Quantities of zooplankton and propagation of calanus finmarchius at permanent stations on the norwegian coast and at Spitsbergen, 1959-1962

Abstract

1. Zooplankton has been collected in vertical hauls from 1959 to 1962 at four permanent oceanographic stations along the coast of Norway and one from Spitsbergen. The volumes have been measured and the stage composition of Calanus finmarchicus determined. 2. A delay of occurrence of maxim volume with increasing latitude for the spring maximum of volume is evident, but a similar trend for the secondary maxima could not be demonstrated. The annual richness of zooplankton on the southernmost station (Sognesjøen) was considerably poorer than at the other four stations. At these the amount of zooplankton was of the same order of magnitude. There were large variations in amount of zooplankton from one year to another at all stations, and a general conclusion about the relative richness of the different years could not be made. 3. A significant delay in the time of spawning of Calanus finmarchicus and decreasing number of spawnings with increasing latitude was demonstrated. 4. Maximum of volume occurred about 1½ to 2 months later than the spawning of Calanus finmarchicus when the copepodite stages III and IV in southern Norway and IV and V in northern Norway comprised more than 50% of the stages. A method for prediction of biomass changes based on development-stage distribution of Calanus is suggested.