Carbaryl, Carbofuran, and Methomyl - National Marine Fisheries ...

Table 9. UCR Chinook salmon - preliminary population structure, abundances, and
hatchery contributions (Good, Waples et al. 2005).
Population
Historical
Abundance
Most Recent
Spawner
Abundance
Hatchery
Abundance
Contributions
Methow River ~2,100 79-9,904 59%
Twisp River Unknown 10-369 54%
Chewuch River Unknown 6-1,105 41%
Lost/Early River Unknown 3-164 54%
Entiat River ~380 53-444 42%
Wenatchee River ~2,400 119-4,446 42%
Chiwawa River Unknown 34-1,046 47%
Nason Creek Unknown 8-374 39%
Upper Wenatchee River Unknown 0-215 66%
White River Unknown 1-104 8%
Little Wenatchee River Unknown 3-74 21%
Total ~4,880 (min)
Life History
UCR spring Chinook salmon begin returning from the ocean in the early spring. They
enter the upper Columbia tributaries from April through July, with the run into the
Columbia River peaking in mid-May. After migration, UCR spring Chinook salmon hold
in freshwater tributaries until spawning occurs in the late summer, peaking in mid- to late
August. Juvenile spring Chinook salmon spend a year in freshwater before emigrating to
salt water in the spring of their second year.
Status and Trends
UCR spring-run Chinook salmon were listed as endangered on March 24, 1999 (64 FR
14308). This listing was reaffirmed on June 28, 2005 (70 FR 37160) based on a
reduction of UCR spring-run Chinook salmon to small populations in three watersheds.
Based on redd count data series, spawning escapements for the Wenatchee, Entiat, and
Methow rivers have declined an average of 5.6%, 4.8%, and 6.3% per year, respectively,
since 1958.
77