Fisheries in the Barents Sea

The following information is taken from
the Joint PINRO/IMR report on the state of the Barents Sea ecosystem 2006
Stiansen, J.E and A.A. Filin (editors)

Abstracted by J. Overland, NOAA, Pacific Marine Environmental Laboratory

The Barents Sea, north of the Scandinavian Peninsula is shown, with the prevailing warm and cold current directions, in Figure 1. Temperature in the Barents Sea has been above normal in recent years, and is currently close to an all-time high, rivaling temperatures of 1937-1938, for the periods where observations are available.

Figure 1. The main features of the circulation and bathymetry of the Barents Sea. From PINRO/IMR report.		Figure 2. Mean annual temperature (a) and salinity (b) anomalies in the 0-200 m of the Kola section in 1951-2006. 1 – coastal waters, 2 – the offshore current. From PINRO/IMR report.

Ocean temperature history for the Kola section, directly north of the Scandinavian Peninsula, averaged over 0-200 m depth, shows temperatures of 1 °C above the long term mean (Figure 2). Although this increase may not seem very large, it has the potential to cause significant changes in the ecosystem. For some of the species found in the Barents Sea, recent temperature conditions are probably close to the limit of what they can adapt to, and even a small temperature change may lead to a northward increase of their distribution area. Changes in distribution of species could also cause changes in species overlap and hence predator-prey interactions.

Figure 3. Anomalies of mean monthly ice extent in the Barents Sea in 1982-2006. A blue line shows monthly values, the red one – 11-month moving average values (Anon., 2007). From PINRO/IMR report.

Temperature is not the only relevant factor in this context. The reasons for increases in temperature may be an increased inflow of Atlantic water, or a higher temperature of the water flowing into the Barents Sea. For example, during the winter of 2006, the volume transport of Atlantic Water into the Barents Sea was the highest recorded since the observations started in 1997. Increased inflow leads to increased abundance of nutrients and planktonic organisms, which may enhance growth and survival for the fish species. The winter ice cover in 2006 was the lowest observed since 1970 (Figure 3).

The abundance of cod (Figure 4, blue area) appears to be stable in recent years and warmer temperatures are assumed to be favorable for this species. Caplin (Figure 5, blue area) are at historically low levels and, as a more cold water species, are expected to move north and east. Complicated relationships between cod, capelin and euphausiids (small shrimp) have been demonstrated. Predation on euphausiids by cod decreased the food supply for capelin and reduced the capelin feeding and possibilities for stock recovery. At the same time predation on euphausiids by capelin reduces the food supply for both adult and juvenile cod. Thus both climate change and the internal species dynamics of the ecosystem, as well as fishing pressure, impact future fishing conditions.

Figure 4. Northeast Arctic cod, development of spawning stock biomass (red area), total stock biomass (age 3 and older, blue area) and landings (columns). From PINRO/IMR report.		Figure 5. Barents Sea capelin. Total stock (blue area) and maturing component (red area) during autumn, and total landings (columns), 1973-2006. From PINRO/IMR report.

References

Stiansen, J.E and A.A. Filin (editors), Joint PINRO/IMR report on the state of the Barents Sea ecosystem 2006, with expected situation and considerations for management. IMR/PINRO Joint Report Series No. 2/2007. ISSN 1502-8828. 209 pp. Contributing authors in alphabetical order: Aglen, N.A. Anisimova, B. Bogstad, S. Boitsov, P. Budgell, P. Dalpadado, A.V. Dolgov, K.V. Drevetnyak, K. Drinkwater, A.A. Filin, H. Gjøsæter, A.A. Grekov, D. Howell, Å. Høines, R. Ingvaldsen, V.A. Ivshin, E. Johannesen, L.L. Jørgensen, A.L. Karsakov, J. Klungsøyr, T. Knutsen, P.A. Liubin, L.J. Naustvoll, K. Nedreaas, I.E. Manushin, M. Mauritzen, S. Mehl, N.V. Muchina, M.A. Novikov, E. Olsen, E.L. Orlova, G. Ottersen, V.K. Ozhigin, A.P. Pedchenko, N.F. Plotitsina, M. Skogen, O.V. Smirnov, K.M. Sokolov, E.K. Stenevik, J.E. Stiansen, J. Sundet, O.V. Titov, S. Tjelmeland, V.B. Zabavnikov, S.V. Ziryanov, N. Øien, B. Ådlandsvik, S. Aanes, A. Yu. Zhilin.

North Pacific Groundfish Stock Assessment and Fishery Evaluation Reports (from NOAA / AFSC)

March 13, 2008

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