Baseline Stations Chinook and coho salmon are sampled at 5 fixed stations to
measure temporal trends in contaminant exposure. Adult
salmon returning to their natal streams are sampled from
terminal "in-river" fisheries for the Nooksack, Skagit,
Duwamish, Nisqually and Deschutes rivers.
Focus Stations To evaluate the effects of artificial rearing practices on the accumulation
of PCBs in coho salmon, contaminant concentrations were compared
for hatchery and delayed release fish as follows: fish hatched,
reared and released directly from the Wallace River Hatchery versus
delayed release fish that were hatched and reared at Wallace River
Hatchery, then held for a period in the South Sound and Agate Pass
net pens prior to release. Returning fish were collected from the
South Sound and Agate Pass mixed stock fisheries (tagged fish) and
from the Wallace River hatchery.
Historic Stations Historically, we sampled chinook and coho salmon from mixed stock
fisheries in Central and Southern Puget Sound. Monitoring on mixed
stocks was discontinued because the origins of the fish were unknown.
We now monitor terminal "in-river" fisheries where the fish origins
are known (see Baseline above).
