The \-2 liatcheries are distrilnited over sibout -250 

 km. (155 miles) of the Cohinibia Kiver (t\ix. 1). 

 Hi<j ("reek Hatchery, the lowermost station, and 

 Klickitat Hatchery, the uppermost, are on trib- 

 utaries about 40 and 290 km. (25 and LSO miles), 

 respect i\ely, above the river mouth. Some hatch- 

 eries (Bonneville, Cascade, Oxbow, Little White 

 Salmon, and Spring Creek) are adjacent to the 

 Columbia River and release their fish directly into 

 the ri\er. In contrast, fish released at Klickitat 

 Hatchery nmst travel about 40 km. (2.-) miles) to 

 reach the main stem of the Columbia. 



Artificial [)ropagation procedures are similar at 

 all hatcheries raising fall chinook salmon. Adults 

 normally return to these hatcheries and are 

 spawned during Seijtember and October. Depend- 

 ing ujjon water temperatures, fry tyijically reach 

 the free swinnning stage in February or March 

 and are tlien placed in ponds. The young fish are 

 released from the hatchery 90 to 120 days later at 

 an average length of (i to S cm. (2-o inches). Dur- 

 ing tlie following 5 years, they are availabh' to 

 connnert'ial and sport fisheries from soutlieast 

 Alaska to central ( "alifornia. Some fish mature and 

 return to the ( 'oluini)ia Ki\er during t heir second, 

 tliird, fourtii, and fifth years; ho\ve\er, most are 

 in their third (age 3) and fourtli years. 



This report (1) describes the design of the 

 marking experiment and (2) presents an estimate 

 of the contribution (catch) to tlie fisheries i)y the 

 1961-brood hatchery releases and an estimate of 

 the benefit-cost ratio. This is the first basic analysis 

 of data collected under the hatchery evaluation 

 study directed by Paul D. Zimmer of the Columbia 

 River Fishery De\elopment Program. Se\eral re- 

 search laboratories and individuals are analyzing 

 data from tliis study and will develop nuicli addi- 

 tional information. 



DESIGN OF EXPERIMENT TO ESTIMATE 

 HATCHERY CONTRIBUTION TO FISH- 

 FRIES 



The general approai-h for estimating the hatch- 

 ery contribution of fall chinook salmon was to 

 identically mark the same fraction (about ID per- 

 cent) of eacli hatchery's production and then sam- 

 ple for this mark in tlie commercial and sport 

 fisheries. From the numiier f)f marked fish recov- 

 ered and the sampling ratio, togetlier with the 

 fraction originally marked ( or expected marked to 

 unmarked ratio), we can estimate the number of 

 hatchery-reared fall chinook salmon in the catch. 

 In addition to the "conunon mark" (i.e., mark aj)- 

 plied to portion of fish at all hatcheries under 

 study), "special marks'' were used at selected 

 hatcheries each year to examine the variations in 

 contribution among hatidieries. Supplemental data 

 were also collected in an attempt to explain the 

 ex[)ected \ariati()ns among hatcheries and to test 

 some of the assvimptions underl\'ing the experi- 

 mejital teclmiques and estimating procedures. 



The success of the marking experiment required 

 the efforts of many f)eople and the cooperation of 

 fisher}- agencies on the Pacific Coast ( table 1 ) . All 

 marking and mark reco\-ery activities were under 

 the direct supervision of experienced biologists. 



MARKING 



The marking [)hase of the stutly ijegan in June 

 19()2 and was completed in .rune 19G5. The 1961- 

 64 ])roods (progeny of adults that spawned in 

 lyOl, 19(i2, 196:3, and 1964) were marked. The 

 "common mark"' consisted of removing the adipose 

 fin and a [>ortion of tlie right or left maxillary 

 l)one. The cli])ped right maxillary was used to 

 identify the 196 f and 196.S ln-(X)ds and the clipped 

 left maxillary the 19(i2 antl 1964 lu'oods (table 2). 



Table 1. — Responsibilities of agencies participating in the marking and mark recovery phases of the Coliimbia River fall 



chinook hatchery contribution study, 1962-68 



Suijervisiou 



-\geiicy 1 



Cooidiiiating and supervising Biologist Biologist... BCF 



Obtaining fisll loi- ]iiaiking llatcheiv personnel. Biologist and liatclicry manager VVUF, FCO. HSFW 



Marking .- Fish markers... Biologist WDF. Ft'O. BSFW 



Sampling hatehery releases Hatchery personnel. Biologist and hatcliery manager WDF'. FCO, BSFW 



Samphnp catch for marked fish Mark samplers Biologist ADFO, FRBC. WDF, FCO 



OOC.CFO. BCF 



Sampling hatchery returns and natural do do WDF, FCO, BSFW 



spawning populations for marked fish. 



' ADFG— .\laska Dept. of Fish and Game; FRBC— Fisheries Research Board of Canada; WDF— Washington Dept. of Fisheries; FCO— Fish Commis- 

 sion of Oregon; OOC— Oregon Game Commission; CDFO— California Dept. of Fish and Game; BCF— Bureau of Commercial Fisheries; BSFW— Bureau of 

 Sport Fisheries and Wiidlife. 



CONTRIBUTION OV COLUMBIA KIVEK HATCHERIES TO FALL CHINOOK SALMON HARVEST 



;j63 



