STUDY OF AGE DETERMINATION BY HARD PARTS OF ALBACORE FROM 

 CENTRAL NORTH PACIFIC AND HAWAIIAN WATERS 



By Tamio Otsu and Richard N. Uchida, Fishery Research Biologists, U. S. Bureau of Commercial Fisheries 



gaged in similar studies and for others who may 

 work on this problem in the future. 



As part of the research program of the Pacific 

 Oceanic Fishery Investigations (POFI), Fish and 

 Wildlife Service, a study was initiated to determine 

 the age and growth of albacore, Germo alalunga 

 (Bonnaterre), occurring in the region of the 

 Hawaiian Islands and in the central North Pacific. 

 This study and other investigations of the albacore 

 resources of the Pacific are conducted by POFI 

 under Public Laws 329 (80th Congress) and 466 

 (Saltonstall-Kennedy Act, 83d Congress). 



Several workers have reported on the age and 

 growth of albacore as determined from surface 

 markings on the vertebral centra. Uno (1936a, b) 

 working with albacore taken by pole-and-line 

 fishing in the waters east of Cape Nojima, Japan, 

 made age determinations on 988 fish. Aikawa 

 and Kato (1938) reported on age determinations 

 of albacore based on 10 large fish taken near 

 Midway Island and 5 small fish taken off north- 

 eastern Japan. Partlo (1955) studied the age and 

 growth of the eastern Pacific albacore, utilizing 

 the vertebrae of 531 fish taken in 1950 from off- 

 shore waters adjacent to California, Oregon, 

 Washington, and British Columbia. Finally, 

 Figueras (1955) reported on age determination of 

 67 albacore taken off the coast of Galicia in 

 northwestern Spain. 



It was our hope to extend these findings to 

 include central North Pacific albacore and the 

 exceptionally large fish occurring in the Hawaiian 

 area. We assumed that methods employed in 

 other areas to determine the age of albacore 

 could be successfully employed in this study. 

 Our efforts in this respect were entirely unsuccess- 

 ful, however, as we were unable to verify or dupli- 

 cate findings of the other workers. It was our 

 conclusion that the markings on albacore hard 

 parts, particularly on the vertebrae, are not true 

 year marks, and therefore, cannot be used in the 

 aging of these fish. The results of our study, 

 though largely negative, are presented here for 

 the information of those who are presently en- 



Note.— Approved for publication Jan. 16, 1958. Fishery Bulletin 150. 



MATERIALS 



Scales and vertebrae were routinely collected 

 and certain other skeletal structures such as the 

 operculum and the fin spines were also examined. 

 Between January 1955 and July 1956, vertebrae 

 and scales were collected from 212 albacore 

 taken in Hawaiian waters and 53 from the central 

 North Pacific. 



Albacore taken by the Hawaiian longline fishery 

 from an area within 20 miles of the main islands, 

 were generally large, ranging in length from 93 

 to 128 cm. (weight, 33 to 93 lbs.) (fig. 1). These 

 fish were sampled at the two Honolulu auction 

 markets, the Hawaii Fishing Co., Ltd., and the 

 United Fishing Agency, Ltd., where the landings 

 of the Honolulu-based longline vessels were sold. 

 Albacore were obtained from the central North 

 Pacific on POFI's exploratory fishing cruises, 



Figure 1. — Length frequency of albacore from which 

 scales and vertebrae were colleeted. 



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