MEPS 193:201-208 (2000)  -  doi:10.3354/meps193201

Use of blubber fatty acid profiles to distinguish dietary differences between grey seals Halichoerus grypus from two UK breeding colonies

M. J. Walton1,*, R. J. Henderson2, P. P. Pomeroy1

1Sea Mammal Research Unit, University of St Andrews, St Andrews KY16 8LB, Scotland, UK
2Institute of Aquaculture, University of Stirling, Stirling FK9 4LA, Scotland, UK

ABSTRACT: The population structure of grey seals Halichoerus grypus has previously been studied using molecular biological techniques. These works may be complemented by studies of certain ecological factors which play an important role in providing information on habitat usage, dietary behaviour, local migrations, distribution and social structure. One such factor is the fatty acid composition of depot fats, which is strongly influenced by the fatty acid composition found in the prey. To examine the extent to which the fatty acid composition of seal depot fats can be used to distinguish between populations, blubber biopsy samples were obtained from female grey seals at 2 Scottish breeding sites, Rona (n = 23) and the Isle of May (n = 34) and the fatty acid compositions determined by gas chromatography. The patterns obtained were compared using both univariate and multivariate statistical procedures. Fatty acid profiles at the 2 breeding sites could be clearly differentiated, with only 1 seal out of 57 being mis-classified. Thus, on the basis of blubber fatty acid composition, they may be regarded as 2 distinct foraging groups.

KEY WORDS: Fatty acids · Grey seals · Population discrimination

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