FISHERY BULLETIN: VOL. 76, NO 1 



1962 through 1965, 30.9 million 1961-64-brood 

 fall Chinook salmon were marked at 12 Columbia 

 River hatcheries and one rearing pond. Four brood 

 years were marked to examine the differences be- 

 tween broods. A mark common to all 13 facilities 

 was used for each brood. Common marks were 

 applied to 21.3 million fish. To examine the differ- 

 ences between hatcheries, four hatcheries were 

 assigned special marks for each brood. Two hatch- 

 eries, Kalama River (in this study Kalama Falls 

 and Lower Kalama Hatcheries were treated as one 

 facility) and Spring Creek, had special marks for 

 all four brood years. Special marks were applied to 

 9.6 million fish. 



Sampling for these marked chinook salmon took 

 place from 1963 through 1969. Major marine sport 

 and commercial fisheries from southeastern 

 Alaska to central California and Columbia River 

 fisheries were sampled for marks, and scale sam- 

 ples were taken for age determination. Mark sam- 

 pling ranged from 14 to 28^^ of the catch, and age 

 sampling ranged from 1 to 47c by year. During the 

 7 yr of sampling, 3.3 million chinook salmon were 

 sampled for marks and 208,000 were sampled for 

 age. 



Returns to the 13 study facilities, adjacent 

 streams, and nonstudy hatcheries rearing fall 

 chinook salmon were sampled for marked 1961- 

 64-brood fish. Hatchery returns of these broods 

 numbered 155,800 fish, of which 8,500 were 

 marked. The stream sampling was conducted from 

 1964 through 1966 with 62,400 chinook salmon 

 examined and 1,600 marked fish found. 



Hatchery contribution estimation is dependent 

 on the validity of six assumptions. Where practi- 

 cal, these assumptions were tested with additional 

 studies and data collections. Assumption 1 (that 

 the marks were permanent) was tested by holding 

 marked fish in saltwater ponds for periodic 

 examination. Some regeneration did occur but, 

 since double and triple marks were applied, the 

 marked fish remained identifiable throughout 

 their life. Assumption 2 (that fish detected and 

 reported with the kinds of marks applied at the 

 hatcheries are hatchery fish) was tested by exam- 

 ining hatchery fingerlings and 1965-brood 

 chinook salmon catches for study marks. Over 30 

 million hatchery fingerlings were examined, and 

 only 201 missing ventral and 156 missing adipose 

 fins (none together) were found. The attempt to 

 keep 1965-brood chinook salmon from being 

 marked with study marks was unsuccessful. How- 

 ever, ocean and Columbia River catches of study 



marks were adjusted for those marks that ap- 

 peared to have a natural origin. Assumption 3 

 (fish were correctly aged from scales) was exam- 

 ined by having six scale readers from State, Pro- 

 vincial, and Federal agencies read 400 scales from 

 fish of known age. The readers correctly aged 83% 

 of the scales. Hatchery returns showed survival 

 adjustments had to be made for assumption 4 

 (equality of survival and maturity schedules for 

 marked and unmarked fish). Assumption 5 (the 

 equality of ocean distribution and catch vulnera- 

 bility of marked and unmarked fish) is supported 

 by ocean tagging studies showing similar dis- 

 tributions for marked and unmarked hatchery 

 fish. A 10-part sampler was used to select fish for 

 marking thus insuring the validity of assumption 

 6 (the marking of equal proportions of each hatch- 

 ery's production). 



Estimated catches of special marked fish from 

 the 10 special mark facilities ranged from 191 

 (Cascade, 1962 brood) to 4,406 (Spring Creek, 

 1964 brood). During the 7 yr of sampling, 65,620 

 common marked fish were estimated to have been 

 caught: 22,237, 1961 brood; 7,886, 1962 brood; 

 22,183, 1963 brood; and 13,314, 1964 brood. 



Columbia River hatchery fish were captured in 

 marine fisheries from Alaska to California. 

 Marine catches were primarily in British Colum- 

 bia and Washington fisheries. Fall chinook salm- 

 on from the Kalama River hatcheries had a more 

 northerly distribution than those from other spe- 

 cial mark hatcheries. Kalama fish had the highest 

 percentage catches of any special marked hatch- 

 ery chinook salmon in Alaska and British Colum- 

 bia fisheries. The average common marked fish 

 catch distributions in percent of the total chinook 

 salmon catch for the 1961-64 broods combined 

 were: 0.2, Alaska commercial fisheries; 33.7, 

 British Columbia commercial fisheries; 38.1, 

 Washington marine fisheries; 4.6, Oregon ocean 

 fisheries; 0.4, California ocean fisheries; and 23.1, 

 Columbia River fisheries. 



The potential contribution of Spring Creek 

 1961-64-brood fall chinook salmon ranged from 

 30,300 (1962 brood) to 165,200 (1964 brood) with 

 an average of 100,500 fish per brood. The average 

 catch to release ratio was 12 fish per 1,000 fish 

 released from Spring Creek. The Kalama hatch- 

 eries potential contribution ranged from 22,300 

 (1962 brood) to 56,800 (1961 brood) and averaged 

 43,100 fish per brood. The average catch to release 

 ratio for the two Kalama facilities was 9.6 fish for 

 each 1,000 released. Potential contributions at the 



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