Testing Fatty Acid Based Diet Estimation Models using Diets Composed of Natural Prey Items

We created diets by mixing freeze dried bloodworms, daphnia, and shrimp as well as diets of each prey item by itself and fed them to juvenile lake trout. While the seven diet treatments were visible with both unconstrained (nMDS) and constrained (LDA) visualizations of lake trout fatty acid profiles at weeks 4, 8, and 12, quantitative models such as FASTAR, mixSIAR, and QFASA all returned diet estimates with errors ranging from 7 - 35% per diet item per fish.

It is difficult to prescribe if the high error rates are due to malnutrition, genetics, or other un-accounted for variables in the dataset but we do note that greater accuracy did not correlate with length or mass gained by individual fish nor their lipid contents. Excel file includes: 1)Metadata on experimental setup as well as fatty acid quantification, 2) data on the survival of fish in each treatment, 3) fatty acids expressed in milligram form, and 4) fatty acids expressed as proportions of the total fatty acids quantified.