dog salmon, Keta salmon, O. canis (Suckley, 1859), O. consuetus (Richardson, 1854), O. dermatinus (Richardson, 1854), O. lagocephalus (Pallas, 1814), Salmo canis Suckley, 1859, S. consuetus Richardson, 1854, S. dermatinus Richardson, 1854, S. keta Walbaum, 1792, S. lagocephalus Pallas, 1814, Salmo keta (Walbaum 1792).

Nonindigenous Occurrences: Chum salmon have yet to be established beyond their native range (Behnke 2010). Oncorhynchus keta was introduced to Chile for ranching, but the attempt was unsuccessful. It was also introduced to the Gulf of Riga, in the bay of the Baltic Sea, but has only been found in small numbers (Ojaveer 1995).

Water temperature is a determinant of salmon distribution (Welch et al. 1995). In the Subarctic Region, Oncorhynchus keta occur in waters that have surface temperatures that are 3°C or greater, and its distribution shifts northwards during the summer (Bakkala 1970). Oncorhynchus keta makes diel vertical movements through the thermocline during the day to feed and remains near the surface waters during the night, so it experiences a broad range of temperatures (Azumaya and Yukimasa 2005). Sea surface temperature may limit the distribution of chum salmon during the night. In the Bering Sea, this species regularly moves vertically to waters that are under 5°C to feed, but these cooler temperatures may be sub-optimal. It has been suggested by Azumaya and Yukimasa (2005) that diving from warmer waters and making vertical movements allow chum salmon to feed in sub-optimal temperatures. Chum salmon exhibit homing migration from the Bering Sea to the warm waters on the coast of Hokkaido, Japan, and avoids warm temperatures above 15°C by making vertical movements to deeper waters.  Chum salmon are strong swimmers that have been documented migrating about 2820 km to its spawning ground in the Yukon River from sea (Behnke 2010). Oncorhynchus keta from Asia migrate towards the Bering Sea in the winter and spend their first winter in the North Pacific and the rest of their winters in the Gulf of Alaska (Urawa et al. 2004). They predominately overwinter in waters with temperatures of 4°-6°C. 

Oncorhynchus keta has short freshwater and extensive marine life stages (Salo 1991). Eggs are relatively large in size, and the alevins are large and mobile (Salo 1991). Chum salmon eggs and fry exhibit a greater salinity resistance than coho, chinook, and sockeye salmon (Clarke and Hirano 2010). The fry emerge in late winter to early spring (Behnke 2010). Soon after they emerge, the fry migrate to from the stream to sea (Salo 1991), and are about 30 mm in length (Behnke 2010). At sea, they reach maturity between 2-5 years and return to their home stream to spawn (Salo 1991). Oncorhynchus keta populations are distinguished as summer or fall races according to the time of year they return to spawning streams. Summer spawning occurs in June-July while fall spawning occurs from September through December.  Fecundity ranges from 900 to 8,000 eggs (Bakkala 1970), which incubate in gravel redds for 50-130 days (Hale et al. 1985). Chum salmon are semelparous and anadromous, and are able to spawn in streams of varying sizes (Salo 1991). All die after spawning. Chum and pink salmon are closely related and may spawn in the same streams but avoid hybridization by spawning at a different time or at a different spawning ground (Behnke 2010). These two species are able to produce fertile hybrids, but no self-sustaining hybrid populations are known.

Chum salmon fry feed on small invertebrates and crustaceans (Behnke 2010). Adult chum salmon exhibit opportunistic feeding on invertebrates and fishes. They preferentially feed on larger zooplankton over small zooplankton (Higgs et al. 2010). During the winter, this species’ diet is composed of fish, squid, or euphausiids. Bald eagles prey on chum salmon carcasses after they spawn (Harvey et al. 2012).

Wild populations of Oncorhynchus keta occurring in the Columbia River basin and Hood Canal, Puget Sound are protected under the Endangered Species Act.

