Abundance, feeding and reproduction of Calanus finmarchicus in the Irminger Sea and on the northern Mid-Atlantic Ridge in June

Abstract

Abstract Measurements of hydrography, chlorophyll a, abundance, egg production rates and gut fluorescence of Calanus finmarchicus were made on the northern Mid-Atlantic Ridge, along a north–south transect extending from Iceland to the Azores (∼60–44°N, 25–35°W) in June 2004. In addition, similar data were sampled in the Irminger Sea and on the Reykjanes Ridge in June 2003. The results show marked differences in abundance, phytoplankton ingestion rates and egg production rates from north to south. C. finmarchicus was most abundant in the central Irminger Sea (∼80,000–160,000 individuals m−2, 0–100 m), with abundance declining drastically (