This species is listed as Least Concern in view of the large extent of occurrence (EOO), large number of subpopulations, large population size, and lack of major threats. The population trend over the past 10 years or three generations is uncertain but likely relatively stable, or the species may be declining but not fast enough to qualify for any of the threatened categories under Criterion A (reduction in population size). However, it should be noted that treatment at species-level masks many significant declines that are in progress and well documented.

The native range of this species includes the Pacific Ocean and tributary drainages; in North America presently from the Sacramento-San Joaquin system (sometimes farther south) north to Point Hope, Alaska, and in north-eastern Asia, from northern Japan to the Anadyr River. This species has been widely stocked elsewhere.

In the Columbia River basin, the Hanford Reach supports the largest population of fall Chinook Salmon; annual production is an estimated 20-25 million subyearling salmon (P. Hoffarth unpublished data).

It is found in Arctic waters from the Chaun Bay (East Siberian Sea) and Arctic Canada (Mackenzie River) to the south through the Bering Strait up to Hokkaido Island and the Pacific side of northern Honshu (Japan); as well as the Amur Liman and rivers of Primorsky Krai, including Kamchatka, the Konandorskiye, and the Aleutian Islands, with the north-western border as the rivers of the Chaunskaya Guba bay; and along the North American coast up to the central part of Baja California (Mexico) where it is considered a vagrant.

There is no information on the overall population size and trend, but this is one of the least abundant of the Pacific Salmon (Lee et al. 1980).

In a survey of populations in the contiguous U.S., Huntington et al. (1996) identified 32 healthy native stocks of fall Chinook Salmon, all in Washington and Oregon, and three healthy native stocks of spring or summer Chinook Salmon, all in Washington. At least 50 stocks have been extirpated; see Nehlsen et al. (1991) for a review of the status of various at-risk/special concern populations from California, the Oregon coast, the Columbia River basin, and Puget Sound. Of 866 stocks in British Columbia and Yukon, Slaney et al. (1996) categorized 17 as extirpated, 47 as high risk, six as moderate risk, seven as special concern, 330 as unthreatened, and 459 as unknown status. Regarding spring runs outside the Sacramento-San Joaquin population: the run in Salmon River drainage (North and South forks, and Wooley Creek, California) apparently was stable at 1,000-1,500 adults in the 1980s; the flood of 1964 reduced available habitat for population in the South Fork of the Trinity River, and the population there now is much smaller than previously; most individuals in the Klamath-Trinity drainage are derived from hatchery stock. Ratner et al. (1997) conducted a population viability analysis of spring Chinook Salmon in the South Umpqua River, Oregon (this is part of the Oregon Coast ESU) and found a 95% probability of persistence of 200 years with no further habitat destruction; with continued habitat destruction, the population was projected to be almost certainly extirpated within 100 years.

In Asian waters, it is most often found in the rivers of Kamchatka, and is found in much lower abundance in the rest of the range (Tokranov and Sheiko 2006).

Chinook Salmon generally spend most (often two to four years, but up to six years) of their lives in the ocean. For spawning, this species migrates up to several hundred kilometres upstream to their natal stream, where eggs are deposited in gravel bottoms of large streams and rivers. Populations may differ dramatically in the timing of adult migration and, to a lesser extent, timing of spawning. There are two basic behavioural forms: stream-type and ocean-type. Stream-type are typical of northern populations (i.e., Alaska and northern B.C.) and headwater (high elevation) tributaries of southern populations. These spend one full year as juveniles rearing in fresh water before migrating to sea, perform extensive offshore oceanic migrations, and typically return to their natal river in spring or summer, several months prior to spawning; occasionally males mature without ever going to sea. The ocean-type is typical of populations on the North American coast south of 56 degrees north latitude; these migrate to sea during their first year of life (normally within three months of emerging from spawning gravel), spend most of their ocean life in coastal waters, then return to their natal river in fall, a few weeks before spawning.

In Asian waters, it is an anadromous fish with long freshwater and marine periods, and can form resident forms in some rivers (although not Kamchatka). It matures in the fourth to seventh years of its life. Spawning migration to the rivers of the peninsula Kamchatka occur in May to July, and spawning lasts from June to July until the end of August. Spawning grounds are located in the upper reaches of large rivers, mainly in the main channel. Fecundity in the Kamchatka River is 4,200-20,000 eggs. After spawning, mature individuals die, as for all Pacific Salmon species. Embryos stay in the ground for six or seven months, then hatching from eggs takes place in autumn and coming out of spawning hillocks in spring (early March). Juveniles coming out of redds and spend one to two years in fresh water. At this time, the juveniles eat air insects, their larvae, crustaceans and young fish. In the sea, the main diet is plankton crustaceans (primarily euphausids), fish and squid. It winters in the waters near the Aleutian Islands of the Pacific Ocean and the Bering Sea. It is the largest representative of Pacific Salmon, with a maximum length of 149 cm and a body weight of 61.4 kg. In the rivers of Kamchatka, individuals with lengths of 78-103 cm and body weight of 5.5-17.0 kg are usually caught (Tokranov and Sheiko 2006).