Potential pathway(s) of introduction: Unauthorized release

Oncorhynchus keta was introduced to the Great Lakes region by American and Canadian agencies in order to develop a self-sustaining, wild population to contribute to food, commercial, and recreational fisheries (Crawford 2001). From 1908 to the 1940s, Oncorhynchus keta were raised in hatcheries in Michigan, Pennsylvania, and Wisconsin, for release into Lakes Superior and Lake Huron (MacCrimmon 1977). The chum salmon were unable to form a self-sustaining population, and stocking programs ended in 1945.

Oncorhynchus keta has a moderate probability of establishment if introduced to the Great Lakes (Confidence level: High).

The native ranges of Oncorhynchus keta have similar climatic conditions as the Great Lakes. Oncorhynchus keta can tolerate a broad range of salinity and survive abrupt changes in salinity (Clarke and Hirano 2010). Optimal water temperatures for Oncorhynchus keta are between 5-27°C (Hale et al. 1985). This species experiences high mortality when dissolved oxygen drops below 2 mg/L.

Oncorhynchus keta is capable of surviving winter temperature in the Great Lakes, but its ability to overwinter is limited by its oxygen requirements. There are populations of Oncorhynchus keta that overwinter in the North Pacific, the Gulf of Alaska, and the Bering Sea (Urawa et al. 2004), usually in waters that are 4-6°C. During homing migration, chum salmon make vertical diel movements to deeper waters to feed, experiencing temperatures under 5°C regularly (Azumaya et al. 2005). Although chum salmon can tolerate such low temperatures, it may not be able to for long periods of time, and behaviorally avoids them by moving to shallower waters periodically.  

Oncorhynchus keta opportunistically feeds on zooplankton, invertebrates, mollusks, and fishes, and has a relatively broad diet compared to other Oncorhynchus species (Behnke 2010, Kaeriyama et al. 2004). The chum salmon fry feed on small invertebrates as they migrate downstream and on crustaceans as they move into estuaries. Oncorhynchus keta will likely find an appropriate food source if introduced to the Great Lakes. Alewife, Alosa pseudoharengus, is an established nonindigenous species in the Great Lakes and may provide a food source for introduced salmon (Crawford 2001), such as Oncorhynchus keta.

For successful reproduction, chum salmon require loose streambed gravel to lay their eggs (Bakkala 1970). Chum salmon migrate upstream to rivers to spawn, can reproduce successfully in intertidal zones at the mouth of streams (Behnke 2010) and in lakes with upwelling groundwater (Wilson 2006). Chum salmon migrate upstream to spawn at temperatures under 15°C and dissolved oxygen levels greater than 6.3 mg/L (Hale et al. 1985). They have been observed migrating upstream in waters that are as low as 4.4°C, and temperatures above 25.5°C are lethal. The chum salmon fry prefer temperatures of 12-14°C, and have lethal water temperature limits above 23.8°C and below -0.1°C (Brett and Alderdice 1958). Chum fry undergoes developmental changes for life in sea water, and migration to sea water within the first summer is necessary for survival (Hale et al. 1985); however, chum salmon have been reared to maturity in freshwater in captivity (R.L. Burgner, Fisheries Research Institute, University of Washington, Seattle, Washington, pers. comm. In Salo 1991).

Previous introductions of Onchorhynchus keta to the Great Lakes did not result in the establishment of self-sustaining populations (Crawford 2001, MacCrimmon 1977). It was also introduced to the Gulf of Riga, in the bay of the Baltic Sea, but has only been found in small numbers (Ojaveer 1995). Oncorhynchus keta is predicted by Kolar and Lodge (2002) to be intentionally introduced to the Great Lakes for the purpose of aquaculture or sport, and to spread at a fast rate if introduced. Although Kolar and Lodge (2002) predict high probability of establishment and spread, the history of this species in the Great Lakes, which includes nearly 40 years of stocking, suggest that some unknown factors prevent its establishment in the Great Lakes region.  

