Seafood Watch

Seafood Watch® Wild Pacific Salmon Report October 8, 2010
ESUs
As of June 2004, four ESUs of chum salmon had been identified by NMFS in the contiguous
United States:
• Hood Canal Summer-run
• Columbia River
• Puget Sound/Strait of Georgia
• Pacific Coast
Of these four, the first two ESUs are listed as Threatened Species under the Endangered Species
Act. Both threatened ESUs are supported by NMFS Critical Habitat Designation (NMFS 2004a).
The designation provides notice to federal agencies and the public that the chum areas are vital to
conservation.
In Alaska, chum salmon are not divided by ESUs. Instead, state salmon fishery management is
divided into four overarching regions: Southeast Alaska, Central Region, Westward Region, and
Arctic-Yukon-Kuskokwim Region. In Alaska, chum salmon are predominantly harvested in
Southeast Alaska and Alaska’s Central Region (Plotnick and Eggers 2004).
Life History Traits
Chum salmon are anadromous, semelparous, and spawn primarily in fresh water. Chum salmon
grow to be among the largest of Pacific salmon, second only to Chinook salmon in adult size,
with individuals reported over a meter in length and greater than 20 kg in weight. Average size
for an adult chum is 3 to 9 kg (Buklis 1994, NMFS 2001b).
The species is best known for the enormous canine-like fangs and striking body color (a calico
pattern, with the anterior two-thirds of the flank marked by a jagged, reddish line and the
posterior third by a jagged black line) of spawning males. Females are less boldly colored and
lack the extreme dentition of the males (NMFS 2001b).
Most chum salmon mature between ages two and five, with 60-90% of fish maturing at four
years of age (particularly in southeastern Alaska, though there is variation in maturation rates
between streams) (Buklis 1994). Age at maturity appears to follow a latitudinal trend in which a
greater number of older fish occur in the northern portion of the species’ range. The maximum
age reported for chum salmon is six years (Froese and Pauly 2004).
Chum salmon tend to spawn in the lowermost reaches of rivers and streams, typically within 100
km of the ocean. That said, some chum in the Yukon River travel over 2,000 miles to spawn in
the Yukon Territory. Buklis (1994) notes: “Chum salmon often spawn in small side channels and
other areas of large rivers where upwelling springs provide excellent conditions for egg survival.
They also spawn in many of the same places as do pink salmon, i.e., small streams and intertidal
zones.” Fecundity for female chum normally ranges between 2,400 and 3,100 eggs. The
semelparous fish cease feeding on their return freshwater migration.
After hatching, chum salmon migrate almost immediately to estuarine and ocean waters, in
contrast to coho, Chinook, and sockeye salmon, which migrate to sea after months or years in
freshwater. Migrating chum form schools in estuaries, presumably to reduce losses to predation,
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