724_Final Report.pdf - North Pacific Research Board

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Appendix 1. continued FA Dietary test 14 test 15 test 16 test 17 test 18 (Reduced A) test 19 test 20 41 test 21 (Reduced B) test 22 test 23 test 24 test 25 14:0 16:0 16:1n-7 16:2n-6 X X X X X X X X X X X X X 16:2n-4 X X X X X X X X X X X X X 16:3n-6 X X X X X X X X X X X X X 17:0 16:3n-4 X X X X X X X X X X X X X 16:3n-1 X X X X X X X X X X X X X 16:4n-3 X X X X X X X X X X X X X 16:4n-1 X X X X X X X X X X X X X 18:0 18:1n-9 18:1n-7 18:2n-6 X X X X X X X X X X X X X 18:2n-4 X X X X X X X X X X X X X 18:3n-6 X X X X X X X X X X X X X 18:3n-4 X X X X X X X X X X X 18:3n-3 X X X X X X X X X X X X X 18:3n-1 X X X X X X X X X X X X X 18:4n-3 X X X X X X X X X X X X X 18:4n-1 X X X X X X X X X X X X X 20:1n-11 X X X 20:1n-9 X X X X X X X X X X X X X 20:1n-7 X X X X X X X X X X X X X 20:2n-6 X X X X X X X X X X X X 20:3n-6 X X X X X X X X X X X X X 20:4n-6 X X X X X X X X X X X X X 20:3n-3 X X X X X X X X X 20:4n-3 X X X X X X X X X X X X X 20:5n-3 X X X X X X X X X X X X X 22:1n-11 X X X X 22:1n-9 X X X X X 22:1n-7 X X 22:2n-6 X X X X X X X X 21:5n-3 X 22:4n-6 X X X X X X 22:5n-6 X X X X X X X X X X 22:4n-3 X X X X X X X 22:5n-3 22:6n-3 X X X X X X X X X X X X X
CONCLUSIONS The results from this captive feeding study demonstrated that the greatest influence on the FA composition of eider adipose tissue is diet. For both species of eiders, changes in diet were discriminated using adipose tissue FAs. Captive eider diet items were reliably differentiated from each other using both multivariate DFA and more rigorous QFASA simulations. Our results also demonstrated that the response of adipose tissue FAs in both species of eiders to dietary intake was highly predictable. Relative dietary percentages of these five diet items were accurately quantified by QFASA when those percentages had been constant for 10 weeks. Three weeks after a shift between diets with very distinct FA profiles, the shift was clearly reflected in tissue FA but the estimated dietary percentages were lower from the true percentages in diet, reflecting an integration of previous diet in the estimations and confirming that turnover was not complete within the 21-29 d study periods. Most dietary subsets used in QFASA yielded very similar estimates of dietary percentages, although one subset appreciably underestimated the percentages of Mazuri feed and krill and overestimated the percentage for mussels. Comparison of results for a suite of dietary subsets should identify such problems. CCs for the two eider species fed a diet of 88% Mazuri with supplements of krill, silversides, and bivalves were very similar and yielded similar results. When CCs for common murre chicks fed entirely Atlantic silversides were applied to eiders in this study, dietary estimates were similar except for slower loss of and more rapid incorporation of FA from silversides. Diet items were correctly classified with 80% - 100% accuracy in the DFA using only 14 out of the 72 FAs identified. The DFA demonstrated that multivariate techniques are an important precursor to using the QFASA model in determining which potential diet items have overlapping FA signatures. In the QFASA simulations, FA profiles of mussels and silversides also had the lowest rate of discrimination from other diet items in the prey library, but were still well identified at a rate of 93% to 98%. The eider biopsies were correctly classified with 97.9% accuracy using only 7 out of the 72 FAs identified in the DFA and showed that there were changes in FA signatures among biopsies and therefore that they reflected changes in diet, which was confirmed later in the QFASA model. Model estimates were strongly influenced by the FA subset and CC set. The Reduced A and B FA subsets were modified from the published Dietary FA subset and provided the best overall diet estimates for spectacled and Steller’s eiders, respectively (Table 2, Fig. 5 in Chapter 1). The Extended Dietary subset and subsets modified from it provided poorer diet estimates. FAs were omitted from the published subsets in order of highest variability observed in CCs, which tended to provide better diet estimates. In contrast, Iverson et al. (2007) removed FAs with large CCs, which produced poorer estimates in the model. However, diets, CCs and bird species differed between studies and likely 42
Page 1 and 2: NORTH PACIFIC RESEARCH BOARD PROJEC
Page 3 and 4: TABLE OF CONTENTS STUDY CHRONOLOGY
Page 5 and 6: snails (Petersen et al. 1998, Lovvo
Page 7 and 8: een employed in eiders to evaluate
Page 9 and 10: CHAPTER 1. Validating quantitative
Page 11 and 12: Abstract Fatty acid (FA) signature
Page 13 and 14: migration, or how the diets of juve
Page 15 and 16: were switched to Diet 3 which consi
Page 17 and 18: 16:1n-7, 18:0, 18:1n-9, 18:1n-7, 18
Page 19 and 20: The diets of captive eiders were es
Page 21 and 22: Calibration coefficients (CCs) and
Page 23 and 24: Discussion The results from this ca
Page 25 and 26: appropriate for estimating a consum
Page 27 and 28: Ideally, captive studies should mim
Page 29 and 30: Acknowledgments Financial support w
Page 31 and 32: Federal Register. 1997. Endangered
Page 33 and 34: Raclot, T., Groscolas, R., and Cher
Page 35 and 36: Table 2. Sum of the squared errors
Page 37 and 38: Figure 5. QFASA estimates using the
Page 39 and 40: Figure 2. 2nd discriminant function
Page 41 and 42: Figure 4. proportion proportion 1.0
Page 43: Appendix 1. Fatty acid (FA) subsets
Page 47 and 48: we incorporated into our calculatio
Page 49 and 50: There is still much work to be done
Page 51 and 52: ACKNOWLEDGEMENTS Funding was provid
Page 53 and 54: Harrison, N.M. 1984. Predation on j
Page 55: APPENDIX A: ASLC Fact Sheet 52

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