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,
History of the North Sea it gained significant economic importance in the 1960s as the states on the North Sea coasts began full-scale exploitation of its oil and gas resources. The North Sea continues to be an active trade route. The countries bordering the North Sea all claim the of territorial waters within which they have exclusive fishing rights. Today, the North Sea is more important as a fishery and source of fossil fuel and renewable energy, since territorial expansion of the adjoining countries has ceased. One of the earliest recorded names was "Septentrionalis Oceanus", or "Northern Ocean" which was cited by Pliny. However, the