Life history and exploitation of the Norwegian spring spawning herring

Abstract

This paper is a review of the history and exploitation of the Norwegian spring spawning herring stock. In a virgin state the biomass of this stock may have ranged from 15 to 20 million tonnes and it was the most important fish resource in the Northeast Atlantic. The adult stock utilized the rich plankton production along the Polar Front in the Norwegian Sea but spawned during winter on the Norwegian west coast. These spawners formed the basis for the largest fishery in Europe for centuries. The young and adolescent herring are distributed in Norwegian coastal waters and in the Barents Sea where they constitute the most important prey species or many stocks of predators, both of fish , birds and mammals. Due to technical advances the exploitation of the herring increased tremendously in the 1960's and the adult stock was fished out completely in 1970. Some small components of juvenile herring did however survive, and spawned on the traditional spawning grounds in 1973. After spawning the herring did not migrate to the traditional feeding area in the Norwegian Sea, but remained i n Norwegian coastal waters throughout the year. In later years the stock has recovered slowly, but the old traditional migration pattern of herring between the Polar Front area and the Norwegian coast has not yet been retained. It is concluded that the break down of the life cycles of the herring is the prime reason for the recent crisis which has developed in the Barents Sea stocks and fisheries.