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,
World Network of Biosphere Reserves in Europe and North America of the World Network of Biosphere Reserves. The list does not include the "Intercontinental Biosphere Reserve of the Mediterranean", a biosphere reserve shared between Morocco and Spain, which has been classified as part of the Arab States region. "See also: " See also Portugal and Spain. See also Romania and Ukraine. World Network of Biosphere Reserves in Europe and North America Under UNESCO’s Man and Biosphere Reserve Programme, there are 302 biosphere reserves recognized as part of the World Network of Biosphere Reserves in Europe and North America (as of April 2016). These are distributed across 36 countries in the