The Willamette River is a major Pacific Northwest waterway, flowing approximately 187 miles north from Eugene until it joins the Columbia River near Portland. Draining the Willamette Valley, this extensive river system supports a diverse collection of aquatic life. The river’s ecological health is tied to the variety of fish species that reside or migrate through its waters, including iconic migratory fish, popular sport species, and a mix of native and introduced populations.
The Native Migratory Fish
The Willamette River is a historic migration corridor for several species of anadromous salmonids. These fish are born in fresh water, migrate to the ocean to mature, and return to fresh water to spawn. The most recognized of these are Chinook Salmon, Coho Salmon, and Steelhead Trout.
Chinook Salmon are divided into distinct populations based on their migration timing, with both spring and fall runs utilizing the Willamette system. Spring Chinook enter the river as early as April, migrating to cooler upper river tributaries to wait out the summer before spawning. Fall Chinook utilize the lower river and its tributaries for spawning after entering the river in late summer or fall.
Coho Salmon are also present, with recent years showing strong adult returns passing Willamette Falls. These fish typically enter the river in September for a fall fishery and utilize tributaries on the west side of the basin for spawning. Steelhead Trout, which are sea-run Rainbow Trout, feature both winter and summer runs, providing angling opportunities almost year-round in some sections. The Upper Willamette River winter steelhead population is a late-winter migrating group, entering fresh water from late winter to early spring to spawn quickly upon arrival.
Resident Game Fish and Sport Fishing Targets
Beyond the migratory salmonids, the Willamette River holds a variety of large, non-migratory fish frequently targeted by anglers. White Sturgeon is a notable resident species that can live for over 100 years and grow to immense sizes. These large fish are often found in the deeper pools and are managed with strict regulations due to their protected status and slow maturation.
The river and its associated sloughs also offer excellent warm-water fishing for bass species. Smallmouth Bass thrive in the mainstem river’s currents and rocky areas, while Largemouth Bass prefer the warmer, slower-moving backwaters and sloughs with dense vegetation. Both bass species are popular sport fish in the region.
Resident Trout species, primarily Rainbow Trout and Coastal Cutthroat Trout, are common throughout the Willamette and its tributaries. Rainbow Trout populations are maintained through annual stocking in many reservoirs and lakes within the watershed. Native Coastal Cutthroat Trout are found in both the main river and its feeder streams, with the upper river mainstem known for productive trout fishing.
Non-Native and Ecologically Important Species
The Willamette River Basin is home to a significant number of non-native species, which account for nearly half of the total fish species found in the system. Non-native species like Common Carp and various Catfish, including Brown Bullhead, are well-established, often outcompeting native fish for resources and space. The feeding habits of Common Carp can lower water quality.
Other introduced species include sunfish, which are popular with anglers and thrive in the warmer, slower sections of the river system:
- Black Crappie
- White Crappie
- Bluegill
- Yellow Perch
Critically important native species not typically targeted by sport fishers also inhabit the river, such as the Pacific Lamprey and various native Suckers. Pacific Lamprey, an ancient sea-run fish, is culturally significant to Native Americans and is a key part of the river’s food web.
Consumption Safety and Health Advisories
Consumption safety is a primary concern for fish caught in the Willamette, particularly in the lower river section. Due to a history of industrial contamination, resident fish can accumulate toxins such as Polychlorinated Biphenyls (PCBs) and mercury in their tissues. PCBs are known to interfere with normal brain development in children.
The Oregon Health Authority (OHA) issues specific advisories with meal recommendations to help the public safely enjoy eating fish while minimizing exposure to these contaminants. General advice for the Willamette River recommends limiting consumption of resident species like carp, bass, and catfish to no more than four meals per month. For the Lower Willamette, especially the Portland Harbor area, advisories are often more restrictive, recommending zero meals per month for high-contaminant fish like Carp and Brown Bullhead.
Toxins like PCBs tend to accumulate in the fat and skin of the fish. Cleaning practices such as removing the skin, fat, and organs before cooking can reduce exposure. Migratory fish like salmon and steelhead are generally considered a healthy choice because they spend a limited amount of time in the contaminated sections of the river, thus accumulating far fewer localized contaminants. Mercury, however, cannot be removed through cooking and cleaning methods.