Fishing in the Nordic economic zone north of 62ºN is heavily regulated. All fishing vessels over 20 meter must have a concession for prawn fishing. The tool for fishing used in the prawn fishery is trawl equipped with a separating grid. This grid prevents small prawns and fish fry from getting caught in the trawl. The Institute of Marine Research continuously monitors marine resources and the environment to ensure sustainable harvesting of Norwegian prawns. The Directorate of Fisheries and the Norwegian Coast Guard have the authority to close prawn fishing in areas where the proportion of small prawns and by-catch exceeds specified limits. Prawn fishing in the Barents Sea is certified as sustainable fishing by the Marine Stewardship Council.