The contaminants in Pacific herring indicator tracks the concentration of PCBs and PBDEs in herring whole bodies. The levels of these persistent organic pollutants (POPs) in herring signal harmful concentrations in this species, but also the extent of contamination in the pelagic food web. POPs threaten the health of herring and other forage fish, the health of the fish, wildlife and humans who consume them, and the overall productivity of the pelagic habitat.

• PCB and PBDE concentrations continue to exceed adverse fish health effects thresholds in Pacific herring samples from two of the five monitored stocks (Port Orchard/Madison and Squaxin) but not for herring collected from three less contaminated stocks (Quilcene/Dabob Bay, Semiahmoo Bay and Cherry Point). Overall, PCB and PBDE concentrations are decreasing (see Interpretation of Results for more details). Thus, we determine this indicator is BELOW TARGET but GETTING BETTER.
• PCB and PBDE concentrations that exceed the adverse fish health effects thresholds may impair herring growth, health and subsequent survival, limiting food supply to predators that rely on them.
• PCBs and PBDEs in herring are transferred up the food chain to their predators, including Chinook salmon, and ultimately to Southern Resident killer whales (SRKW) who feed on salmon. This results in high enough PCB levels in both Chinook salmon and SRKW to negatively impact their recovery.