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 1999

摘要

Introduction: The Norwegian spring-spawning herring reoccupied the Norwegian Sea as its main feedingarea in the early 1990s, after nearly 25 years of absence. The herring stock is now a typicalstraddling and highly migratory stock, and its migration mute crosses the borders of severalnational EEZs (exclusive economic zones) and international waters. From 1994, aninternational fishery has taken place during summer in the area. The total catch of Norwegianspring spawning herring in the Norwegian Sea and along the Norwegian Coast in 1998exceeded 1,2 million tonnes. Since 1995, the Faroes, Iceland, Norway, and Russia, and since 1997 also the EU, havecoordinated their survey effort on this and other pelagic fish stocks in the Norwegian Sea.The co-ordination of the surveys has strongly enhanced the possibility to assess and describcthe distribution of the pelagic resourccs, and their general biology and behaviour in relation tothe physical and biological environment (Table 1) Based on an ICES recommendation in1948, similar surveys were conducted under the auspices of ICES from 1950 to the late 70's.National surveys were continued after this time. At the 1996 Annual Science Conference, thePelagic Committee recommended that the ICES cooperation should be reintroduced on theplaning and conducting of future surveys on herring and the environment in the NorwegianSea. For the survey efforts to be carried out in 1999, a planing meeting was held in Lysekil inAugust 1998 (Holst et al., 1998), and a series of 10 surveys to be carricd out by Faeroese,Icelandic, Norwegian, Russian, and EU-research vessels in spring and summer 1999 werecoordinated (Table 1). The main objectives of the coordinated surveys were to map thedistribution and migration of the herring and other pelagic fish, to assess their biomass, and tomonitor environmental conditions of the Norwegian Sea and the quantity of available food inthe sea for herring.The 1999 coordinated survey results were evaluated during a meeting in Hamburg in August1999 (Table 1). The limited time available for the analysis allows only for a brief overview ofthe main findings of these surveys with respect to herring distribution and migration,environmental conditions (sea temperature, zooplankton biomass), herring abundance, andblue whiting distribution.