Hydrographic conditions in the Norwegian Sea in the 1990s and their influence on plankton status and Atlanto-Scandian herring migrations

On the basis of data from annual summertime oceanographic surveys, conducted by PINRO in the Norwegian Sea, considerable variations in the maritime climate of this region during the 1990s have been identified. The early and later parts ot the 1990s were characterized by significant increases of water temperature of the Norwegian Current comparable to that in the early 1960s and mid-1970s. In the mid-1990s, transgression of cold water from the East Icelandic Current into the central part of the Norwegian Sea was accompanied by an abnormal decline of sea water temperature similar in magnitude to that observed at the end of the 1960s and early 1980s. Alternation of variation of water temperature anomalies in the Norwegian Sea during the 1990s took place against a considerable increase of water temperature in the Northeast Atlantic. The observed variations of climate influenced substantially the status of zooplankton ( Calanus fmmarchicus) and migration pattern of Atlanto-Scandian herring.

Article from Marine Science Symposia Vol. 219 - "Hydrobiological variability in the ICES Area, 1990-1999", symposium held in Edinburgh, 8-10 August 2001. To access  the remaining articles please click on the keyword "MSS Vol. 219".