FISHERY BULLETIN: VOL. 76. NO. 1 



generation. This belief is also supported by the 

 absence of Ad-LV and Ad-RV marks in the 1965- 

 brood catches of chinook salmon (Bureau of Com- 

 mercial Fisheries^' ''• ^; Fish Commission of Ore- 

 gon^). The Ad-V marks were not assigned to the 

 1965-brood fish. Thus, we have claimed all Ad-RV, 

 Ad-LV, and Ad-only marked chinook salmon as 

 hatchery fish. 



However, the percentage occurrence of SV 

 marks in the fisheries was much higher than 1 ) the 

 maxillary regeneration rate, 2) the occurrence of 

 Ad-SV marks in the fisheries, and 3) the occur- 

 rence of SV marks in hatchery returns. Thus, we 

 concluded SV marks occurred because of maxil- 

 lary regeneration and natural marks. 



Two steps were required to determine the 

 number of SV marked fish we would claim as part 

 of the hatchery production. First, we assumed the 

 maxillary regeneration rate for all special marked 

 hatcheries was the same. The partial mark per- 

 centages for Kalama River and Spring Creek com- 

 bined were calculated for each fishery, year, and 

 brood. For example, in the 1964 Washington 

 commercial fisheries the estimated catch of 1961- 

 brood Ad-LV-RM and Ad-RV-RM full marked fish 

 was 1,001 and Ad-LV and Ad-RV partial marked 

 fish was 232. The partial mark percentage for this 

 year, fishery, and brood was then 232/1,001 = 

 23%. 



Second, full mark recoveries from other special 

 mark hatcheries (Elokomin, OxBow, Grays River, 

 Cascade, Klickitat, Big Creek, Bonneville, and 

 Little White) for the corresponding brood, year of 

 recovery, and fishery were multiplied by the 

 Kalama-Spring Creek percentages. For example, 

 the estimated full mark recoveries of Elokomin 

 and OxBow 1961-brood chinook salmon in the 

 1964 Washington commercial fisheries were 48 

 and 58 fish respectively. The SV marked fish 

 claimed as part of Elokomin and OxBow hatch- 



*Bureau of Commercial Fisheries. 1969. Data report: Colum- 

 bia River fall chinook salmon hatchery contribution study; 1967 

 sampling season. Unpubl. manuscr., 519 p. U.S. Fish Wildl. 

 Serv., Bur. Commer. Fish., Seattle Biol. Lab. 



'Bureau of Commercial Fisheries. 1970. Data report: Colum- 

 bia River fall chinook salmon hatchery contribution study: 1968 

 sampling season. Unpubl, manuscr., 437 p. U.S. Fish Wildl. 

 Serv., Bur. Commer. Fish., Seattle Biol. Lab. 



^National Marine Fisheries Service. 1971. Data Report: Co- 

 lumbia River fall chinook salmon hatchery contribution study: 

 1969 sampling season. Unpubl. manuscr., 283 p. Natl. Mar. Fish. 

 Serv., Seattle Biol. Lab. 



"Fish Commission of Oregon. 1972. 1970 fin-mark sampling 

 and recovery report for salmon and steelhead from various 

 Pacific coast fisheries. Unpubl. manuscr., 102 p. Fish Comm. 

 Oreg., Biom. Sect., Clackamas. 



eries' production were then 48 x 0.23 = 11 and 58 

 X 0.23 = 13 respectively. In cases where the calcu- 

 lated claimed partial marks were greater than the 

 partial marks actually recovered, all partial 

 marked fish were claimed. No SV marked fish 

 were claimed for the southeastern Alaska or 

 California fisheries because few Columbia River 

 hatchery special marked fish were captured in 

 these fisheries. 



The claimed partial marked fish estimates by 

 year and fishery were summed for each special 

 mark hatchery. The sums are the number of par- 

 tial marked fish we claimed as part of the special 

 mark hatcheries' catch (Table 3). 



Loss of maxillaries due to hooking occurred dur- 

 ing the ocean lives of the marked fall chinook 

 salmon (author's pers. obs. ), resulting in the possi- 

 ble misidentification of marks. In some cases a 

 marked chinook salmon was assigned to a certain 

 brood year from scale analysis, but the fish had the 

 wrong maxillary mark for that brood. For exam- 

 ple, 1961-brood Ad-LM marked chinook salmon, 

 1962-brood Ad-LV-RM marked fish, 1963-brood 

 LV-RM marked chinook salmon, and so on (see 

 Table 1 for correct marks for each brood) were 

 reported to have been caught in the fisheries. In 

 some cases, double maxillary marks (1961-brood 

 Ad-RM-LM, 1963-brood Ad-LV-RM-LM, etc.) 

 were reported to have been caught. 



Duplication of marks or use of marks with the 

 opposite maxillary for the same brood year were 

 prevented by the Pacific Marine Fisheries Com- 



TABLE 3.— Estimated catches of 1961- to 1964-brood fall chinook 

 salmon from Columbia River study hatcheries with full marks, 

 misidentified marks, partial marks, and partial marks claimed 

 as study hatchery fish by brood and hatchery. 



' Double maxillary clips or the opposite maxillary for a particular brood year. 



184 



