An hypothesis concerning the space-time succession of Calanus finmarchicus in the northern North Sea

An hypothesis which explains the space-time succession of Calanus finmarchicus in northern European waters is presented. The hypothesis is based on observations of the regional abundance and behaviour of C. finmarchicus during its life cycle, and on knowledge of the water mass distribution and general circulation of the North Sea and of the adjacent continental slope margins. The basis for the hypothesis is supported by modelling of the general features of the continental slope dynamics. An integral part of the hypothesis is the existence of a poleward-flowing eastern boundary jet at the north-west European shelf edge and a counterflow at depth. The final conclusion is that the succession of C. finmarchicus can be explained by a series of space-time cycles along the continental slope of the North Sea and the southern Norwegian Sea in which an intricate combination of hydrodynamics and the migration behaviour of this species play an important role.