MEPS 235:127-134 (2002)  -  doi:10.3354/meps235127

ABSTRACT: The percentage (%) fatty alcohol and fatty acid compositions of the wax esters of large numbers of Stage V and females of Calanus hyperboreus, C. glacialis and C. finmarchicus taken in late August to late September from Arctic waters (Kongsfjord in Svalbard, 78°57¹N, 11°50¹E) are presented. The data reveal that these stages of development of the 3 species can be discriminated on the basis of the % of 22:1n-11 fatty alcohol in their large levels of wax esters, with C. hyperboreus having the highest % followed by C. finmarchicus and then C. glacialis. Equally, C. hyperboreus has the lowest % of 20:1n-9 fatty alcohol in its wax esters with C. finmarchicus having a higher % and C. glacialis the highest %. Relatively minor differences occur in the fatty acid compositions of the wax esters of the 3 species, which consisted principally of 20:1n-9 (15 to 18%) and 22:1n-11 (10 to 15%), together with the diatom-derived fatty acids 16:1n-7 (20 to 23%) and 20:5n-3 (11 to 13%). The flagellate-derived fatty acids, 18:4n-3 (3 to 6%) and 22:6n-3 (1 to 3%), were minor constituents. The fatty acid compositions of the small amounts of polar lipid in the 3 species were indistinguishable with 22:6n-3 (41 to 46%) and 20:5n-3 (22 to 24%) being the major components. We conclude that Stage V and females of the species can be distinguished in autumn on the basis of the different % of 22:1n-11 and 20:1n-9 fatty alcohols in their wax esters and that de novo lipid biosynthetic activity in the copepods increases in the order C. finmarchicus < C. glacialis < C. hyperboreus. We discuss the results in terms of the contributions of fatty acids and fatty alcohols biosynthesised de novo and fatty acids derived from the diet to the copepods¹ lipids, the role of 20:1 and 22:1 fatty alcohols and fatty acids as energy sources, and the possible role of 22:6n-3 in the copepods¹ physiology.

KEY WORDS: Calanus · Arctic · Wax esters · Phospholipids · Acids · Alcohols