Circulation patterns in the North Atlantic and possible impact on population dynamics ofCalanus finmarchicus

Abstract

Abstract Due to advective impact few consistent time-series describing the population development of the copepod C.finmarchicus exist. Quantitatively, the spring generation seems to be the most important, and especially in the northern areas one generation per year seems to prevail. A fecundity of 102-103 eggs female-1 and a sex ratio 1:1 then give a maximal reproductive rate of 3.9-6.2 year-1. This low rate seems to be compensated by low mortality due to effective predator avoidance in terms of diurnal and seasonal vertical migrations. We have calculated that the advective renewal of the habitats of C.finmarchicus in the subpolar gyre and in the Nordic Seas are 0.13 and 0.29 year-1 respectively, while the birth and death rates of C.finmarchicus typically are above 3.9 year-1.This means that the biological rates are likely to dominate over the advective rates in the two ocean areas, and that the C.finmarchicus development is facilitated by local production in both areas. Rough calculations for the Nordic ...