of fishes of the waters inside on 48 they are threatened, reentering in the three categories of risk of the IUCN (World Union of the Maintenance). Among these there are six endemic kinds and six subendemiches, that live only or almost in Italy. The causes are above all the alterations of the habitats and the introduction of alien kind. The report is contained in the Plan of action general for the maintenance of the Italian fishes of sweet water, taken care of experienced by Sergio Zerunian on behalf of the Office of the environment and guardianship of the territory and INFS (Institute National Wild Life). According to the study, they are eight the kinds on which it would be necessary to assemble the efforts of maintenance: the Lampreda Padana, the sturgeon cobice, the trout macrostigma, the carpione of the fibreno, the brown trout , the carpione of the Garda, the Panzarolo, the Gudgeon of brook. These eight kinds in fact they reenter in the first two categories of threat of the IUCN («Threatened in critical way» or «Threatened») and are kind endemic or subendemiche. If they were extinguished in Italy, they would be extinct totally. «The importance of the Italian fishes of sweet water - writes Zerunian - so much doesn't depend on the number of kind (what as absolute value is relatively modest if compared with other groups of vertebrates, as for instance the birds) but from the tall number of kind endemic, 13 and subendemic, 9». Her causes of the disappearance of the fishes of sweet water they are referable almost all to the alterations or destructions of the river habitats: transformations of the use of the ground, works of drain and canalizations, transformation of some rivers in channels navigable, transversal obstructions of the courses of water (dikes, dams), excessive collectings and wastes of water for agricultural use, industrial and civil, realization of structures, industrial and urban unloadings, fittingses of piscicultur, excessive and illegal fishing, deliberate immission or accidental of alien kind. The immission of foreign kind involves many problems: genetic pollution, direct or indirect competition with home kind. Case more eclatantes that of the silurus glanis, voracious raider coming from the great rivers of central and oriental Europe has almost colonized all rivers course of northern Italy. In the great ones rivers as the Danubio it can reach the 2,5 meters and 300 kgs. of weight, in the Po numerous superior samples have been fished to the quintal. You nourishes of great quantities of ciprinidi as chub, bleaks and triotti. Investigations effected in the province of Rovigo have noticed that this giant is present in every progress of water, it constitutes 27% of the total one of the biomass and it is the kind more represented. The female it deposes every year 20-30.000 eggs for every kg. of weight. «They are at least three the documented cases in the Italian sweet waters in which you/they result damaged and you threaten endemic kind: that of the Rovella and of the Triotto in some basins of center-southern Italy, that of the Gudgeon of brook and Gudgeon padano in some progress of water of central Italy tirrenica, that of the Loose one and of the Nose (Savetta) in Friuli Venezia Julia». All cases in which the first kind has in practice brought next to the disappearance the home kind for direct competition. To her base of these presences «foreigners» the wrong repopulations done for the sporting fishing.
La "Gazzetta del Mezzogiorno"