USING PREDATOR BONES TO DETERMINE TROPHIC DYNAMICS 

Reconstructing a Century of Coastal Productivity and Trophic Dynamics from Bone Specimens

Researchers use isotopic analysis to study changes in the place of Salish Sea seals within the food web.

Principal Investigator

Gordon Holtgrieve, University of Washington, School of Aquatic and Fishery Sciences

Co-Principal Investigators

Eric Ward, Northwest Fisheries Science Center

Christopher Harvey, Northwest Fisheries Science Center

Project

As part of the California Current Large Marine Ecosystem, Washington coastal waters host some of the world’s most productive fisheries. Fishermen and planners are interested in understanding what influences this regional productivity. The project will provide an 80-year-plus perspective on food web dynamics involving harbor seals, comparing changing predator and prey abundances with shifting ocean productivity regimes. Using a novel technique called “compound-specific isotope analyses” to examine nitrogen isotope ratios in archived seal bone collagen, researchers will assess the role of increasing marine predator populations on coastal ecosystems.