Year of grant:
Náttúra og -tilfeingi
Herring-zooplankton interactions in the southern Norwegian Sea.
Høgni Hammershaimb Debes
Dr. Jan Arge Jacobsen, Faroese Fisheries Laboratory
Dr. Eilif Gaard, Faroese Fisheries Laboratory
Original: 1.3.2007 - 28.2.2009
Final: 1.3.2007 - 28.2.2009
Grant from the FRC in DKK:
The objective with the project is to describe the interactions between Norwegian spring spawning herring and its food in the area north of the Faroe Islands, and to evaluate the effect of possible climatic changes on it.
The area north of the Faroe Islands is characterized by two different water masses (one cold and one warm) and the front, named the Iceland-Faroe Front, made by the meeting of these water masses. This is a productive area and enormous amounts of different commercial important pelagic fish stocks migrate to and through this area in search of food. One is the Norwegian spring spawning herring. It spawns along the Norwegian coast nearly during spring and then migrates out into the Norwegian Sea to feed. The past years it has been observed in large amounts in this productive area to the north and northeast of the Faroe Islands during spring and summer, where it predates on zooplankton. It is therefore of great interest, both scientifically and economically, to obtain and increase our knowledge of the connection between production, behaviour, and distribution of the herring, and its food in the area and how it will respond to possible climatic changes.
The project will describe seasonal variations in the main food of herring, the copepod Calanus finmarchicus, both horizontally and vertically, and evaluate and compare this information with the gut content of the herring and its distribution and growth.
The project “Herring-zooplankton interactions in the southern Norwegian Sea” is now finished and preliminary results show that large amounts of herring and its main food source were observed in Faroese waters in May 2007 and 2008.
The main research period was in early May 2007. Results from this cruise showed that the main area for herring distribution was north of the Faroes close to the Icelandic border. However, herring was also observed in fairly large amounts in the south-eastern part of the research area northeast of the Faroes.
The results also show that the main food for herring during this season of the year was adult stages of the oceanic copepod Calanus finmarchicus. Adult C. finmarchicus were present in the whole research area with slightly higher abundances to the north of the Iceland-Faroe Front. On the other hand were younger stages of C. finmarchicus much more abundant in the area south of the front.
Primary production was highest in the Iceland-Faroe Front. This was also the area with most phytoplankton in the C. finmarchicus stomachs.
Future plans are to collect data in the area for the next 1-2 years before publishing the results in peer-reviewed scientific papers.