TASC Trans Atlantic Study of Calanus

The project aims to stablish the relationship between the physical and biological factors affecting annual recruitment and reproduction of the species. This is an essential step towards predicting the consequences of future climate change.

The following hypotheses were addressed: 1) The interaction between vertical migrations and shelf edge hydrodynamics determines the ability of C. Finmarchicus to seasonally colonise north-east Atlantic ecosystems from overwintering depths in Norwegian Deep Water off the shelf edge. 2) Year-to-year variations in the timing and dynamics of shelf populations are dependent on oceanic and shelf scale forcing. 3) The deep circulation in the Norwegian Sea Basin and overflow into the North Atlantic is responsible for a 'teleconnection' between C. Finmarchicus summer populations in north-east Atlantic rim ecosystems. 4) Latitudinal gradients in abiotic conditions and interactions with predators control large scale differences in overwintering behaviour 5) The large scale demography, life history timing and generation cycle characteristics of C. Finmarchicus are related to the basic physiology of the species in relation to feeding conditions and the pattern of entry to and emergence from diapause.