For more information on species & ecosystem science:

Wildlife Science
360-902-2515
wildthing@dfw.wa.gov

Fish Science
360-902-2700
fishpgm@dfw.wa.gov

Habitat Science
360-902-2534
habitatprogram@dfw.wa.gov

 

Marine Toxic Contaminants

Species Monitored: Salmon Species

Coho Salmon (Oncorhynchus kisutch) Chinook Salmon (Oncorhynchus tshawytscha)

Chinook and coho salmon are anadromous species and throughout their lives may be exposed to contaminants in freshwater, estuarine, or marine areas. Although specific migratory patterns of these two species vary, they both spawn in freshwater, live there for 3 to 15 months after emergence as embryos from gravel nests, and then migrate to marine waters. Contaminant concentrations in prey they consume may vary in these habitats. In freshwater, the young salmon consume aquatic insects and crustaceans but as they smolt and enter the estuary they consume a wider variety of invertebrates and larval fish. Adult salmon in marine waters continue to eat invertebrates but consume more epipelagic 1 fish, increasing the likelihood of contaminant biomagnification in their tissues. The amount of time each species or population spends at sea varies widely but for both species the majority of their growth occurs in marine waters before they return to their natal streams to spawn. Short-lived fish like coho and chinook 2 salmon, reflect current environmental conditions in their habitats.

The muscle tissues of adult chinook and coho salmon have a relatively high in fat (lipid) content, thus they may accumulate higher concentrations of contaminants in these tissues. Females may pass lipophilic contaminants to their young along with the lipids used for egg development. Thus, the lipid content of the muscle tissue, gender and the degree of sexual maturity may all affect the accumulation of contaminants in these fish.

PSAMP began sampling coho and chinook salmon in 1990 and now samples fixed locations bi-annually. Click for sampling locations.


  1. For both the coho and chinook salmon collected by the Fish Component, the maximum fish age was 5 years.
  2. Living or feeding on surface waters or at midwater to depths of 200 m.