Fishing industry in Denmark for mackerel fish is also the same on one vessel. Additional sprat quota/sandeel quota may be purchased for Baltic Sea sprat and Norway pout fishing. The type of vessels forming the fishing fleets are; trawlers, gill netters and poundnets (50% in this category but with capacity of less than 5GT mostly gill netter); trawlers and purse seiners of 150 GT. A substantial part of the fleet operate under depths of 24 m. After a few prosperous years for Denmark's fishing industry, figures for 2012 were not so good with profits falling to some DKK 600 million from DKK 900 million
Individual fishing quota the zero-sum game imperative of catching as many fish as possible, knowing that any fish they did not catch would likely be taken by another boat. Commercial fishing evolved from subsistence fishing with no restrictions that would limit or direct the catch. The implicit assumption was that the ocean's bounty was so vast that restrictions were unnecessary. In the 20th century, fisheries such as Atlantic cod and California sardines collapsed, and nations began to limit access to their fishing grounds by boats from other countries, while in parallel, international organizations began to certify that specific species were "threatened", "endangered", etc.