Fauna of Europe of the Baltic Sea has led to the evolution of many slightly divergent species, such as the Baltic Sea herring, which is a smaller variant of the Atlantic herring. The most frequent benthic species are "Saduria entomon" and "Monoporeia affinis", which is originally a freshwater species. A great part of its bottom is anoxic and without animal life. The Baltic Sea and North Sea are also home to a variety of marine mammals (common seals, grey seals). Europe contains several important freshwater ecoregions, including the heavily developed rivers of Europe, the rivers of Russia, which flow into the Arctic, Baltic,
European sea sturgeon 19th century, these fish were used extensively to produce caviar, but have been a protected species in Europe since 1982. European sea sturgeon The European sea sturgeon ("Acipenser sturio"), also known as the Atlantic sturgeon or common sturgeon, is a species of sturgeon previously found on most coasts of Europe. It is anadromous and breeds in rivers. It is currently a critically endangered species. Although the name Baltic sturgeon sometimes has been used, it has now been established that sturgeon of the Baltic region are "A. oxyrinchus", a species otherwise restricted to the Atlantic coast of North America. The wedge-shaped