Interannual correlation between hemispheric climate and northern Norwegian wintering stocks of two Calanus spp.

Calanus finmarchicus and Calanus hyperboreus were sampled by five replicate Juday net tows from bottom to surface in February and October 1983-2000 in two deep fjord basins with different sill depths. C. finmarchicus was an order more abundant than C. hyperboreus in both fjords. Seasonal stock changes probably expressed the difference between rates of mortality and immigration. The interannual variability in abundance was about an order of magnitude. Only C. finmarchicus was positively correlated with North Atlantic Oscillation, in opposite phase with its abundance in the North Sea, possibly due to changing winds that generated latitudinal shifts in the C. finmarchicus base population of the Northeast Atlantic. However, latitudinal shifts in westerly storm tracks possibly also forced vernal river flow from Norway to regulate the neritic plankton productivity and growth in the population of C. finmarchicus. Positive correlation between Arctic Oscillation and both species may be due to forcing of advected recruitment. Arctic Oscillation possibly also regulated population size in C. hyperboreus.

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".