Predicting Calanus finmarchicus abundance from a climatic signal

Long-term fluctuations in the abundance of the copepod Calanus finmarchicus in the north-east Atlantic are compared to the North Atlantic Oscillation index over the period 1958-1995. The strong climate-plankton link previously observed is confirmed and a simple linear regression model is constructed with the aim of predicting the abundance of the species several months in advance. For the years 1993-1995 the model predictions are in accordance with observations, but not in 1996 when the abundance of C. finmarchicus fell, although the climatic scenario indicated that a sharp increase should have occurred. The potential causes of this discrepancy are discussed.