# Coho Salmon (Oncorhynchus kisutch) - Web page: https://www.funwildfacts.com/asien/fish/coho-salmon - Published: 2026-05-30 - Last updated: 2026-05-30 ## Overview The Coho salmon (Oncorhynchus kisutch) is a medium-sized Pacific salmon species native to the coastal waters of North America and eastern Asia. This impressive anadromous fish spends most of its life in the ocean but returns to freshwater rivers to reproduce. The Coho salmon is characterized by its streamlined body and silvery appearance during its ocean phase, while undergoing dramatic color changes when it migrates upstream to spawn. The species gets its common name from its silver-bright appearance in the ocean, though it's also called 'silver salmon' in many regions. During its time in the Pacific Ocean, the Coho salmon leads a pelagic lifestyle, actively hunting small fish, crustaceans, and squid. When the fish approaches sexual maturity, typically after 18 months at sea, it begins its spectacular migration back to the same freshwater stream where it hatched. This extraordinary navigational ability is guided by the fish's sense of smell, enabling it to recognize the chemical composition of its natal waters. During the upstream journey, the Coho stops eating entirely and lives solely on the energy reserves accumulated during its ocean life. When Coho salmon reach their spawning grounds, they undergo a dramatic transformation. Females develop darker coloration with reddish-brown tones on their sides, while males develop a hooked jaw (kype) and intensely red sides with dark green heads. After the female digs a depression in the gravel bed and deposits her eggs, the male fertilizes them. Both sexes typically die shortly after spawning, making the Coho salmon a semelparous organism—a species that reproduces only once during its lifetime. The Coho salmon is both ecologically and economically significant. As a keystone species, it transports nutrients from the ocean to freshwater ecosystems and forests when it dies after spawning, benefiting everything from insects to bears and trees. Commercial and recreational fishing for Coho is important in North America, and the species has been introduced to the Great Lakes and certain other areas. However, some wild populations are threatened due to habitat loss, dam construction, and overfishing, leading to extensive conservation efforts and hatchery programs. ## Quick facts - Weight: 2.5–16 kg - Length: 0.45–1.08 m - Top Speed: 35 km/h - Lifespan: 3–5 yrs - Diet: Omnivore - Conservation Status: Least Concern ## Habitat The Coho salmon has a complex life cycle requiring both freshwater and marine habitats. The early life stages are spent in streams and rivers with cold, oxygen-rich water and gravel bottoms where eggs can develop. Juvenile fish remain in freshwater for up to two years, often in smaller tributaries and creeks with good shading from vegetation and abundant insect prey. During this period, they need protection from predators in the form of underwater vegetation, rocks, and overhanging trees. When the Coho salmon migrates to the ocean, it spends 18 months in coastal and open ocean areas of the Pacific. Here it lives a pelagic life in the upper water layers where it actively hunts. Coho salmon prefer colder waters and often follow currents and temperature gradients where food is plentiful. When it's time to spawn, they navigate back through estuaries and upstream in rivers, preferring shallow areas with gravelly bottoms and good water flow for depositing their eggs. Most populations require free-flowing rivers without physical barriers like dams to complete their life cycle. - Ocean - River - Lake - Coast ## Seasonal Behavior The Coho salmon's seasonal patterns vary depending on geographic population, but most follow a clear annual cycle. Spawning runs typically occur from autumn to winter, with peaks between September and December along the North American Pacific coast. Eggs are laid in late autumn and winter, and after an incubation period of approximately 90-120 days, fry hatch in spring when water temperatures rise. Juveniles spend spring and summer in freshwater where they rapidly grow on insects and small crustaceans. Migration to the ocean occurs mainly during spring when the fish are 1-2 years old and have developed their silvery smolt coloration. At sea, Coho salmon follow seasonal movements in relation to water temperature and food availability, often with northerly migrations in summer and more southerly or deeper zones in winter. ## Breeding - Incubation: 90 days - Offspring: 2400–4500 ## Behavior & Ecology - Activity Pattern: Diurnal - Social Behavior: Coho salmon live mostly solitary lives in the ocean, although individuals may gather in areas with abundant food. During spawning migrations they form larger aggregations in rivers and display territorial behavior at spawning sites. - Migration: Migratory - Population: Population varies greatly between different rivers and regions; some runs are stable while others are threatened or recovering thanks to conservation efforts. ## Did you know? - Coho salmon can jump up to three meters high to navigate waterfalls and other obstacles during their upstream migration! - A female Coho salmon can lay between 2,400 and 4,500 eggs, which she carefully covers with gravel to protect them. - During their ocean phase, a Coho salmon can grow from just a few grams to over 15 kilograms in only 18 months—a growth rate that surpasses most other fish! - Coho salmon flesh is deep red or orange due to carotenoids obtained from eating crustaceans and small fish. - When Coho salmon return to freshwater, they stop eating entirely and live off their fat reserves until they spawn and die—a journey that can span hundreds of kilometers! - Coho salmon can recognize their birth river by remembering the smell of the water from when they were fry—an incredible feat of olfactory memory! - Bears, eagles, and other predators depend on the annual salmon run, and it's estimated that bears can spread nutrients from salmon hundreds of meters into the forest. - Young Coho salmon are highly territorial in freshwater, with dominant individuals defending the best feeding spots from their siblings! ## Taxonomy - Kingdom: Animalia - Class: Actinopterygii - Order: Salmoniformes - Family: Salmonidae - Species: Oncorhynchus kisutch ## Image - URL: https://images.djurfakta.com/animals/silversax/1777580165734-1.jpg - Photo: NOAA - License: Public domain ## Other languages - sv: https://www.djurfakta.com/asien/fish/silversax - da: https://www.dyrefakta.com/da/asien/fish/solvlaks - no: https://www.dyrefakta.com/asien/fish/solvlaks