Chinook Salmon (Okanagan population)
- No Status NS
- Special Concern SC
- Threatened TH
- Endangered EN
- Extirpated EX
|Not at Risk
- Not at Risk NR
- Special Concern SC
- Threatened TH
- Endangered EN
- Extirpated EX
At a glance
The largest of Pacific salmon species, an adult Chinook salmon is capable of growing to five feet long and weighing 45 kilograms or more. Once abundant from Alaska all the way down to Southern California, Chinook salmon numbers have been declining steadily, largely due to human factors. In Canadian waters, the Okanagan population of Chinook salmon has been affected by dams along its spawning route, historic overfishing, new predators and other non-native fish becoming competitors. Spawning numbers are now as low as 50 adults per year, making this small population extremely vulnerable.
About the Chinook salmon
Chinook salmon are born in freshwater and remain there for about a year before moving out to the Pacific ocean, where they remain until reaching sexual maturity. This can occur between ages one and seven, and typically around age four. At that time the Chinook salmon begin the long journey home to spawn, and shortly thereafter, to die. Chinook will not feed during their migration home, so they slowly deplete their energy reserves. Their final triumph is to spawn. All Chinooks die shortly after spawning.
Because of the varying years required for Chinook salmon to become sexually mature, the fish in any spawning run vary greatly in size. While a mature 3-year-old might weigh less than 2 kilograms, a mature 7-year-old could be over 20 kilograms. Females tend to sexually mature later than males, making them the larger fish in the spawning runs.
During spawning, each female deposits from 3,000 to 14,000 eggs in several gravel nests, or redds, which she excavates in relatively deep, moving water. The newly hatched babies, called alevins, live in the gravel for several weeks as they slowly absorb the food in their attached yolk sac. Eventually the juveniles, now called fry, wiggle up through their gravel underwater nests and remain in fresh water for a year before migrating to the ocean in their second year of life.
Juvenile Chinooks feed on plankton and insects. Once in the ocean, they can double their weight each year on a diet of other fish, squid, and crustaceans. A 126-pound Chinook salmon taken in a fish trap near Petersburg, Alaska in 1949 is the largest on record. The largest sport-caught Chinook salmon was a 97-pound fish taken in Alaska’s Kenai River in 1986.
How to recognize a Chinook salmon
The Chinook is easily distinguished from other salmon, by factors other than its larger size. Anglers often refer to it as the handsomest of the salmon. The Chinook has black gums, giving it the name “blackmouth” in some areas. Black dots extend from its gill plates across its back and tail. Ocean dwelling Chinook have blue-green sides which blacken in summer, and silver undersides. Also, unique in scent, those familiar with salmon can identify the Chinook by smell alone.
Chinook are also the only salmon to have two different genetic strains, giving it either white or pink meat.
When Chinook are on their spawning run, their colour is red to copper to almost black, depending on locations and maturity. Males have deeper colours than the females.
Where Chinook salmon live
The Chinook salmon (Okanagan population) are anadromous salmon migrating to and from the Pacific Ocean through the Columbia River and Okanagan Lake. Independent yet “loosely schooling,” the Chinook tend to congregate together in areas with underwater structures, such as reefs, rocks, banks, and depressions. While spawning in summer and early fall, they take routes close to land and generally hole-up overnight in the calm waters close to shore.
The Chinook salmon (Okanagan population) once occupied the area from Osoyoos Lake to Okanagan Lake, but McIntryre Dam near Oliver, BC, an irrigation diversion project completed in 1954, now blocks fish from continuing upriver. Currently, the population’s northern freshwater limit is the McIntyre Dam and its southern freshwater limit may be the north basin of Osoyoos Lake, immediately north of the BC border with Washington State.
Some of the Chinook salmon appear to be non-anadromous, spending their entire lives in Osoyoos Lake. The spawning success of this group is unknown.
Why it’s at risk
North Pacific Chinook salmon catches during the late 1970s and early 1980s averaged more than 4 million fish per year. The United States harvested the majority of the catch followed by Canada, Japan, and the USSR. Today, this Okanagan population is the only remaining Columbia Basin population of Chinook salmon in Canada.
The Okanagan population was once large enough to support the regional food and First Nations trade fishery, prior to the settlement of non-native people. Now, spawning numbers are now as low as 50 adults per year, making them extremely vulnerable. In addition to the habitat loss the Chinook salmon experienced after the erection of McIntyre Dam, historic overfishing in the Columbia River, high salmon mortality rates caused by other dams downstream, heavy fishing in the ocean, new predators and other non-native fish becoming competitors all further depleted this Okanagan population.
It is also believed that hatchery projects in the Columbia River may be negatively affecting the genetic strength of the Chinook salmon of the Okanagan. In 2005 the species was classified as Endangered by COSEWIC and considered at imminent risk of extinction. However, recent rescue efforts, and evidence that the population may be reproducing with populations in adjacent areas of the Columbia River basin, resulted in COSEWIC downgrading the status to Threatened in November 2006.
What’s being done
In 2005, the Committee on the Status of Endangered Wildlife conducted an emergency assessment on the this population of Chinook salmon, and concluded that, “The Okanagan Chook salmon is facing an imminent threat to its survival, such that an Emergency Listing of the Species as Endangered is warranted,” although subsequently the designation was reduced in November 2006 to Threatened because of some encouraging rescue signs. This population is now under consideration for addition to SARA. If the Chinook salmon Okanagan population is added to SARA, it will benefit from the protections afforded by SARA. The species currently receives some protection under the Fisheries Act, which prohibits the destruction of critical habitat.
What can you do?
Chinook salmon will get the protection they need only if all Canadians work together to reduce threats. Each and every one of us has a responsibility to ensure that we do everything possible to protect and recover all species at risk. Find out more about Chinook salmon and get involved with the Habitat Stewardship Program for Species at Risk (HSP) or another conservation organization.
For more information, visit the Species at Risk Public Registry Profile
Scientific name: Oncorhynchus tshawytscha
Taxonomy: Fishes (marine)
SARA Status: No Status
Region: Pacific Ocean
Home is where the heart is
After years at sea, this powerful fish makes a marathon journey back to the stream where it was born—to spawn, and then, to die. Chinook salmon do not feed during the spawning run, so their condition deteriorates over the weeks it takes them to swim upriver, during which time they use stored body reserves for energy and the development of reproductive products. Their last hurrah is to spawn in the river where they were born. They then die, and float back down the river, where they rejoin the food chain by being eaten by other animals.
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