Declines in this species have been attributed to the adverse effects of logging, mining, irrigation withdrawals, and overfishing, then construction of hydroelectric dams blocked migrations and resulted in high mortality of smolts in turbines (Nehlsen et al. 1991, Williams et al. 1992). Spawning runs continue to be threatened by construction of dams and degradation of natural environment. Extinctions or large declines of some local native populations in recent decades may have been masked by releases of non-native hatchery stock (Williams et al. 1992).

Juveniles incur high mortality as they migrate through river systems and out to sea. Sources of mortality include hydroelectric turbines, mechanical bypass facilities (including transportation by barge or truck), and predation by non-native fishes. Gas bubble trauma (GBT) associated with total dissolved gas supersaturation (TDGS) at spillways also causes mortality and detrimental sublethal effects, but passage of juveniles through spillways may be the least damaging of the routes for juvenile passage at dams (Backman et al. 2002). In the Columbia River basin, adults were rarely observed with GBT, despite high TDGS levels (Backman and Evans 2002).

Concurrent with the construction of fish hatcheries, bacterial kidney disease became prevalent and may now play a significant role in mortality.

A change in climate, beginning around 1977, led to poor ocean survival.

The populations of the basins of the rivers Penzhin, Talovka, Bolshaya, Avacha, Paratunka and Lisinskaya (Bering Island) are low and are mainly limited by the area of suitable spawning grounds. In the basin of Avachinskaya Bay and Bolshaya River, intensive poaching is also a threat (Tokranov and Sheiko 2006).

This is a very valuable commercial fish species.

Currently, on a range-wide basis, this species is of relatively low conservation concern. However, it is of high conservation concern in certain regions, particularly in the southern part of the range. A recent analysis indicated a marked reduction in survival across the Pacific Coast of North America (southern region), and patterns suggest broad scale oceanic factors are leading to observed reductions in smolt to adult survival rates (Welch et al. 2021). In the northern part of the North American range, the species is still abundant but productivity has recently declined raising local conservation concerns (Jones et al. 2020)

At present, Chinook Salmon catches in all waters of the Kamchatka region and Koryak Autonomous District are regulated by the existing Fisheries Regulations. Due to a sharp decrease in the numbers of this species in the Bolshaya River basin, a ban on its specialized fishing was introduced in 2000. Taking into account the increased poaching catch in recent years, it is necessary to strictly control the recommended catch of Chinook Salmon (if necessary - to introduce a complete ban) and organize special studies to study the current state of the populations in the basin. It is highly desirable to cryopreserve all small populations of Chinook Salmon. In the Bolshaya River basin, where there is intensive harvesting of other salmon species, artificial breeding of Chinook Salmon is necessary (Tokranov and Sheiko 2006).

While focus on species-level status assessments are an important first step, the IUCN Species Survival Commission (SSC) Salmon Specialist Group (SSG) emphasizes the need to characterize status of Pacific Salmon at a more granular, population-level scale (identified as “subpopulations” in the IUCN Red List Guidelines) to provide meaningful guidance to stem the loss of biodiversity across the natural range of the species. There are many examples of declines in wild Pacific Salmon in both North America and Asia, particularly in the southern portion of their range given the degree of degradation and fragmentation of habitat there and the more immediate risk of climate change impacts. At the same time, there are large-scale ocean drivers that appear to be affecting species broadly across the North Pacific, regardless of their freshwater origin. Two excellent examples exist of assessment approaches and policies in the US (Waples 1991) and Canada (DFO 2005, COSEWIC 2018) that establish an effective framework for Pacific Salmon conservation. These efforts involve identifying population units based on a variety of criteria including examination of traits that are important in the evolutionary process and future adaptation. In these examples, assessments are conducted at a more granular, population-level, resulting in listings for individual population units, with identification of needed conservation actions specific to each unit. An example of assessing range-wide status of the species and at the individual subpopulation level in the IUCN Red List now exists for Oncorhynchus nerka (Rand 2011). While the amount of effort required to rigorously assess the species is substantial, we encourage efforts like this applied to the other species in the genus.