Use of blubber fatty acid profiles to detect inter-annual variations in the diet of grey seals Halichoerus grypus

摘要: Diet, and how it varies in place time, are important factors understanding the interactions between seals fisheries. The grey seal eats a wide variety of prey species varia- tions availability can lead to changes both foraging behaviour diet that could affect ecological impact seals. Since is difficult observe feeding directly, we have used fatty acid profiles blubber indicate their diet. We studied inter-colony inter-annual variations female from 2 Scottish breeding colonies, North Rona (RON) Isle May, over 3 consecutive years 1996 1998. obtained were compared tested using several multivariate statis- tical methods, including new inter-population measure Dfap (a distance based on profiles). There significant differences acids all study. within-colony among for at May but not RON. Individual sampled more than 1 yr tended change similar manner Discriminant analysis provided classifications according year with 84 97% accuracy, was less successful RON 56 74% accuracy. Only 4 out 166 'mis-classified' into wrong or grouping. This suggested shift supported by evidence separate study otoliths faeces.