fin) . E\ en wliere the regeneration « us greater (ui) 

 to (i j)ercent of the fish examined), the marks were 

 readily identifiable owing to a deformation of the 

 fin rays. 



The maxillary mark completely regenerated for 

 varying ijroi)ortions of the groups examined. The 

 relatively high occurrence of regeneration for the 

 lOfil- and li)(;2-l)rood fish (().!)-ll.() percent) was 

 the basis for removing more of the maxillary bone 

 for the next 2 brood years. Only llie tip of the 

 maxillary was removed for the llMil and iy()2 

 broods. For the V.H>:'> and I'.MU broods, the maxil- 

 lary was excised at a ]ii)int below the muldle of 

 the eye. This change in marking procedure is 

 reflected in the smaller percentages of fish with 

 regeneration (l-.'i percent) for the I'.X;.'} and 1Ih;4- 

 brood fish. 



It is likely that these test fish were examined in 

 greater detail and under better conditions than 

 can be expected in actual sampling. The results of 

 the examinations, howe\er, make it doubtful that 

 fin regeneration is an important source of error 

 in the total program. Maxillary regeneration 

 causes some ditticulties and will be considered in 

 a later section. 



MARK RECOVERIES AND ESTIMATED 

 CATCH OF MARKED FISH 



The mark-sampling phase of the program began 

 in ldi)'-\ when the 1961-bi'ood-year iisli first entered 

 some of the fisheries as 2-year-olds. During the 

 first year, sampling was limited to the Washington 

 and Oregon ocean fisheries, Columbia River fish- 

 eries, and hatchery returns, l^eginning in 19t)4, 

 samj)ling was expanded to include most chinook 

 salmon fisheries from Monterey, Calif., to and in- 

 cluding southeast Alaska. The results reported 

 here concern recoveries of the 19fil brood in li)(>;>, 

 1064, 1965, and 1966. Recoveries from this brood 

 in 1967 were minor. 



The total catches of chinook salmon in the fish- 

 eries that were sampled and luuubers of fish ex- 

 amined each year for marks and for age are gi\en 

 in table 6. Over the 4 years of sampling, 2li per- 

 cent of the catch of 8.5 million fish were examined 

 for marks. In addition, 1.5 percent of the total 

 catch was sampled for age determinations and 

 other data (e.g.. length and weight). Mark sam- 

 pling percentages were SS.;'), 26.6, 19.8, and 21.5 

 percent for 196r,, 1964, 1965, and 196(), resi)ectively. 



nT4 



Table 6. — Catches of chinook salmon and number of fish 

 examined for marks and age, 1963-66 



Catcll • Chinook salmon Sampled Sampled 



Year for marks for age 



1961 brood All ages 



- ..Number offish 



1963 41,786 670.172 161.460 20,000 



1964 -.. 1,566,549 L',671,976 709,660 33,000 



1965 998,849 2,572,919 508,730 34,000 



1960 206,765 2,645,537 569,265 40,000 



Total -- 2,812,949 8,460,604 1,949,116 127,000 



• Total catch is only for those fisheries sampled. 



RECOVERIES OF MARKED FISH 



Table 7 summarizes all marks of jiossible Co- 

 lumbia River liatchery origin (1961 brood year) 

 recovered in the fisheries. Included in the table 

 are recoveries of marks that could be the result of 

 maxillary regeneration. A total of 9.57?) marked 

 fish of possible Columbia River hatchery origin 

 were recovered during the 4 years of sampling. 

 AltlKiiigh fairly large numbers of marked fish of 

 the 19(;i brood were recovered in 1966 and during 

 the limited sampling in 196;>, most of them were 

 reco\ered as 3-year-old fish in 1964. Exceptions 

 were the fisli marked at Kalama Hatchery: slight- 

 ly more of the.se fish were recovered in 1965 than 

 in 1964. 



The distribution of recoveries for each year by 

 region of capture and type of fishery is shown in 

 table 8. Only recoveries of the full mark.s are 

 listed. The distribution of recoveries of the pos- 

 sible experimental marks was similar. 



As 2-year-old fish, those with 1961-brood marks 

 were re^'overed only in the Washington ocean 

 sport and Columbia Ri\er gill net fisheries. Al- 

 though many fisheries were not sampled in 1963, 

 2-year-old mark recoveries of the 1962- and 1963- 

 brood fish indicate that the contribution of this 

 age group to other fisheries is relatively minor. By 

 1964 the marked fish were distributed over the 

 entire range of sam]iling. For ocean fisheries tliey 

 ai>|)eared most frecpiently, however, in Wasliing- 

 ton and British Columbia catches (although not 

 shown in table 8. the bulk of the British Columbia 

 recoveries were from the troll fishery landings on 

 the west coast of Vancouver Island) . Tlie distribu- 

 tions of recoveries in 1965 and 1966 were similar 

 to 1964 but in fewer numbers. 



The distributions of marked fish that originated 

 from Spring Creek and Kalama Hatcheries were 

 different. Proportionately more of the Kalama 



T'.S. FISH AXn WH>I)LIFE SERVICE 



