Science activity

This project will examine how contaminant exposures at different temperatures impact a number of critical physiological functions and the associated genes that maintain salmon fitness. The project will determine the sensitivity of fall‐run Chinook salmon to a mixture of bifenthrin, a pyrethoid pesticide, and triclosan, an antibacterial added to personal care products, at optimal and high temperatures that Chinook salmon encounter during their outmigration through the Sacramento and San Joaquin rivers. The hypothesis is that these stressors will impact salmon predator and disease susceptibility and will interact, such that the cumulative effect on salmon could not be predicted from multiple single exposures. To test the hypothesis, fall‐run Chinook salmon parr will be exposed to sublethal concentrations of bifenthrin, triclosan, and a mixture of bifenthrin and triclosan at different temperatures. The impacts of these exposures on salmon will be assessed with the following endpoints: (1) predator susceptibility through altered response latencies and escape velocities;  (2) disease susceptibility in response to a disease challenge; and (3) differential gene expression by high‐throughput sequencing of the Chinook salmon transcriptome.