How to Identify Salmon in Washington

Coho Salmon are medium-sized, typically 24 to 30 inches long with a streamlined silver body during ocean phase. In rivers, spawning Coho develop a darker red body, dark head, and a distinctive dark stripe along the side. Chinook Salmon are the largest Pacific salmon, reaching 36 to 60 inches, with a deeper body and darker overall appearance even in ocean phase. Spawning Chinook Salmon turn dark red or black with a hooked jaw. Coho are more common in Washington streams and return earlier in the season, often August through October. Chinook are stronger swimmers and target larger rivers.

Chum Salmon are medium-sized, 24 to 35 inches, and in ocean phase appear similar to Coho but are generally stockier with a more blunt head. The key difference is the spawning phase coloration: Chum Salmon develop distinctive vertical bar patterns, red and black vertical stripes on their sides, and may turn nearly black. Their jaw is less hooked than Chinook. Chum Salmon have a preference for short coastal rivers and estuaries and are common throughout Puget Sound and the Olympic Peninsula. They appear in large numbers in October and November. The red and black vertical stripe pattern is unmistakable once spawning begins.

Sockeye Salmon are smaller than Coho and Chinook, typically 24 to 28 inches long. In ocean phase, they appear bright silver with a metallic sheen. The spawning transformation is dramatic: their body turns deep red, the head becomes dark green, and their teeth become sharp and prominent. The red body and dark green head combination is the most reliable field mark for spawning Sockeye. They have a more slender body than Chum and shorter jaws than Chinook. Sockeye are less numerous in Washington than Coho or Chinook but are present in select rivers and may be observed in Lake Union and other Puget Sound locations.

Ocean phase salmon are typically bright silver with minimal coloring, making them difficult to distinguish from trout at a distance. As salmon enter rivers and begin their spawning migration, they stop feeding and begin to change color. This transformation is gradual and varies by species and location. In rivers, Coho turn dark red and black, Chinook become very dark red or black, Chum develop red and black vertical stripes, Sockeye become deep red with dark green heads, and Pink Salmon develop black vertical bars. The progression may take several weeks as the salmon move upstream. Early in the migration, salmon are in transition and may show mixed coloration. Timing of color change corresponds to river location and distance from the ocean.

Yes, early-stage ocean phase salmon can be confused with trout, particularly Rainbow Trout and Coastal Cutthroat Trout, which are also abundant in Washington waters. The key difference is body proportions and head shape. Salmon have a more streamlined, fusiform body and a steeper forehead profile. Trout have a more robust head, smaller mouth, and a generally sturdier build. Trout do not undergo the dramatic color changes that salmon do. In rivers during the spawning season, this confusion is unlikely because salmon are already colored. On the coast or in estuaries, if you observe a large silvery fish with a streamlined shape and no visible parr marks, it is likely a salmon. Count the gill rakers on the first gill arch: salmon have more than 20, while most trout have fewer than 20.

September through November is the peak season for salmon identification in Washington, when spawning Coho, Chum, and Chinook are in rivers. Late August through October captures the start of the run for Coho and some Chinook. November and December are excellent for Chum Salmon, which peak during fall rains. Pink Salmon runs occur in odd-numbered years and typically peak in late August and September. Sockeye are present in smaller numbers and may be observed from July through September depending on the river system. Summer months from July onward provide the best viewing conditions and water levels tend to allow easier access to spawning grounds. Winter months offer fewer opportunities as rain raises river levels and visibility decreases. Timing varies by river system, so check local conditions before a trip.

The Washington Department of Fish and Wildlife provides illustrated identification guides for all Pacific salmon species on their website, with photos showing both ocean and spawning phase coloration. The linked wildlife guide for salmon in Washington includes habitat information, seasonal timing, and references for species-specific identification. University of Washington's fish identification resources contain detailed descriptions and photographs. iNaturalist observations of Washington salmon documented by naturalists and scientists provide real photos from the state with species confirmation. Local park and refuge visitor centers in areas like the Hoh River, Skagit Valley, and Puget Sound shorelines often stock printed guides and can provide live identification help. These resources are especially useful if you want to distinguish between closely similar species like Coho and Chum in early spawning phase.