Examining the use of lipid analysis as an indicator of fish habitat condition and overwinter survival of chinook salmon in large rivers of central British Columbia

Lipid and triglyceride levels have the potential to be indicators of the status of individuals and populations of fish because they may affect overwinter survival and energy allocation strategies. Identification of (1) seasonal lipid levels in juvenile fish, and (2) the relationship between fish lipid levels and fish habitat may provide managers with a tool for monitoring the quality of fish habitat in rivers. I assessed seasonal and spatial variation in lipid and triglyceride levels for young-of-the-year stream-type chilnook salmon (Oncorhynchus tshawytscha) throughout central British Columbia, Canada. I found triglyceride levels were highest in fish from the Bridge River, a flow-regulated river, with maximum levels occurring in November. I related triglyceride levels to environmental variables, and found a significant positive relationship between triglyceride levels and food availability. My research supports the potential for using triglyceride analysis as an evaluative tool in freshwater monitoring programs.