Migration behaviour of herring along the cold front in the Norwegian Sea in April 1997
Original version
This report is not to be cited without prior reference to the authorsAbstract
The behaviour of Norwegian spring spawning herring when migrating to the feeding areas in
the Norwegian Sea in April was mapped by an acoustic survey in 1997. The distribution of
herring was recorded by conventional echo integration, and the swimming behaviour of
selected herring schools was recorded by a high-resolution sonar. Individual schools were
tracked for up to o ne ho ur.
The herring were recorded in an area between 66° and 68° north, 2° east to 3° 30' west. The
western part of the area was influenced by the southbound, cold East Icelandic current which
induced a termal front within the area. Schools far east of the front had a western migration
direction, while schools closer to the front had a southern migration direction. The migration
behaviour of the herring schools seemed to be influenced by the temperature distribution in
the front. The herring were recorded in large dense schools at 200 - 400 m during daytime. At
night the schools rose to surface and scattered or remained as distinct schools.