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Fatty Acid Profile and Lipid Class Analysis for Estimating Diet Composition and Quality at Different Trophic Levels Ron A. Heintz and Marie L. Larsen We examined spatial and temporal variation in the lipid and fatty acid content of young-of-the-year (YOY) Pacific sand lance (Ammodytes hexapterus) and spatial variation in YOY Pacific herring (Clupea pallasi). Spatial variation of YOY herring and sand lance was evaluated by collecting fish from six locations in Prince William Sound (PWS), Alaska between July 15 and August 2, 1997. This allowed us to remove the effects of season and age as alternative sources of variation. Seasonal variation in the lipid content of age-0 and age-1 sand lance was examined by sampling sand lance periodically from the same location in Kachemak Bay, Alaska between May 22, and August 28, 1998.. Lipid and fatty acid content of herring and sand lance varied between sites. Fish from sites in southwestern PWS generally had the highest lipid contents; size adjusted contents for herring ranged between 8% and 10% lipid (dry weight) and for sand lance ranged between 9% and 16%. Spatial differences in fatty acid composition, as determined by discriminant function analysis, were consistent with differences observed in lipid content. Fatty acid compositions of sand lance from southwestern PWS were more similar to each other than to those of sand lance from central PWS. Temporal variation in lipid content of age-0 and age-1 sand lance followed different patterns. Lipid content of age-0 sand lance declined by 50% between June 1 and July 9. In contrast, age-1 and lance had increased their lipid content during the same period. These differences in pattern are believed to result from differing energy allocation strategies that relate to the differences in their life histories. View Poster
See also Habitat Investigations: Fatty Acid Analysis 
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