ICES Journal of Marine Science: Journal du Conseil Advance Access originally published online on June 10, 2008
ICES Journal of Marine Science: Journal du Conseil 2008 65(7):1112-1121; doi:10.1093/icesjms/fsn097
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Wax-ester mobilization by female Calanus finmarchicus (Gunnerus) during spring ascendance and advection to the Faroe Shelf
1 Roskilde University, Denmark, and Norwegian College of Fishery Science, University of Tromsø, N-9037 Tromsø, Norway
2 Faroese Fisheries Laboratory, Nóatún 1, PO Box 3051, FO-110 Tórshavn, Faroe Island
3 Department of Environment, Social and Spatial Change, Roskilde University, DK-4000 Roskilde, Denmark
Correspondence to M. L. Madsen: tel: +47 776 45896; fax: +47 776 46020; e-mail: matias.madsen{at}nfh.uit.no.
Madsen, M. L., Gaard, E., and Hansen, B. W. 2008. Wax-ester mobilization by female Calanus finmarchicus (Gunnerus) during spring ascendance and advection to the Faroe Shelf. – ICES Journal of Marine Science, 65: 1112–1121.Time of ascendance and initiation of reproduction in Calanus finmarchicus is closely correlated with the phytoplankton spring bloom. However, significant egg production can take place before the bloom, fuelled by mobilizing stored wax-ester lipids. Calanus finmarchicus from stations on the Faroe Shelf were compared with specimens collected off the shelf. Biological parameters such as gut contents, egg production, developmental stage, and lipid content were determined and correlated with phytoplankton concentration and spatial distribution along two transects in late April 2003 across the shelf northeast and southwest of the Faroe Islands. Grazing by C. finmarchicus on phytoplankton was significantly lower northeast of the Faroe plateau. However, the egg production was generally high for a pre-bloom situation, with significantly higher rates of egg production on the shelf than off it, along both transects. Wax-ester content of female C. finmarchicus was significantly higher and more variable at off-shelf stations than on the shelf (<2 µg female–1). From this, we suggest that off-shelf C. finmarchicus had recently emerged from overwintering depths, in contrast to individuals from stations on the shelf, which had been in the upper water masses for some time. Females (from off-shelf stations) most likely supported the initial egg production from their wax-ester reserves.
Keywords: ascendance, Calanus finmarchicus, copepod, egg production, HPLC–ELSD, lipid mobilization, wax esters
Received 17 August 2007; accepted 26 April 2008; advance access publication 10 June 2008.