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
Ide (fish) the wild in at least one site within New Zealand. Ide occurs in schools in the clear pools of larger rivers, ponds, and lakes but they may move to deeper waters during the winter before moving into shallow freshwater to spawn in the spring. The species is also found in the Baltic Sea, which has a lower salinity than most seas and in Sweden the fish spent the first year of their lives in rivers before joining the more mature fish as they migrated downstream into the Baltic Sea during the summer months. The fish then returned to the rivers