Pollock Conservation Cooperative Research Center
2008 Awarded Research Projects
Project Title: Fatty acid composition of forage species in the Bering Sea: Variability and its effect on estimating predator diets using quantitative fatty acid signature analysis
Principal Investigator: Alan Springer and Sara Iverson
Award: $51,025 (year 1), $22,064 (year 2), $3,980 (year 3)
Estimated Completion: January 31, 2012
Abstract
Knowing what animals eat is perhaps the single most important requirement for understanding relationships of predators to prey, how food webs, communities, and ecosystems are organized, and why populations fluctuate in abundance over time and space. The most powerful new approach for estimating predator diets in marine ecosystems employs fatty acids (FA), which are passed up the food chain in predictable ways and can be used to quantitatively estimate predator diets at each trophic level. For a given predator, this requires a catalog of the FA composition of all likely prey. The overall efficacy and accuracy of the FA method of diet analysis is well established, yet important questions remain of how potential spatial and temporal variability in FA composition of individual prey species affect diet estimates. Our goal is to evaluate the magnitude of variability among seasons, years, and locations in FA composition of principal forage species supporting seabirds and marine mammals in the Bering Sea. We will build upon our recent studies of diets of seabirds and fur seals using FA, which have not had the resources to investigate these issues, and will fully exploit a large collection of forage species obtained in collaboration with the National Marine Fisheries Service. Products from this study— an extensive catalogue of FA signatures of the principal forage species in the Bering Sea, coupled to assessments of the magnitude of variability in FA and its significance to quantitative diet estimates—will be available to others wishing to employ FA analysis.
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