Coho Salmon

Coho Salmon, commonly known as silver salmon, is a mid-sized Pacific salmon prized by anglers for its aggressive, acrobatic fights and by fisheries for its firm, flavorful flesh. Native to coastal rivers and streams from California north through Alaska and across to the Russian Far East, Coho typically spend one year rearing in freshwater streams before migrating to the ocean, where they grow rapidly for roughly a year and a half before returning to spawn. Unlike Chinook, which favor large rivers, Coho often use smaller coastal streams and tributaries for spawning, making them an important indicator species for the health of coastal watershed ecosystems.

Key field marks:

• Small black spots limited to the back and only the upper lobe of the tail fin (unlike Chinook, which has spots on both lobes)
• White gums at the base of the teeth, unlike Chinook's black gums
• Bright metallic silver sides with a bluish-green back in ocean phase
• Spawning males and females develop bright red to maroon sides with a greenish head
• Slightly smaller and slimmer than Chinook Salmon

Look-alikes: Most often confused with Chinook Salmon; the tail spotting pattern and gum color are the most reliable distinguishing features between the two species.

Coho Salmon range along the Pacific Rim from central California north through British Columbia and Alaska, and across to the Russian Far East and northern Japan. They favor smaller coastal rivers, tributaries, and streams with abundant cover such as pools, undercut banks, and woody debris, where juveniles typically rear in freshwater for about a year before migrating to sea. After roughly 18 months feeding in nearshore and open Pacific waters, adults return to their natal streams to spawn, usually in fall. The species depends heavily on healthy, well-vegetated stream habitat and is particularly sensitive to loss of small stream and wetland habitat used for juvenile rearing.

Coho Salmon juveniles are notably territorial in freshwater, establishing and defending feeding stations in streams where they prey on aquatic and terrestrial insects for up to a year before migrating to the ocean as smolts. At sea, Coho feed opportunistically on small fish, squid, and crustaceans, growing quickly during their relatively short ocean residency compared to other Pacific salmon. Returning adults are known for their strong, energetic upstream migrations and aggressive spawning behavior, with males competing for access to females on the spawning grounds. Like all Pacific salmon, Coho are semelparous, dying within days to weeks after spawning in gravel redds during the fall.