Fish fauna of the deep subalpine lakes: present status and trends

Large and deep subalpine lakes represent an important resource for biodiversity and ecosystem services such as tourism, water supply for agriculture, drinking and power production, and fishery. In Italy, they constitute more than 80% of the total lacustrine volume and are located in one of the most populated and industrialised areas in Europe which contains approximately 16 million inhabitants. Subalpine lakes have been under significant pressure since the first decades of the XX century. Cultural eutrophication and chemical pollution of industrial origin have impacted or are still impacting lakes and their catchments. Additionally, hydromorphological pressures such as dam construction and water abstraction for agriculture, drinking water and power production have significantly affected lake tributaries and outlets, with further cascading effects on lacustrine biological communities, including fish. Recently, climate change has added to this array of adverse effects on the physical, chemical and biological environments of subalpine lakes and their catchments. Finally, the spread of non-native species in these habitats has recently become significant concern in relation to biodiversity conservation.