Lake environment

The lake basin is probably one of the most important components of the area’s ecosystem because pure waters, clear and icy, make it an ideal habitat for many species of animals and plants. The sea bottom is covered by a lot of seaweed as Cloroficee and Dyatomee; but the main species are represented by Angiosperme. Several fishes are renowned as the eels, the crayfish, the small trout called "Carpione of Fibreno" and the rare macrostigma trout. The "Carpione of Fibreno " (Salmo fibreni, Zerunian & Gandolfi 1990) is an endemic species whose distribution is limited to this lake and she alive mainly in the cavity of the rocks from that goes out alone of night and in the coldest months for reproducing itself. She belongs to the family Salmonidae, and is a shy and benthopelagic species that hides in cavities between rocks or in cover created by deep vegetation; reproduction takes place from December to January. This species is not listed in the Red Data Book of IUCN (International Union for the Conservation of Nature), but it is very likely to be an endangered species given the history of species of endemic trout that have been replaced, or genetically damaged, by hybridation following the introduction of other species of trout. A legend tells that it is nourished some restrained gold in the sand of the lake to maintain unbroken the fine amber-colored color of its skin. It is an endemic species and for this cause it was included in the protected species from 1986.
Another especially well-known species is the macrostigma trout (Salmo trutta macrostigma, Duméril 1855), ancestor of all of the specimens present today in the Mediterranean basin; unlike of the other Italian localities, from which now almost is disappeared, she seems to have found here its ideal habitat. She also was submitted to protection, introduced in the red book of the WWF (World Wildlife Found) and protected from the directive 92/43 EU, which consider it as a "species of priority interest public whose preservation asks for the designation of special zones of protection". The Posta Fibreno population of this species is important, since it is one of the few still existing in central Italy. Trota macrostigma reproduces between February and March and grows to a larger size than Carpione of Fibreno. Studies conducted on this matter have theorized that one of the main factors that accounts for the coexistence of two species of trout in a confined habitat is their different period of reproduction.
Recently, the harmony that existed between the lake and its many species of birds has been disturbed by the accidental introduction of an exotic species called the Coypu (Myocastor coypus), a mammal belonging to the order of Rodentia.