Prawns are usually found at a depth between 100 and 700 metres but are found both shallower (up to 20 metres) and deeper (down to 900 metres), and they prefer temperatures between 1-6 ºC. The prawn stock is classified according to where it lives. In Norway, prawns are found in fjords, coastal areas, in the North Sea/Skagerrak and in the Barents Sea. In the North Sea, the fishery involves the stock that is found in the Norwegian Trench. Prawns are also found on both sides of the North Atlantic, around Iceland, Jan Mayen and Greenland and along the east coast of Canada.
During the day, the prawn lies on the bottom to rest or feed. At night, it rises in the water column to eat zooplankton. The prawn mostly moves up and down in the water column, but the female can move to shallower water around hatching time.
Northern prawns are hermaphrodites. In other words, they are born as males and change sex. Sex change varies with the various maturation areas. In the North Sea and the strait of Skagerrak, prawns change sex when they are between 1.5–2.5 years old, while in the Barents Sea it happens when they are between 4–7 years old. For prawns in fjords and coastal areas, the sex change occurs at ages 2–6. Sex change increases the further north they live. Prawns can be 15–16 cm and up to 10 years old.
Prawns mate in autumn, and the female prawn carries the spawn under the hind part of its body through the winter. The eggs hatch in the spring. The newly hatched larvae feed on small plankton in the uppermost water layers before they migrate towards the bottom after 2–3 months.
The prawn fishery takes place year round. The prawns in the Barents Sea are fished with large freezer trawlers which process and pack the catch on board. The prawns in the North Sea, the strait of Skagerrak, fjords and coastal areas are fished with small prawn trawlers. The prawns are then primarily cooked on board and sold as fresh, cooked prawns.
The fishing gear used in the prawn fishery is trawls with a minimum mesh size of 35 mm. Sorting grates for fish are required on the prawn trawl. The sorting grate ensures that the majority of fish and small prawns over a certain size are sent out of the trawl again. Studies are also being done on fishing for prawns in Norway with pots, which are common fishing gear in other parts of the world where prawns are fished.
There are several interesting R&D projects under way in the prawn industry. These include a project which is looking at catching, storing and shipping of live prawns to domestic and international markets. These prawns are fished with pots.
Each year, Norwegian and international research provides a basis for advice on sustainable catch in the North-eastern Atlantic Ocean. Norway then conducts negotiations on quotas with other countries that fish for the same stocks. Based on the negotiations, the Norwegian Ministry of Trade, Industry and Fisheries allocates the Norwegian share to Norwegian fishers. It is the authorities who grant a licence to everyone who participates in the industry, and provisions regarding quota allocation and conduct of the fishery are determined through annual regulations for each individual type of fish (control regulations).
Regulations for the various stocks:
Fishing for prawns in the Barents Sea is regulated by the number of permitted fishing days for the prawn boats per calendar year. If a large number of fish fry are present in the area where prawn fishing is being done, the authorities can close the fishing grounds. The prawn stock in the Barents Sea is in good condition, and the fishery is sustainably managed.
For the North Sea and the strait of Skagerrak, quotas are determined each year for prawn fishing. The prawns that are caught must measure at least 7 cm. The Norwegian Institute of Marine Research calculates the size of the prawn stock in the Skagerrak/Norwegian Trough areas. The stock has increased in recent years, and it is considered to be in good condition.
No quotas are set for prawn fishing in coastal areas and fjord areas, but the prawn fishing grounds in these areas can also be closed because of a large number of fish fry in the catches. Coastal and fjord prawns north of 70°N are managed as a part of the Barents Sea stock, while the stock south of 62°N is managed as a part of the North Sea/Skagerrak stock. Between 62°N and 70°N, no equivalent monitoring of the stock is carried out.
The prawn fishery in both the Barents Sea and the North Sea//Skagerrak is certified by the Marine Stewardship Council (MSC). The prawn fishery in the Barents Sea is also certified by KRAV and Friend of the Sea.
Food safety and quality control
The Norwegian seafood industry is subject to stringent requirements in order to ensure food safety. It is a system consisting of several bodies which jointly examine and monitor compliance with the requirements in all stages of the production chain. The bodies which supervise food are the Norwegian Food Safety Authority, the Norwegian National Institute of Nutrition and Seafood Research (NIFES), the Norwegian Directorate of Fisheries and the Norwegian Ministry of Trade, Industry and Fisheries.
A Norwegian Standard (NS 9409:2009) has been defined which must be followed when prawns are supplied with the quality mark Norwegian Prawns.
Prawns are rich in:
- Protein, which builds and maintains the cells in the body.
- Vitamin D, which is necessary for the right calcium balance in the body and which contributes to maintaining and strengthening the skeleton.
- Vitamin B12, which is important for the body's production of new cells, including red blood cells, and which can contribute to preventing anaemia.
- Selenium, an important element in the enzymes that combat harmful chemical processes in the body.
Prawns have a firm flesh and a natural pink colour. The fresh, sweet and slightly salty taste goes well with a wide selection of hot and cold dishes. Prawns can be served by themselves or in salads with various types of sauces or dressings. If the prawns are to be served in hot dishes, they should be added right at the end, so that they stay succulent and tender.