Heavy Metal Salmon: Sub-Lethal Toxicity in the Skeena

Heavy metals are common pollutants of aquatic systems, often associated with human activities. Hard-rock mining, agriculture, urbanization, and industrialization have enabled the release of significant quantities of heavy metals to aquatic ecosystems, sometimes with profound ecological harm.

All of the metals that were examined can negatively impact salmonids to some degree at concentrations below the levels known to cause lethality. Sub-lethal concentrations can alter behaviours related to predator avoidance, foraging, migration, and social interactions, and can cause the physical impairment associated with growth and development, swimming efficiency, and immune system responses.