The coho salmon, also known as silver salmon, is an anadromous Salmonid native to the coastal waters of the northern Pacific Ocean. Coho salmon are highly valued both commercially and recreationally for their flesh, making them an important species in the fishing industry although they are less popular commercially than other species of salmon. For example, coho salmon account for only 2% of wild salmon harvested in Alaska from 2006 to 2015, whereas pink salmon (Oncorhynchus gorbuscha) accounts for 65%. In addition to their commercial and recreational value, coho salmon are also sacred to many Native American cultures.
In the United States, coho salmon are a species of conservation concern. As a result, their populations are protected, and the harvest of this species is highly regulated. Anglers should understand and observe the regulations of the state they are fishing in to prevent overfishing and protect the coho salmon for future generations. In most states, there are dedicated fishing seasons for coho salmon and limits on the number of individuals and the size of those individuals that may be taken from the wild. In the supermarket, coho salmon fillets are harvested sustainably from managed populations. Federal, state, and tribal agencies take part in collectively and responsibly managing this resource.
Where Do Coho Salmon Live & What Do They Eat?
The range of the coho salmon extends from the Gulf of California, northward along the Pacific Coast, across the bearing sea, and then as far south as Japan in the Asian extent of the coho salmon’s range. This species is anadromous and is therefore born in freshwater, migrates to the ocean to mature, and then migrates back to freshwater to spawn. They spend 18 to 24 months (about 2 years) in the ocean and migrate to spawning grounds in September to December and sometimes as early as July.
Due to their migratory nature, the specific habitats occupied by coho salmon change throughout their lives. After the eggs hatch, the young fry remain in their nests until the egg yolk is completely absorbed. They then become free-swimming larvae that will hunt small invertebrates and zooplankton until they are large enough to establish territories in the shallow edges of streams where there is plenty of submerged debris to hide in and food to eat. The young salmon will live and hunt for aquatic insects and crustaceans in these territories. They will defend their territory from other fish for up to a year before making their way to the sea.
At sea, invertebrates like shrimp, insects, and plankton as well as small fish like herring make up the bulk of the coho salmon’s diet. Here, salmon abandon their defensive tendencies and instead swim in large schools to protect themselves from predators. These schools can be located at depths between 50 and 300 feet (15 to 91 meters).
The Importance of Coho Salmon in Local Ecosystems
Coho salmon are semelparous, meaning that they spawn once in their lifetimes and then die. Migratory populations will travel from the ocean to freshwater streams during spawning migrations. After spawning, they die and therefore the maximum age for a coho salmon is between 3 and 4 years. These great migrations from the oceans to natal streams cycle nutrients from the oceans to inland regions, using the salmon as vessels. While at sea, coho salmon consume prey and accumulate energy to use during their spawning migrations. During and after the migration, the salmon will become food for other animals.
Salmon migrations, or runs, come at exactly the right time for many animals that hibernate through cold winters. In Alaska, annual salmon runs occur before winter and provide Alaska’s brown bears (Ursus arctos) with nutrients that will help them make it through the winter. Other animals like river otters (Lontra canadensis), raccoons (Procyon lotor), and piscivorous birds also benefit from salmon migrations.
How Do I Identify Coho Salmon From Other Salmon?
Sometimes salmon species can be identified exclusively by locality but unfortunately, the coho salmon’s range overlaps with many other salmon species, making range-based identification difficult. The ocean-faring form of the coho salmon is silver in color with a light belly, hence the name “silver salmon,” and a darker dorsal surface.
They have fewer spots on their dorsal surface and fins than other species of salmon, a trait that can help distinguish them from other species. Additionally, the ocean form has a white gum line, a characteristic that can help differentiate them from Chinook salmon (O. tshawytscha), which has a black gum line.
Coho salmon in the breeding phase are dark colored with a red hue along their bodies. This hue is not as dramatic as the red color of sockeye salmon (O. nerka) but is still noticeable and vibrant. Additionally, breeding cohos lack any striping found in chum salmon (O. keta). Other traits to look for are enlarged, hooked teeth and red blushing on the operculum.
Are Coho Salmon Important Commercial or Recreational Fish?
Coho salmon make up a very small portion of commercial salmon fishery harvests in North America. Some populations of coho salmon are endangered and therefore taking salmon from the wild may impact the survival of these breeding groups. As a result, a coho salmon breeding program is in development in Chile to provide farm-raised coho salmon to North American supermarkets.
Salmon are popular sportfish and, when filleted, produce large, nutritious fillets that taste delicious. As a result, humans benefit greatly from salmon through recreational fishing. The inclusion of salmon in the human diet is not just for recreational purposes either. For many, salmon is an essential source of protein, vitamins, and essential fats. For some Native American cultures, salmon provides extremely important energy for the winter and is considered sacred in some cultures.
How Do I Fish for Coho Salmon?
Coho can reach an average length of 28 inches (71 cm) and weigh between 8 and 12 pounds (3.6 to 5.4 kg), making them a stunning catch. Some individuals can grow even larger, with exceptional specimens weighing over 35 pounds (15.9 kg)! As a result, it is no surprise that coho salmon are highly sought after by anglers along the West Coast of North America.
Fishing for coho salmon varies based on your location and the time of year. Coho salmon begin their spawning runs in September and into the winter. These salmon can be caught in rivers and tributaries with access to the ocean. Areas with gravel bottoms are the best to target during this life stage as adult coho salmon use this substrate to spawn. During the winter, juvenile fish can be found in the warmer waters of large rivers and in particularly deep water if you are fishing in the Great Lakes. During the summer, surface water temperatures are too warm for coho salmon, so they are more readily found in cooler, deeper waters. Spring is by far the best time to fish for coho as young, hungry fish migrate from spawning grounds to the ocean. They will be in search of food and will eagerly target an angler’s bait.
Landlocked lakes are sometimes stocked with coho salmon and the previously described fishing season may not apply because landlocked coho salmon cannot migrate to the ocean. Instead, deep lakes such as the Great Lakes become freshwater substitutes for the ocean. Juvenile coho salmon will migrate to the deeper lakes to hunt and grow. These salmon are usually hatchery-raised and will return to the streams in which they were stocked from September to October.
