Report on surveys of the distribution, abundance and migrations of the Norwegian spring-spawning herring, other pelagic fish and the environment of the Norwegian Sea and adjacent waters in late winter, spring and summer of 1997

Abstract

The distribution and migrations of Norwegian spring spawning herring in the Norwegian Sea in the spring and summer of 1997 were mapped during 11 coordinated surveys carried out by Faroese, Icelandic, Norwegian, Russian and EU research vessels. After spawning on the banks off the Norwegian coast in February-March, the spent herring migrated out into the Norwegian Sea, and were recorded in international waters in April. In May, the younger part of the spawning stock was distributed in small schools or scattered layers at 25 - 100 m depth over wide areas in the central Norwegian Sea. Older and larger herring formed large schools, generally at 250 - 400 m depth, near the cold front along the eastern border of the Icelandic EEZ ( exclusive economic zone ). The total abundance of herring in the Norwegian Sea was estimated to be about 45 billion individuals or about 9 million tonnes in May.