EPA's Vessel General Permit and Small Vessel General

11. Certain park pest management activities (§ 223.203(b)(11))
12. Certain municipal, residential, commercial, and industrial development and
redevelopment activities (§ 223.203(b)(12))
13. Forest management activities on State and private lands within the State of Washington
(§ 223.203(b)(13))
14. Activities undertaken consistent with an approved Tribal resource management plan (§
223.204).
Chinook Salmon
Description of the Species
Chinook salmon are the largest of the Pacific salmon and historically ranged from the Ventura
River in California to Point Hope, Alaska in North America, and in northeastern Asia from
Hokkaido, Japan to the Anadyr River in Russia (Healey 1991). We discuss the distribution,
status, and critical habitats of the nine species 3 of endangered and threatened Chinook salmon
separately, and summarize their common dependence on Waters of the U.S. However, because
listed Chinook salmon species are virtually indistinguishable in the wild and comprise the same
biological species, we begin this section describing those characteristics common across ESUs.
Chinook salmon exhibit one of the most varied and complex life history strategies. The “streamtype”
of Chinook salmon resides in freshwater for a year or more following emergence and the
“ocean-type” migrates to the ocean within their first year. The ocean-type typifies populations
north of 56ºN (Healey 1991). The life cycle of all Chinook salmon spans fresh and marine
waters. Spawning migrations generally occur in the spring and fall; spawning typically occurs
earlier in the spring/summer at northern latitudes and later in southern latitudes (Healey 1991).
Temperature and stream flow can significantly influence the timing of migrations and spawning,
as well as the selection of spawning habitat (Geist et al. 2009, Hatten and Tiffan. 2009). Chinook
salmon are semelparous (i.e. they die after spawning).
While in fresh water, juvenile Chinook salmon are often found in the lower reaches of a river
near its estuary in areas of low water velocity. As they grow, they tend to move to deeper waters
where the velocity is higher (Healey 1991). Generally, Chinook salmon outmigrants (smolts) are
about 2 to 5 inches long when they enter saline (often brackish) waters. The process of
smoltification enables salmon to adapt to the ocean environment (Wedemeyer et al. 1980).
Several factors can affect smoltification process, not only at the interface between fresh water
and salt water, but higher in the watershed as the process of transformation begins long before
fish enter salt waters. These factors include exposure to chemicals such as heavy metals and
elevated water temperatures (Wedemeyer et al. 1980).
3 We use the word “species” as it has been defined in section 3 of the ESA, which include “species, subspecies, and any distinct
population segment of any species of vertebrate fish or wildlife which interbreeds when mature (16 U.S.C. 1533)”. Pacific
salmon that have been listed as endangered or threatened were listed as “evolutionarily significant units (ESU)” which NMFS
uses to identify distinct population segments (DPS) of Pacific salmon. Any ESU or DPS is a “species” for the purposes of the
ESA.
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