posted on 2021-07-12, 23:44authored byJessica
I. Lundin, Paul M. Chittaro, Gina M. Ylitalo, John W. Kern, David R. Kuligowski, Sean Y. Sol, Keri A. Baugh, Daryle T. Boyd, Mary C. Baker, Robert M. Neely, Kennith G. King, Nathaniel L. Scholz
The industrial waterway
in Portland Harbor, Oregon, is a migration
corridor for a distinct population segment of Chinook Salmon (Upper
Willamette River) currently protected by the U.S. Endangered Species
Act. Juveniles are exposed to a suite of contaminants during outmigration
including polycyclic aromatic hydrocarbons (PAHs), polychlorinated
biphenyls (PCBs), and dichlorodiphenyltrichloroethanes. We collected
natural origin subyearling Chinook salmon from sites in and around
the industrial harbor to evaluate growth (otolith microstructural
analysis) in relation to measured chemical concentrations in tissue.
A reduced growth rate was associated with higher tissue contaminant
concentrations, particularly mixtures represented by PAHs and certain
PCBs, which were elevated in juvenile Chinook collected throughout
sites within Portland Harbor relative to those captured upstream.
First-year growth is an established predictor of individual survival
and eventual reproductive success in Chinook salmon. Therefore, our
results indicate that legacy pollution may be limiting the population
abundance of threatened Willamette River Chinook salmon, and future
habitat remediation or restoration actions may benefit ongoing species
recovery efforts.