PROBLEMS CONCERNING THE POPULATION DYNAMICS 



OF THE ATLANTIC HERRING (CLUPEA HARENGUS L.) 



WITH SPECIAL REFERENCE TO THE NORTH SEA 



B. B. Parrish 



Marine Laboratory, Aberdeen 



INTRODUCTION 



For centuries the fisheries for herring (Clupea harengus L.) have contributed 

 a major share of the total fish harvest in European waters. In the years 1950-5, 

 the annual herring yield for all European countries averaged about two 

 million metric tons, which was approximately one-third of the yield of 

 about six million tons of all species. The events in these fisheries are, there- 

 fore, of major importance to the herring industries and the economies of the 

 major fishing nations of Europe, including the United Kingdom. 



The regions from which these harvests are taken in the north-east Atlantic 

 range from the north coast of Iceland and the Barents Sea in the north to the 

 English Channel in the south, and from the west coast of Iceland in the west 

 to the Baltic in the east. However, two areas are of outstanding importance; 

 the west coast of Norway and the North Sea. The first of these is the centre 

 of the Norwegian winter fishery, between January and April, which reached 

 peak yields of over a miUion metric tons in the years 1950-5; the second is 

 the centre of a great international fishery, pursued throughout the year by 

 the herring fleets of Germany, Holland, the United Kingdom, Sweden, 

 Denmark, Belgium, France, Poland and the U.S.S.R., which together 

 produced about three-quarters of a million metric tons annually in the 

 years 1950-5. 



The results of long-term biological investigations of the herring exploited 

 in these regions have established that these two major fisheries are based on 

 different herring 'tribes'. The Norwegian fishery exploits the oceanic 

 'Atlanto-Scandian', spring spawning 'tribe' which has its spawning grounds 

 on the coastal banks along the Norwegian west coast, and its main adult 

 feeding grounds in the deep, oceanic region between Norway and Iceland. 

 The North Sea fishery, on the other hand, is centred principally on a summer- 

 autumn spawning 'tribe' which has its spawning grounds on banks in the 



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