Evaluating quantitative fatty acid signature analysis (QFASA) in fish using controlled feeding experiments

Accurate diet estimation has long been a challenging issue for researchers investigating predators due to constraints associated with stomach content analyses. Fatty acid signature analysis offers an alternative avenue to study long-term diet trends in consumers. Despite the wealth of experiments involving fatty acids of fish and their diets, few have evaluated quantitative fatty acid signature analysis (QFASA) with fish consumers. To this end we fed juvenile lake trout, round goby, and yellow perch various invertebrate species and back-classified each predator to its respective prey using only fatty acids. Estimates were highly accurate when metabolism of diets was natively accounted for by using fatty acid profiles of predators fed known diets as the “prey library”. While highly accurate results were obtained, accounting for each predator-prey relationship limits the use of QFASA to predators that consume a limited number of species. We call for predator-prey specific knowledge of metabolism before attempting to use fatty acids for quantifying consumer’s diets. Only after adequate incorporation of species metabolism will fatty acids provide an accurate view of individual’s diets when stomach content data are not available or invalid.The accepted manuscript in pdf format is listed with the files at the bottom of this page. The presentation of the authors' names and (or) special characters in the title of the manuscript may differ slightly between what is listed on this page and what is listed in the pdf file of the accepted manuscript; that in the pdf file of the accepted manuscript is what was submitted by the author