Return of Norwegian spring spawning herring (Clupea harengus L.) to historical spawning grounds off southwestern Norway
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http://hdl.handle.net/11250/104922Utgivelsesdato
1991Metadata
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From the mid-1940s to mid-1960s a northward displacement of
the spawning areas of the Norwegian Spring Spawning Herring
was observed. Further retraction of the population from
traditional feeding and spawning grounds occurred as the stock
collapsed in the late 1960s. The spawning grounds off
southwestern Norway were abandoned after 1959. Ever since,
spawning appears to have been restricted to a few coastal
grounds and offshore banks off mid-Norway, primarily off the
Møre district.
At present, the abundance of the spawning stock remains
comparatively low; 1.5-2 mill. tonnes as compared with 7-10
mill. tonnes in the 1950s. However, in the spawning seasons
from 1989 onwards, spring spawners have again been observed at
the southwestern grounds. The herring at these southern
grounds in 1990 and 1991 were Norwegian Spring Spawners and
utilized traditional spawning sites. The spawning time was
about a month later than in the 1930s but similar to that in
the 1950s. Results of acoustic surveys showed that of the
total spawning stock, 1.5 - 2 % used the southwestern grounds
i 1990 and 1991.