It must further be understood that hatchery meth- 

 ods ha\-e chano-ed significantly since 1962. This 

 change is reflected in the increased size of fish re- 

 leased from hatcheries. For examjde, the average 

 weight of fall chinook salmon released from Co- 

 huui)ia Kiver hatcheries operated by Washington 

 Department of Fisheries increased from 2.18 g. in 

 19(i2 to 3.89 g. in 19(50.'" It is likely, therefore, that 

 survival of hatchery lisli and, hence, the contribu- 

 tion of given numbers released has changed since 

 1962. 



To estimate the value of the catch of 1961-brood 

 fall chinook salmon from all Columbia River 

 hatcheries, we must assume that the o.86 million 

 fish released from hatcheries not included in the 

 study coutiubuted to the fisheries in the same pro- 

 portion as the fish released {y-jX)^> million) from 

 the hatcheries mider study. On this basis the value 

 of the catch of these releases would be: 



(3.86) (1,917,003) 



137,832=^ '\..,, - 



( o3.b5 ) 



or about $138,000. The \alue of the catch of fish 

 released from all hatcheries is then estimated as 

 $2.0."i.'..000. 



Because of the conservati\e nature of tlie esti- 

 mate of survival of marked lish relative to un- 

 marked fish, we believe that the estimated value 

 of the catch of hatchery fish, as well as the bene- 

 fit-cost estimate presented abo\e, is minimal. 



SUMMARY 



1. During i years of marking at 12 hatcheries, 

 21.3 million fish (10 percent of the total produc- 

 tion of 213 million) were marked with an adi- 

 pose-nnixillary mark. An additional 9.6 million 

 were identified with special marks unique to a 

 hatchery. 



2. The 1961-brood release of 53.6 million fish 

 included 5.4 million (10.1 percent of the total re- 

 lease) marked with a "connnon mark" (Ad-RM). 

 Fish with marks unique to a hatchery were re- 

 leased from Elokomin, Kahuna, Oxbow, and 

 Spring Creek Hatcheries. 



3. Auxiliary data collected suggested that the 

 quality of marking and the permanence of marks 

 (except possibly for the maxillary mark in the 

 1961 and 1962 broods) were reasonably satisfac- 

 torv. 



1^ Harry Senii, Washington Stati^ Dppartniont of Fisheries (per- 

 sonal commnnication ). 



4. During the first 4 years of mark sampling 

 ( 1963-66), an average of 23 percent of the chinook 

 salmon catch was examined for nuirked fish. 



5. P^xcept for 1963, sampling for marked fish 

 was conducted in most chinook fisheries from Mon- 

 terey, Calif., northward to southeast Alaska. In 

 1963, sampling was limited to the Washington, 

 Oregon, and Columbia River fisheries. 



(). A total of 9,573 nuirked fish from the 1961 

 brood of possible Columbia River hatchery origin 

 were reco\ered during the 4 years. The majority, 

 (),189, were recovered as age-3 fish in 1964. 



7. Although marked fish were recovered in the 

 ocean fisheries over the entii-e range of sampling, 

 most were recovered from landings made north of 

 the Columbia River mouth (Washington and west 

 coast of Vancouver Island fisheries) . 



S. Marked fish that originated from Kalama 

 Hatchery were the only ones (specific to a liatch- 

 ei-y) recovered in the southeast Alaska fishery. In 

 general, proportionately more of the Kalama fish 

 were recovered in tlie northern parts of the sam- 

 pling range than were the marked fish originating 

 from Elokomin, Oxbow, or Spring Creek Hatch- 

 eries. 



9. An estimated total of 21,600 marked (Ad- 

 RM) fish that originated from the 12 study hatch- 

 eries were caught. An additional 3,400 escaped the 

 fisheries and returned to spawn. 



10. The estimated average catch to escapement 

 ratio for the hatcheries under study was about 

 6:1. For nuu-ked fish from Elokomin, Kalama, 

 Oxbow, and Spring Creek Hatcheries this ratio 

 was 12 :1, 9 :1, 3 :1, and 7 :1, respectively. 



11. The catch of Ad-RM marked fish from all 

 12 hatcheries in terms of the numbers released was 

 ;',.!)7 per 1,000 released. This quantity was 4.50 and 

 3.78 for Kalama and Spring Creek Hatcheries, 

 respectively. The contribution per 1,000 released 

 for Elokomin and Oxbow Hatcheries was at most 

 only one-half that for Kalama and Spring Creek. 



12. By assuming that marked and unmarked 

 hatiheiv fish have the same ocean distribution and 

 maturity schedules and that survival of marked 

 fish was 70 percent of the survival of unmarked 

 fish, we estimated that the total catch of hatchery 

 fish (marked and uiunarked) was 287,326. 



13. The estimated catch, 287,326, of hatchery 

 fish comprised about 10 percent of the total catch 



COXTRIBUTIOX OF COLUMBIA RIVER HATCHERIES TO FAI,L CHINOOK SALMON" HARVEST 



387 



