** ** Species Identification and Age Determination of Pacific Salmon (Oncorhynchus spp.) by Scale Patterns Soto o I TO*  and Yukimasa IsHiDA* This paper summarizes methods used to determine the species and age of Pacific salmon (Oncorhynchus spp) by visual interpretation of characters on the scales of fish caught in the North Pacific Ocean and adjacent seas   Scale characters such as freshwater growth, radial striations, and shape and number of circuli are used to identify the species of Pacific salmon   Several illustrated keys for determination of f reshwater and ocean ages are included Key words: Pacific salmon, scale patterns, species identification, age determination 1972 1995 Anas (1963 2 3 77 1 11 1 1 2 (Koo,  1962;  Bilton et al.,  1964;  Mosher, 1972, Majoret al., 1972, Biman, 1960, , 1961; Taraka et al., 1969, Ishidaet al., 1989, Oguraet al., 1991) Mosher(1969)
1 Mosher
1972 1995 Anterior field Fig 1 Posteriar field Annulus Annuli (B) 1. (A) Circulus Circuli Table 1. Different systems to designate the age of Pacific
Freshwater growth zone Ocean growth zone 1A. 2A. (Fig 2A) 2B. 3A. 3B. 77 77
2 3 2
00 1 0.1 a 1B. 5A. Table 1
1.
33
.2 .3
.0 6A. 6B. 7A. 1 (Fig. 2D) 6 6 31.1% 596% 15.4% 37.8% 43.4%
(1) (p (3) (4) (5) (6) Fig 3F (1) 15 A, B (ユ
6 8 11 Fig 3B 2 3
(1) (2) Fig. 4-
Fig 4D, E (1) Fig. 8 A B 7.0% 03 01
0.5 133 1970 Fig. 4A 15 (4) (p 3 44 43.4% Ishida et al., 1993 Kæriyama, 1996 Fig 4C 1. 2 33 1. 71.9% 09% 27.2% Fig 10 .0 .1 Fig 16 71.9% 21 09% 27.2% 31 1.1 0.1 Fig.11 1 20   23 ao .1 59.6% 37.8% 4 621% 1. 35 1% Fig 12

31.1%
2 1.9% Fig 14 and Ishica, 1997 24.7% 1.8% Fig 15 1.3 22 Q .0 .5 .2 56 1% 15.8% 1.5%      .5 Q 1% . 1 .4
3 a 2 1. Q 45.4% 137% 3 4 Fig 17 .4 .0 .1 10.5%
44 35.5% 5.2% 56.3% .3
1% Ito .3 .0
(Mosher, 1972) 04 Q 2 1. 97.8% 03% 4 .1 .3 Fig 13 21 3 1 .2 .0 28% 2 3 1. (Salo, 1991)
Univ. Wash Publ. Fish NewSer. 1 Machidori, S., and F. Kato. 1984. Spawning populations and marine life of masu salmon (Oncorhynchus masou). Bull. Intern. North Pacific Fish. Comm., 43: 1-138. Major, R. L., K. H. Mosher, and J. E. Mason  1972 : Identification of stocks of Pacific salmon by means of scale features, p. 209-231. In R. C. Simon and P. A.  Larkin (eds.). The stock concept in Pacific salmon   H. R. MacMillan Lectures in Fisheries, Univ. B. C., Inst. Fish, Vancouver, B. C. Major, R. L., J. Ito, and H. Godfrey. 1978 : Distribution and abundance of chinook salmon in offshore waters of the North Pacific Ocean. Bull. Intern. North Pacific Fish. Comm., 38: 1-54. Mosher, K. H  1969 :  Identification of Pacific salmon and steelhead trout by scale characteristics. U.S. Fish Wildl. Serv. Circ., 317, 17pp. Mosher, K. H.  1972 : Scale features of sockeye salmon from Asian and North American coastal regions. Fish. Bull., 70: 141-183. Neave, F., T. Ishida, and S. Murai.  1967 : Salmon of the North Pacific Ocean. Part VI. Pink salmon in offshore waters. Int. North Pac. Fish. Comm. Bull., 22: 33p Ogura, M., Y. Ishida, and S. Ito.  1991 :  Growth variation of coho salmon Oncorhynchus kisutch in the western North Pacific.  Nippon  Suisan  Gakkaishi, 57:  1089-1093 Sandercock, F. K.  1991 : Life history of coho salmon (Oncorhynchus kisutch), p. 397-445  In C. Groot and L. Margolis (eds.) Pacific salmon life history. University of British Columbia Press, Vancouver, B.C. Salo, E. O. 1991 : Life history of chum salmon (Oncorhynchus keta), p. 231-309  InC. Groot and L. Margolis (eds.) Pacific salmon life history. University of British Columbia Press, Vancouver, B.C. Tanaka, S., M. P. Shepard, and H. T. Bilton  1969 : Origin of chum salmon ( Oncorhynchus  keta )  in offshore waters of the North Pacific in 1956-1958 as determined from scale studies.  Bull.  Intern.  North Pacific Fish. Comm, 26: 57-155. 2   (A)
  (G)
 (H) (C) (日) c 1 A 5 B 2   3 D (B) c (D) (E) 2 (C) 3 (D) .3 .4 1970 1994 (A) (B) (C) A B (A) 2 (B) 3 (C) 4 on a (A) 1. (B) 2 (C) .2. (C) .3 (D) .4 (E) 1. (A) 2 (B) (C) (D) .2 .3 (D) .4 (日.5