The spawning biomass it calculated to be 12.2 million tons in 2010. For 2010 the quota was set to 1.48 million tons.
In 2007 an agreement on quota sharing between the coastal states was signed. Of the total quota, Norway gets 61 per cent, Russia 12.82 per cent, Iceland 14.51, EU 6.51 per cent and the Faroe Islands gets 5.61 per cent. This agreement gives these countries the right to fish their quota in the Norwegian Exclusive Economic Zone. The agreement also has an assurance that the stock will stay at a sustainable level.
Management technical regulations of the fishery
The mean catch since 1950 has been around 650 000 tons, but with large variations due to a stock collapse in the late 1960s.
The herring is caught throughout the year along its migration path along the Norwegian coast and in the Norwegian Sea. The most intensive fisheries take place on the spawning grounds in February and in the wintering areas from September to January. The Norwegian fishery along the Norwegian coast is mainly carried out with purse seine, while the international high seas fishery is mainly a pelagic trawl fishery.
In addition to quota regulations, there are regulations aiming at protecting immature fish with a minimum catch size at 25 cm in the Norwegian fishery.
Known by-catches in the purse seine fishery consist of a small amount of large saithe chasing the herring migrations. The fisheries inspection services can close areas if the intermixture of saithe is too high.
Ecosystem
The Norwegian spring spawning herring is a highly migratory stock that is distributed throughout large parts of the North-East Atlantic during its lifespan. The herring spawns along the Norwegian west coast in February to March. The larvae drift north and northeast to the Norwegian coast and the Barents Sea, where the main areas for immature fish are found. Most of the young herring leave the Barents Sea as three years of age and feed off northern Norway for two years, before recruiting to the spawning stock at 5 years old.
The Norwegian spring spawning herring is a very important species in the ecosystems which it inhabits. It preys on Calanus finmarchicus and is itself an important prey for other species such as cod, saithe and other demersal species, in addition to sea birds and whales. Large numbers of killer whales follow the herring during its migration.
About the fishery
The adult herring have a clockwise annual pattern in the Norwegian Sea. The migration pattern changes over time. At present the herring spawn on the Norwegian coast (mainly between 62º and 71ºN) and feed in the Norwegian Sea. Since 2003, a more southwestern feeding pattern has been observed with increasing amounts of older herring feeding in the waters north of the Faroes and east of Iceland during the early feeding in May to June. As the feeding season progresses, the herring has a northerly migration through the Jan Mayen zone along the polar front zone.
After the feeding season, the herring contracts into the wintering areas in September to October. These areas are unstable and since 1950 the stock has used at least 6 different wintering areas in different periods. During the 1950s and 1960s they were situated east of Iceland and since around 1970 in Norwegian fjords. In 2001–2002 a new wintering area was established off the Norwegian coast between 69º30’N and 72ºN and in 2007/2008 no herring was observed in the fiords in winter. After wintering, the spawning migration starts around mid January.