The limited number of marks available pre- 

 cluded individual hatchery comparisons as 

 made from data of the fall chinook salmon 

 study (Cleaver. 1969b; Worlund. Wahle, and 

 Zimmer. 1969; Lander, 1970; Henry, 1971). 

 The size of fish at release reflects partially the 

 differences in rearing techniques. In both wild 

 and hatchery salmon stocks, it is well known 

 that large smolts survive better and contribute 

 more to catches, other factors being reasonably 

 equal, than do small smolts (Ricker, 1962; 

 Fredin, 1964; Johnson, 1970). The average size 

 of fish in releases varied considerably between 

 hatcheries, somewhat between river sections, 

 and slightly between broods. Again, the limited 

 number of marks prevented evaluation of the 

 effect of size at release on contribution, but 

 average weights are included to complete the 

 data record (Appendix Tables la and lb). 



FISHERY BULLETIN: VOL. 72. NO. 1 



Estimating Procedures 



Simple numerical examples explain the basic 

 estimating procedures. A more formal account 

 was reported in the chinook salmon study 

 (Worlund, Wahle, and Zimmer, 1969). 



The first quantities to be estimated were the 

 numbers of marked and unmarked fish in hatch- 

 ery releases. This was done with data from a 

 10-part sampler (see "Marking and Release 

 Procedures"). The device was precalibrated 

 from a number of trials with known numbers of 

 fish to find the average number and percentage 

 retained by a single closed pocket. The follow- 

 ing example illustrates the fish enumeration 

 procedure. Suppose a precalibrated pocket is 

 found to remove a 10.1% sample. Also, suppose 

 after passing all the fish in a pond through the 

 sampler, the number of fish retained by the 



Table 1.^ — Grouping of Columbia River hatcheries participating in study and 

 type of mark assigned to each group. 



River section and hatchery- 



.1/ 



Hatchery location 



KLaskanine (FCO) 

 Grays River (WDF) 

 Big Creek (FCO) 

 Elokomin (WDF) 



Klaskanine River 



Grays River 



Big Creek, Columbia River 



Elokomin River 



Middle River (Cowlitz River to Bonneville Dam) 



Toutle (WDF) 

 Lower Kalama ( WDF ) 

 Kalama Falls (WDF) 

 Lewis River (WDF) 

 Speelyai (WDF) 

 Sandy (FCO) 

 Eagle Creek (FCO) 

 Washougal (WDF) 

 Bonneville (FCO) 



Green River, Toutle River 



Hatchery Creek, Kalama River 



Kalama River 



Lewis River 



Speelyai Creek, Lewis River 



Cedar Creek, Sandy River 



Eagle Creek, Clackamas River 



Washougal River 



Tanner Creek, Columbia River 



Upper River (Bonneville Dam to The Dalles Dam) 



Cascade (FCO) 



OxBow (FCO) 



Carson (BSFW) 



Little White Salmon (BSFW) 



Willard (BSFW) 



Klickitat (WDF) 



Eagle Creek, Columbia River 

 Herman Creek, Columbia River 

 Tyee Springs, Wind River 

 Little White Salmon River 

 Little White Salmon River 

 Klickitat River 



Uppermost River' (above The Dalles Dam) 



Leavenworth (BSFW) Icicle Creek, Wenatchee River 



Mark 



2/ 



Lower River (Columbia River mouth to Cowlitz River) 



Ad-RM 



Ad only 



Ad-LM 



D-Ad 

 D-Ad-LM 

 D -Ad-RM 



1/ Acronyms designate the following agencies: FCO = Fish Commission of 

 Oregon, WDF - Washington Department of Fisheries, and BSFW = Bureau of 

 Sport Fisheries and Wildlife. 



2/ Ad = adipose fincllp, D = dorsal flnclip, LM = left maxillary bone 

 clip, and RM = right maxillary clip. 



142 



