Regional differences in fatty acid composition in common minke whales (Balaenoptera acutorostrata) from the North Atlantic

Résumé

Variation in fatty acid (FA) composition of blubber collected in 1998 from 170 common minke whales (Balaenoptera acutorostrata) was used to study population structure in the North Atlantic. Samples from seven IWC management units were analysed: West Greenland (‘WG’, n = 69); East Greenland (‘CG’, n = 3); Jan Mayen (‘CM’, n = 24); Svalbard (‘ES’, n = 16); the Barents Sea (‘EB’, n = 30); Vestfjorden/Lofoten (‘EC’, n = 7); and the North Sea (‘EN’, n = 21). FA analyses were conducted on both deep and superficial blubber with a one-step extraction and esterification method followed by gas-chromatography. The 43 FAs identified comprised 93-99% of total FAs. CART and MANOVA analyses on FA signatures in both blubber sections suggested a ‘3-geographic Regions model’ where the regions were Greenland (WG, CG), the Northeast Atlantic (CM, ES, EB, EC) and the North Sea (EN). This is in general agreement with a genetic study on the same samples and suggests that differences in FA signatures can be used for studying population structure in minke whales. Potential variation in FA signatures caused by internal and environmental factors needs to be better understood. It is recommended that future studies of blubber FA signatures in minke whales include samples from their entire North Atlantic range (including Canadian and Icelandic waters). Samples should be collected from a pre-specified body site to rule out possible internal variation and during a narrow time-window in the same year to rule out seasonal exchange between areas.