Coho Salmon (Oncorhynchus kisutch)
Did You Know?
- Another common name for coho salmon is silver salmon.
- Coho salmon spawn only once.
- California is the southern end of coho salmon range in North America.
Podcast: A pit tag is injected into a coho salmon smolt. The tag will allow scientists to monitor the fish's progress as it moves downstream toward the ocean.
Credit: Brian Spence, NOAA
ESA Threatened - 3 ESUs
ESA Species of Concern - 1 ESU
California Central Coast coho salmon are one of NOAA Fisheries' Species in the Spotlight
|average 8 pounds (3.6 kg), but can weigh as much as 35 pounds (16 kg)|
|2 feet (61 cm)|
|dark metallic blue or greenish backs with silver sides and a light belly; spawning fish in rivers are dark with reddish sides|
|coho feed on plankton and insects in freshwater and switch to a diet of small fishes while in the ocean|
|migrate from a marine environment into freshwater streams and rivers of their birth; they spawn only once and then die|
The size of an adult coho may measure more than 2 feet (60 cm) in length and can weigh up to 35 pounds (16 kg). However, the average weight of adult coho is 8 pounds (3.6 kg).
Coho salmon have dark metallic blue or greenish backs with silver sides and a light belly and there are small black spots on the back and upper lobe of the tail while in the ocean. The gumline in the lower jaw has lighter pigment than does the Chinook salmon. Spawning fish in inland rivers are dark with reddish-maroon coloration on the sides.
Coho salmon adults migrate from a marine environment into freshwater streams and rivers of their birth in order to mate (called anadromy). They spawn only once and then die (called semelparity).
Adults return to their stream of origin to spawn and die, usually at around three years old. Some precocious males known as "jacks" return as two-year-old spawners. Spawning males develop a strongly hooked snout and large teeth. Females prepare several redds (nests) where the eggs will remain for 6-7 weeks until they hatch.
As the time for migration to the sea approaches, juvenile coho salmon lose their parr marks, a pattern of vertical bars and spots useful for camouflage, and gain the dark back and light belly coloration used by fish living in open water. Their gills and kidneys also begin to change at this time so that they can process salt water.
In their freshwater stages, coho feed on plankton and insects, and switch to a diet of small fishes as adults in the ocean.
Coho spend approximately the first half of their life cycle rearing and feeding in streams and small freshwater tributaries. Spawning habitat is small streams with stable gravel substrates. The remainder of the life cycle is spent foraging in estuarine and marine waters of the Pacific Ocean.
Critical habitat was designated on May 5, 1999 for the Central California Coast and Southern Oregon/ Northern California Coast coho salmon, and on February 24, 2016 for the Lower Columbia River coho salmon.status review report [pdf] (2005).
- various human-induced and natural factors, however, there is no single factor solely responsible for this decline, given the complexity of the salmon species life history and the ecosystem
A variety of conservation efforts have been undertaken with some of the most common initiatives including:
- captive-rearing in hatcheries
- removal and modification of dams that obstruct salmon migration
- restoration of degraded habitat
- acquisition of key habitat
- improved water quality and instream flow
The Pacific Coast Salmon Recovery Fund (PCSRF) was established by Congress in 2000 to support the restoration of salmon species. We oversee the Fund, and it is carried out by state and tribal governments.
The threatened and endangered ESUs of coho salmon were listed on June 28, 2005. Some of them had been previously listed in 1996 or 1997, but, because of legal and other issues, all listings were reaffirmed in 2005. The Central California Coastal ESU was uplisted from threatened to endangered in the 2005 listing.
The Puget Sound/Strait of Georgia ESU was listed as a Species of Concern on April 15, 2004.
A final critical habitat designation was published on May 5, 1999 for Central California Coast and Southern Oregon/Northern California Coasts coho salmon, and on February 24, 2016 for the Lower Columbia River coho salmon.Kingdom: Animalia
|Final Recovery Plan for Oregon Coast Coho Salmon||81 FR 90780||12/15/2016|
|Spotlight Species 5-Year Action Plan||n/a||02/10/2016|
|Proposed ESA Recovery Plan for Oregon Coast Coho Salmon||80 FR 61379||10/13/2015|
|Klamath River Basin 2012 Report to Congress||n/a||2014|
|Notice of intent to prepare a recovery plan for the Oregon Coast ESU||78 FR 38011||06/25/2013|
|Negative 90-day finding on an updated petition to delist Southern Oregon and Northern California Coast (SONCC) coho salmon ESU from the ESA||77 FR 55458||09/10/2012|
|Endangered Central California Coast ESU now includes all naturally spawned populations that occur in Soquel and Aptos creeks||77 FR 19552||04/02/2012|
|Negative 90-day finding on a petition to delist Southern Oregon and Northern California Coast (SONCC) coho salmon ESU from the ESA||77 FR 1668||01/11/2012|
|Negative 90-day finding on a petition to delist coho salmon under the ESA||76 FR 62375||10/07/2011|
|Species of Concern Fact Sheet: Detailed||n/a||06/10/2009|
|Federal Register Notices for Coho Salmon||various||various|
|Recovery Plans and Related Documents||n/a||n/a|
- NOAA West Coast Regional Office Coho Salmon Species Information
- NOAA's National Marine Sanctuaries Encyclopedia
- NOAA Critical Habitat Information
Updated: January 5, 2017