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Adult Holding Habitat 



Holding habitat is the freshwater area used by adult spring Chinook and summer 

 steelhead while waiting to spawn. Spring Chinook holding has been documented 

 in the Skookumchuck from the dam down to Bucoda, in the South Fork and main 

 stem Newaukum at least downstream to Mile 4, and the main stem Chehalis at 

 least downBtream to the vicinity of Adna (Hiss et aj . 1983a), based on 

 underwater visual observations. Some holding must alao occur in the main stem 

 Chehalis between Chehalis and Oakville, based on occurrence of adult Chinook 

 in fish kills (Gene Deechamps, Chehalis Tribe, pers. comrn.). Quantity of 

 habitat has not been studied, but is presently being documented during the FWS 

 habitat surveys. 



Spawning Habitat 



Location of accessible streams and occurrence of spawning spring Chinook, fall 

 Chinook, coho, and chum are listed in the "Stream Catalog" (Phinney et ai . 

 1975). However, more recent spawner surveys have led to some extensions and 

 deletions of actual spawning grounds, for example in the case of spring 

 Chinook (Hiss et ai . 1985). Steelhead spawning grounds are listed by stream 

 and available miles for the entire watershed in WDW unpublished files. 

 Extent of utilization is estimated annually in spawning ground surveys for 

 spring Chinook, fall chinook, coho, chum, and winter steelhead. Summary 

 escapement data for the Basin was presented in Chapter 3. Sea-run cutthroat 

 trout and a few Dolly Varden char can be expected to migrate at least as far 

 upstream to spawn as steelhead and coho, but agencies do not estimate their 

 escapement. American shad may spawn as far upstream as Rainbow Falls, and 

 white sturgeon as far as Centralia, but this is known only from chance 

 encounters, not systematic observation. Total habitat accessible to 

 anadromous fish will be documented during the FWS habitat surveys, as will the 

 extent of spawning gravel for Chinook. 



Juvenile Rearing Habitat 



Freshwater Rearing 



Generally, salmonids can be expected to rear at least as far upstream as they 

 spawn, and, for species rearing in summer, disperse as far downstream as high 

 temperatures permit. Juvenile chinook salmon emerge from the gravel in March, 

 and some remain in freshwater until October but virtually all migrate to 

 saltwater by the end of summer (WDF 1971). Coho emerge from the gravel in 

 March and April, and rear in freshwater for one year. Quantity of summer 

 rearing habitat for coho has been roughly estimated for use in setting 

 habitat-based escapement goals (Stone, WDF, pers. comm. ) . However, smolt 

 trapping studies (Seller 1987) indicate that coho escapement could be larger 

 than those based on coho habitat quantity. One possible explanation is that 

 there is much more habitat than indicated in the stream catalog (Phinney at 

 ai. 1975). Quantity of summer rearing habitat for steelhead has been roughly 

 estimated for use in setting habitat-based escapement goals (WDW unpublished 

 files). 



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