There are a number of herring stocks in Norwegian waters. North Sea herring is a schooling fish found in the North Sea, Skagerrak and Kattegat. This means that it lives further south than Norwegian spring-spawning herring, and it mainly spawns in autumn. Herring can reach a length of up to 40 centimetres and a weight of 500 grams. Its life span is up to 25 years. There is less fishing for North Sea herring than Norwegian spring-spawning herring, which is the biggest herring stock in Norwegian waters.
Herring fishing in the North Sea and Skagerrak mainly takes place in the summer and autumn. Herring is sold as fresh and frozen fillets and as whole fish. There are many types of processed herring, e.g. salted, hot smoked, cold smoked and various types of marinated herring to be eaten with bread.
North Sea herring is a good source of vitamin D. It is also rich in marine omega-3, but its fat content varies with the seasons.
Content of undesirable substances
North Sea herring generally contains low levels of both heavy metals and organic environmental toxins, and it is safe to eat. The levels of organic environmental toxins in North Sea herring are slightly lower in the North Sea than in Skagerrak.
NIFES has conducted a thorough investigation of North Sea herring from summer 2009 to autumn 2010, where approximately 1000 samples were taken mainly in the North Sea. Some samples were also taken from Skagerrak, west of Shetland and in the English Channel.
As a follow up, samples are taken of 25 individual fish from two positions in Skagerrak. In the North Sea, samples are taken of 25 individual fish from two positions every third year.