Salmon

 Resource Brief - March 2009

Trends of Past Salmon Abundance and Lake Productivity

Recent studies at the Institute of Marine Science, University of Alaska Fairbanks have led to the development of a method to reconstruct long-term changes in salmon abundance from sediment core analysis. This method is based on the observation that salmon strongly impact freshwater environments via input of significant quantities of marine-derived nutrients released from carcasses after spawning. Since 2004, Bruce Finney, University of Alaska-Fairbanks, and SWAN staff have collected and analyzed sediment cores from SWAN lakes. The long-term perspective developed through this project will provide baseline data on these systems, which will help determine how humans have influenced these lake ecosystems, through both local and global activities. Cores from non-salmon systems will help distinguish how factors such as climate change, volcanic eruptions, and geomorphologic change in the absence of salmon, influence freshwater systems. Ultimately, this will provide insight into how future environmental changes may influence freshwater characteristics and salmon productivity in this region, and provide a better understanding of the significance of trends observed in the Network’s future monitoring program. During 2005 cores were taken at Kontrashibuna Lake and in 2006 a final set of cores will be collected from Kijik Lake.

Bruce Finney, University of Alaska-Fairbanks, preparing to collect a lake sediment core.