Oncorhynchus tshawytscha (Fishes)

Species Description

The largest of all salmon, Chinook—or King—Salmon routinely weigh more than 40 pounds and can reach upwards of 120. Not surprisingly, Chinook prefer to spawn in bigger streams and rivers than other species, making their redds (a salmon "nest") in larger gravel and tolerating swifter flows than their smaller relatives.

Chinook Salmon are anadromous, which means they live part of their lives in saltwater, but begin and end their lives in fresh water streams. Chinook fry (a juvenile that is still developing in a stream) will spend anywhere between three months to two years in fresh water. Likewise, they will remain at sea from one to six years before making the run back to their home rivers to spawn.

The Endangered Species Act permits the federal government to protect imperiled species, subspecies, and distinct population segments. The term “distinct population segment” is a term of art that allows the government to protect portions of an entire species before a particular threat or population decline becomes so severe that the entire species is placed in jeopardy. For Pacific salmonids, the National Marine Fisheries Service has attempted to standardize how salmon populations are considered for protection by defining Evolutionarily Significant Units (ESUs) for each species of salmon. There are two federally protected Evolutionarily Significant Units of Chinook Salmon in the GGNP: the Central Valley Spring-Run ESU and the Sacramento River Winter-Run ESU. Both are transient in the Park, present only when they swim through the GGNP’s marine waters to and from the ocean and their natal spawning streams.

Click the image above for a larger range map for this species.

The Central Valley Spring-Run Chinook Salmon ESU once numbered more than 700,000 individuals. But by the late 1980s, the population declined to a handful of runs containing only a few hundred individuals. The remaining runs are only on small tributaries to the Sacramento River.

The Spring-Run Chinook require cool freshwater while they mature over the summer. In the hot Central Valley, summer water temperatures are only suitable above 150-500 m elevations. Unfortunately, most of this habitat is now upstream of impassable dams.

Because of its location in the Central Valley, pesticides are also a major concern for this ESU. Pesticides can affect the entire ecosystem that the salmon need to survive, and even cause male salmon to become feminized, i.e., affect the male salmon’s hormonal system in a way that may affect the male’s fecundity.

Moreover, biologists are concerned that the Feather River Hatchery has cross-bred different salmon populations, and now these hatchery fish are considered a major threat to the genetic integrity of the Central Valley Spring-Run Chinook Salmon ESU.

In 1999, this ESU was protected as a threatened species under the Endangered Species Act. This decision was affirmed in 2005.

Conservation Action Item

Reduce pesticide use:
Eat only local organic foods for a week

Chinook Salmon need cool, clean waters to reproduce successfully. Water diversions, dams, and water pollution are all lethal to their continued existence.

Help reduce the amount of pesticides poured into salmon habitats in the Central Valley. Eat local, organic foods for every meal for one week in 2010.

Big Year Competitors have reported 0 sightings and taken 0 actions to help this species recover so far this year.

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