These summary statistics and analyses are based on the European freshwater fishes dataset published in November 2011.
Overall, at least 37% of Europe's freshwater fishes are threatened at a continental scale, and 39% are threatened at the EU 27 level. A further 4% of freshwater fishes are considered Near Threatened. This is one of the highest threat levels of any major taxonomic group assessed to date for Europe. The conservation status of Europe's eight sturgeon species is particularly worrying: all but one are Critically Endangered. By comparison, 44% of freshwater molluscs, 23% of amphibians, 19% of reptiles, 15% of mammals and dragonflies, 13% of birds, 9% of butterflies and 7% of aquatic plants are threatened at the European level.
Despite a lack of good trend data for certain countries, the current assessment shows that about 17% of Europe's freshwater fish species have declining populations, whereas only 1% are on the increase, and 6% are considered stable. For the remaining 76%, the current level of knowledge is insufficient to define their population trends.
The highest levels of species diversity are found in the lower parts of the rivers draining into the Black and Caspian Seas. However, a number of species with restricted ranges are also encountered in the Alps, in Great Britain and Ireland, and around the Mediterranean and Black Seas. Most of the threatened species are confined to certain areas in southern Europe.
Most freshwater fishes are in some way affected by pollution of domestic, industrial and agricultural origin. Another primary threat to Europe's freshwater fishes is habitat loss due to over-abstraction of water. Additional major threats are the introduction of alien species, overfishing (particularly in the larger rivers of Eastern Europe) and a massive increase in the construction of dams, blocking migration and altering stream habitats.