Reproduction of zooplankton in relation to initiation of spring phytoplankton bloom in the Barents Sea
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The phytoplankton spring bloom development and zooplankton reproduction were investigated in April 1986 in the central and northern Barents Sea. Different stages of phytoplankton bloom development were found, reflecting differences in water column stability and illumination due to ice melting. Eggs and nauplii of Calanus, Pseudocalanus, Microcalanus and Oithona spp. occurred mostly in the upper 50 m without any pronounced maxima in their vertical distributions. The total numbers of eggs and nauplii of Calanus finmarchicus and C. glacialis tended to be higher at bloom stations than at pre-bloom stations, and also to show a general increase during the investigation period. The start of spawning was estimated to early February and was not influenced by the phytoplankton bloom development. Neither did the developmental state of the copepodite population seem to be influenced by the bloom development. The spawning activity, however, seemed to have a maximum coinciding with the early phase of the bloom development.