History of the North Sea great herring fishing industry resulting in Scotland becoming a European leader in that industry. During the First Schleswig War (1848–51), the Crimean War (1854–56) and the Second Schleswig War (1864), belligerents took steps to reduce or eliminate commerce in the North Sea by their enemies. In the first Schleswig War, Denmark was able to halt maritime commerce by Germany in the North Sea and in the second, imposed tolls on ships crossing through the Danish straits between the Baltic and North Seas. The Crimean War saw British and French expeditions sent into the Baltic to prevent Russian ships' egress into
Migration of marine species in the Northern Atlantic Ocean as black carbon also catalyze the warming effect as they are unreflective and absorb energy from the sun supplementing greenhouse gases in the warming effect. These combined factors are warming the Earth's land as well as the oceans. Many fish species possess a certain range of water temperature that they are able to tolerate which is causing species to migrate to different areas where the water temperature is livable. The warming of the Atlantic Ocean is causing many fish species to shift north towards once cooler waters so they can live within their temperature range. Tropical species are being found