Coho Salmon

Identifying features  One easy identifier from other pacific salmon is their black gum-line or “lips” with white main gums and mouth. The body of Coho salmon has scattered spots mainly on the upper-tail fin and a dark metallic green/blue back with bright silver sides while in the ocean. While spawning Coho salmon undergo severe morphological changes; their back remains deep blue/green with their spots remaining distinct, however their sides become a deep red or maroon and males develop a prominent hooked upper jaw. Late into spawning many fish also develop white fins.

Habitat  Coho Salmon hatch in freshwater rivers where they live for one winter before swimming downstream into the ocean and spend 2 summers in large schools around the continental shelf before swimming back upstream to the same location on the river they hatched to lay eggs and spawn. 

Prey  Before they journey to saltwater, coho fry feed primarily on crustaceans, zooplankton and small invertebrates in rivers. Once they migrate to the ocean their diet shifts, acting as opportunistic feeders preying on small fish like herring and juvenile fishes mainly Chum and Pink salmon as well as squid and crustaceans, gaining as much fat and muscle as possible before returning to their spawning grounds. Once they re-enter freshwater they stop eating and their stomachs shrink to make room for sperm and eggs. Because they stop eating their bodies rely on their stored fat to sustain them through their journey constantly swimming upstream for miles at a time. Pigments from their flesh extremities are moved towards their eggs and spawning colors as well as being digested once they begin to run out of fat leading to white fins in fish later in the spawning season.

Predators  Predators of Coho vary throughout their changing habitat. During the beginning of their life they are preyed on by larger river fish like trout, sculpins, and even pike-minnows. Once they enter saltwater they are targeted by marine mammals like sea lions, seals, and even orca as well as cormorants, eagles, kingfishers and larger fish like sharks. When they return to freshwater they are an important food source for otters, bears, as well as scavengers that prey on salmon that die on their journey to spawn. Dead salmon in rivers bring an immense amount of nutrients inland from the ocean that benefits the whole ecosystem surrounding rivers. They are also fished in both fresh and salt water for their meat as well as sport fishing with Coho being known for their acrobatics, often jumping out of the water while hooked.

Life Cycle  Coho are anadromous meaning they spend parts of their life in both freshwater rivers as well as the ocean. They hatch in rivers and small streams where they spend at least one winter and sometimes over a year feeding and growing before migrating to the ocean. Once in the ocean they continue to feed and mature in large schools for up to 18 months before they swim back up the river they first migrated out , where they swim upstream against the current sometimes for hundreds of miles, returning to the exact grounds they were hatched to spawn and lay eggs.

Fun Facts: 

Their scientific name Oncorynchus kisutch comes from Russian кижуч (Kizhutch) , a common name for them in Russia.

Like almost every other Pacific salmon their english name Coho originates from a language in the coast salish family for Coho it’s the upriver dialect of Halkomelem’s word for them: kʷə́xwəθ (Kwōxweth)

References:

Fisheries, N. (2025, April 1). Coho Salmon. https://www.fisheries.noaa.gov/species/coho-salmon#:~:text=While%20in%20fresh%20water%2C%20young,orcas%20feed%20on%20adult%20coho 

Coho. Pacific Salmon Foundation. (2022, April 29). https://psf.ca/info/coho/#:~:text=Coho%20spend%20at%20least%20one,very%20quickly%20as%20a%20result. 

FirstVoices.com. FirstVoices. (n.d.). https://www.firstvoices.com/halqemeylem/words/05d2732b-822a-4b83-9cbb-81f40a734faa