There have been several studies conducted on how climate change affects chum salmon, but none have predicted how climate change in the Great Lakes may impact chum salmon establishment. In the subarctic North Pacific, increased chum fingerling growth rates correlated with increased zooplankton biomass as a result of climate change in the late 1980s (Seo et al. 2006). In the Gulf of Alaska, chum salmon diets switched from one dominated by gelatinous zooplankton to one with greater diversity of zooplankton species due to climate alterations caused by El Niño and La Niña events (Kaeriyama et al. 2004). Models developed by Harvey et al. (2012) predict that chum salmon post-spawning carcasses will decompose at a faster rate due to warming and climate change. Chum salmon are a major component of overwintering bald eagle diets in the Puget Sound, and faster carcass decomposition rate may decrease the biomass of carcasses available for the bald eagles. The effects of climate change such as warmer water temperatures and shorter duration of ice cover may aid the establishment of Oncorhynchus keta and enable it to overwinter in the Great Lakes. Chum salmon fry require migration to seawater (Hale et al. 1985), so increased salinization may increase their survival in the Great Lakes.

This species may be vulnerable to habitat degradation. Chum salmon populations that spawned in the Columbia River basin had declined by the 1950s (Behnke 2010). The spawning habitat quality was degraded by upstream logging, pollution and water diversions, resulting in spawns of 1,000 to 5,000 fish. By 2011, spawning runs had attained 10,000 fish for the first time in 46 years after the implementation of habitat protection and enhancement.

Summary of species impacts derived from literature review. Click on an icon to find out more...

Environmental	Socioeconomic	Beneficial

Chum salmon can hybridize with chinook and kokanee salmon (Sasaki et al. 1968, Seeb et al. 1993), popular sport fish in the Great Lakes, but there is no indication that it can hybridize with fish native to the Great Lakes. Introduced salmon, such as chum salmon, may compete with native species for food (Crawford 2001), but what species will be impacted by the introduction of chum salmon has not been investigated. Crawford (2001) suggested that, as vectors for parasites, hatchery-reared salmon may threaten native fish species. Sea lice (Lepeophtheirus salmonis) infection rates in wild juvenile chum salmon and pink salmon were higher for populations that occurred near salmon farms than those that were not located near salmon farms in British Columbia, Canada (Morton et al. 2004). Sea lice are ectooparasites that can infect other salmonoid species, but fall off the host when they migrate to freshwater. When chum salmon create breeding nests, they create a small depression in the gravel, which may cause mild effects on the physical habitat.

There is little or no evidence to support that Oncorhynchus keta has the potential for significant socio-economic impacts if introduced to the Great Lakes.

It has not been reported that Oncorhynchus keta poses a threat to human health or water quality. There is no evidence that this species negatively impacts infrastructure, economic sectors, recreational activities and associated tourism, or the aesthetic appeal of the areas it inhabits.

Oncorhynchus keta has the potential for high beneficial impact if introduced to the Great Lakes.

Oncorhynchus keta quality deteriorates as it develops for spawning, and those that are ready to spawn are not often sold in the US (Behnke 2010). In commercial fisheries, Oncorhynchus keta has a lower value than other salmon species such as chinook, coho, or sockeye salmon due to its low fat content and pale pink flesh that are not preferable to consumers. Oncorhynchus keta is usually caught from commercial fisheries to be canned. It is sometimes sold fresh or frozen under the name of “silver bryte salmon”.  Natives in Canada and Alaska eat chum salmon, as well as dry and smoke the fish to feed their dogs.

In Japan, it goes by the name “sake”, and is ranched there (Behnke 2010). Chum salmon meat is used in sushi and sashimi, and its eggs are used as well. Chum that have reached sexual maturity and have already spawned-out are harvested for their thick, tough skin to create salmon leather.

There are no known regulations for this species.*

*Ballast water regulations applicable to this species are currently in place to prevent the introduction of nonindigenous species to the Great Lakes via shipping. See Title 33: Code of Federal Regulations, Part 151, Subparts C and D (33 CFR 151 C) for the most recent federal ballast water regulations applying to the Great Lakes and Hudson River.

Note: Check federal, state/provincial, and local regulations for the most up-to-date information.

Control

Biological
There are no known biological control methods for this species.

Physical
There are no known physical control methods for this species.

Chemical
There are no known chemical control methods specific to this species. General piscicides (such as rotenone) may be used for control, but expect significant kill of non-target species.

Note: Check state/provincial and local regulations for the most up-to-date information regarding permits for control methods. Follow all label instructions.