CHEMICAL AND CARBON ISOTOPIC COMPOSITION OF FATTY ADDS IN ADIPOSE-TISSUE AS INDICATORS OF DIETARY HISTORY IN WILD ARCTIC FOXES (ALOPEX-LAGOPUS) ON SVALBARD

The chemical and carbon isotope compositions of triacylglycerol fatty acids were analysed in samples from two or more adipose depots dissect ed from adult and subadult arctic foxes collected between November 199 1 and March 1992 in four different areas of Spitsbergen in the Svalbar d archipelago (latitude 78 degrees 5' to 79 degrees 50' N). Site-speci fic differences were minor but there were large and consistent differe nces in the fatty acid composition of the storage lipids of foxes caug ht in the same areas, suggesting that residents of contiguous territor ies may have had quite different diets. The adipose tissue of adult fo xes caught in Austfjordneset, an area where reindeer are rare, contain ed a much greater proportion of unsaturated fatty acids, suggesting th at these animals were feeding mainly in the marine ecosystem, probably on seabirds and/or fish in summer and the remains of polar bear kills in winter. Measurements of the relative abundance of the carbon isoto pes C-12 and C-13 in individual fatty acids show that palmitoleic acid (C16:1) in storage triacylglycerols originates from the marine food c hain, probably together with most other unsaturated lipids, but that t he foxes obtain oleic acid (C18:1), and probably most saturated fatty acids, from either terrestrial or marine sources.