Juvenile Chinook Willamette River Study

Netting juvenile Chinook

Scientists using a beach seine net to capture juvenile Chinook salmon under the Ross Island Bridge on the east bank of the river in Portland, Oregon

In April 2018, a team of field biologists, toxicologists, injury assessment specialists, data managers, and field technicians completed a week in the field as part of a major study to help determine the impacts to Endangered Species Act-listed juvenile Chinook salmon from exposure to contaminants as they out-migrate through the Portland Harbor Superfund site via the Willamette River.

The Portland Harbor Natural Resource Trustee Council identified salmon — specifically, juvenile salmon — as a key species of interest for the damage assessment. Available scientific evidence indicates juvenile Chinook salmon within Portland Harbor have higher tissue levels of contaminants when compared to tissue levels from juvenile Chinook salmon collected upstream of the site. Scientists are concerned that exposures to these compounds may be adversely affecting juvenile Chinook as they move through the system.

The objectives of this study are to update information on the extent to which wild, sub-yearling Willamette River juvenile Chinook stocks are being exposed to contaminants and whether these exposures are impairing growth. If so, the ability of these fish to survive as they enter the lower Columbia River Estuary may be compromised.

The NOAA Office of Response and Restoration (OR&R) Assessment and Restoration Division provided support for technical and logistical planning, field operations, and overall strategic framework in close collaboration with the NOAA Northwest Fisheries Science Center. The Science Center provided the principle investigator (Dr. Jessica Lundin), field and lab experts, and equipment (including a boat). The NOAA Restoration Center provided logistical planning support and field team staff. The NOAA Office of General Counsel provided advanced and real time assistance in negotiating access to private property. The Portland Office of the National Weather Service provided, via their staff river hydrologist, detailed information and assessments of river condition trends. The U.S. Fish and Wildlife Service provided experienced field biologists and boat operators, a boat and a trailer for use as a field lab. And, the U.S. Coast Guard Marine Safety Unit / Portland provided the field team with access to their facility.

So, what comes next? Staff at the Science Center have begun processing and analyzing samples, of which there are many. In addition, all the data captured in the field and generated as a result of the various laboratory analyses will need to be incorporated into OR&R’S data management system, DIVER — which stands for Data Integration Visualization Exploration and Reporting — after undergoing quality assurance and control. Finally, and perhaps most importantly, the data will need to be carefully analyzed and interpreted in order to understand how these fish may be impacted by exposures to contaminants as they pass through the Superfund site. Stay tuned for more as the findings of this study become available.

Measuring juvenile Chinook

A wild juvenile Chinook salmon, 47 mm in length (less than 2 inches) 

Field processing juvenile Chinook salmon.

Dr. Sarah Allen, OR&R Assessment and Restoration Division, and Dr. Jessica Lundin, NWFSC, documenting and field processing juvenile Chinook salmon