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

Life History
The Hood Canal summer-run Chum salmon are defined in the Salmon and Steelhead
Stock Inventory (WDF, WDW et al. 1993) as fish that spawn from mid-September to
mid-October. However, summer chum have been known to enter natal rivers in late
August. Fall-run chum salmon are defined as fish that spawn from November through
December or January. Run-timing data for as early as 1913 indicated temporal separation
between summer and fall chum salmon in Hood Canal (Johnson, Grant et al. 1997).
Hood Canal summer Chum salmon are genetically distinct from healthy populations of
Hood Canal fall Chum salmon originating within this area. Hood Canal summer Chum
salmon return to natal rivers to spawn during the August through early October period.
The fall Chum salmon spawn between November and December, when streams are
higher and water temperature is lower.
The time to hatching varies among populations and among individuals within a
population (Salo 1991). Fry tend to emerge when they had their best chances of
surviving in streams and estuaries (Koski 1975). A variety of factors may influence the
time to hatching, emergence from the gravel, or both. They include dissolved oxygen,
gravel size, salinity, nutritional conditions, behaviour of alevins in the gravel and
incubation temperature [reviewed in (Bakkala 1970; Schroder, Koski et al. 1974;
Schroder 1977; Salo 1991)]. The average residence time in estuaries for Hood canal
chum salmon is 23 days. Fry in Hood Canal have not been observed to display daily tidal
migrations (Bax 1983). Fry movement is associated with prey availability. Summer-run
chum salmon migrate up the Hood Canal and into the main body of Puget Sound. Fish
may emerge from streams over an extended period or juveniles may also remain in
Quilcene Bay for several weeks.
Status and Trends
Hood Canal summer-run Chum salmon were listed as threatened on March 25, 1999, and
reaffirmed as threatened on June 28, 2005 (70 FR 37160). Adult returns for some
populations in the Hood Canal summer-run Chum salmon species showed modest
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