In the marine environment, fatty acids are found with a variety of structures and many organisms have unique fatty acid profiles in their fat storage tissues. These profiles or signatures resemble the fatty acid profiles of the diets of the consumer. One aspect of our work in this area is currently focused on using these fatty acid profiles to recognize differences in feeding ecology in competing forage fish species in the Gulf of Alaska. We are also using controlled feeding studies to understand the ways in which consumers subtly modify the fatty acid profiles of their prey so that we can better estimate recent diets using fatty acid signatures. Last, in collaboration with Jeff Bromaglin at USGS, we are investigating methods to improve the quantitative fatty acid signature analysis (QFASA) model used to estimate predator diets.
More recently, we have begun to investigate the stable carbon isotopes of fatty acids as specific markers of diets, using compound-specific isotope analysis. While concentrations of fatty acids will change from prey to predator, changing the fatty acid profile, we expect very little modification in the isotopic signature of fatty acids, particularly essential fatty acids. Using Atlantic pollock as a model species, we are currently investigating the fractionation of dietary fatty acids during incorporation into fish tissues.
Bromaghin, J.F., Rode, K.D., Budge, S.M. and Thiemann, G.W. 2015. Distance measures and optimization spaces in quantitative fatty acid signature analysis. Ecology and Evolution 5: 1249-1262. DOI: 10.1002/ece3.1429
Wang, S.W., Budge, S.M., Iken, K., Gradinger, R.R., Springer, A.M. and Wooller, M.J. 2014. Importance of sympagic production to Bering Sea zooplankton as revealed from fatty acid-carbon stable isotope analyses. Marine Ecology Progress Series. doi: 10.3354/meps11076.
Graham, C., Wang, S.W., Oxtoby, L., Budge, S., Wooller, M.J. 2014. Sourcing fatty acids to juvenile polar cod (Boreogadus saida) in the Beaufort Sea using compound-specific stable carbon isotope analyses. Polar Biology 37: 697-705.
Rode, K. D., Regehr, E.V., Douglas, D.C., Durner, G., Derocher, A.E., Thiemann, G.W. and Budge, S.M. 2014. Variation in the response of an Arctic top predator experiencing habitat loss: feeding and reproductive ecology of two polar bear populations. Global Change Biology 20: 76-88. 10.1111/gcb.12339
Wang, S.W., Budge, S.M., Gradinger, R.R., Iken, K., Wooller, M.J. 2014. Fatty acid and stable isotope characteristics of sea ice and pelagic particulate organic matter in the Bering Sea: tools for estimating sea ice algal contribution to Arctic food web production. Oecologia 174: 699-712. 10.1007/s00442-013-2832-3
Budge, S.M., Penney, S.N., Lall, S.P. 2012. Estimating diets of Atlantic salmon (Salmo salar) using fatty acid signature analyses; validation with controlled feeding studies. Canadian Journal of Fisheries and Aquatic Science 69-1033-1046.
Budge, S.M., Wang, S.W., Hollmén, T.E. and Wooller, M.J. 2011. Carbon isotopic fractionation in eider adipose tissue varies with fatty acid structure: Implications for trophic studies. Journal of Experimental Biology 214: 3790-3800.
Budge, S.M., Penney, S.N. and Lall, S.P. 2011. Response of tissue lipids to diet variation in Atlantic salmon (Salmo salar): Implications for estimating diets with fatty acid analysis. Journal of Experimental Marine Biology and Ecology 409: 267-274.