single catch of 42 albacore made daring 

 the first winter of fishing. As evidenced 

 by Japanese catch data, substantial nunn- 

 bers of albacore were present as far west 

 as 141 °E. longitude during the winter of 

 1953-54. 



10. 



2. Trolling for albacore was most successful 

 during the fall survey, with the highest 

 catch of 8,8 albacore per 10 line-hours 

 of trolling made at 42 N, , 172 E. Troll- 

 ing during both winter surveys was poor. 

 No albacore were taken during the first 

 winter and only 4 during the second winter 

 of fishing. 



3. The albacore population moves north and 

 south seasonally. Fish were taken only 

 north of 35°N. latitude during the fall but 

 were taken as far south as 29 N. latitude 

 during the winter. This shift in albacore 

 distribution appears to be related to a 

 similar latitudinal shift in the transition 

 zone, which is a zone of mixing between 

 two easterly flowing currents, the North 

 Pacific and the Aleutian. During the fall 

 the transition zone was considerable far- 

 ther north than during the winter. 



4. A study of the vertical stratification of 

 albacore indicated their presence throughout 

 the range of depths fished by the longline 

 gear. 



5. By means of chemical sounding tubes the 

 average maximum depth of the 5-fathom 

 floatline gear was found to be 405 feet on 

 Manning cruise 22 and 328 feet on Manning 

 cruise 23. The average maximum depth 



of the 1 5-fathom floatline gear was 432 feet 

 and 410 feet for the two cruises respectively. 



6. The albacore taken on the longline gear 

 ranged in size from 54 to 120 cm. (8 to 79 

 pounds), while all of the troll-caught alba- 

 core were smaller than 74 cm. (20 pounds). 

 The majority of the small albacore (less 

 than 80 cm.) were taken on the longline and 

 trolling gear during the fall survey, and 

 they were noticeably absent from both winter 

 surveys, indicating a movement of small 

 albacore from the area. 



7. None of the albacore taken on the longline 

 or trolling gear were in an advjinced stage 

 of sexual nnaturity. 



8. A total of 79 albacore, 54 bigeye, and I 

 yellowfin were tagged with the California- 

 type plastic vinylite tags. 



Bigeye tuna were regularly taken during all 

 three survey periods, usually south of the 

 area of albacore catches. The bigeye ranged 

 in size from 82 to 180 cm. (26 to 265 pounds). 



Damage to longline-caught fish by sharks 

 was negligible at 1. 1 percent even though 

 shark populations were apparently quite 

 large. Shark damage in equatorial waters 

 often reaches ais high as 20 percent. 



LITERATURE CITED 



BLUNT, C. E. JR. 



1954. Two mid-Pacific recoveries of 



California-tagged albacore. Calif. 

 Fish and Game 40(3):339. 



CLEMENS, HAROLD B. 



1955. Catch localities for Pacific albacore 



(Thunnus germo) landed in California, 

 1951 through 1953. California, Dept. 

 of Fish and Game, Fish Bull. 100:1-28. 



GANSSLE, DAVID, and H. B. CLEMENS 



1953. California-tagged albacore recovered 



off Japan. Calif. Fish and Game 

 39(4):443 



ISHIYAMA, REIZO, and K. OKADA 



1955. A new sting ray, Dasyatis atratus 

 (Dasyatidae, Pisces), from the 

 subtropical Pacific. Shimonoseki 

 College of Fisheries Journal 4(2): 

 211-216. 



MANN, HERBERT J. 



1955. Construction details of improved tuna 

 longline gear used by Pacific Oceanic 

 Fishery Investigations. U. S. Fish 

 and Wildlife Service, Comm. Fish. 

 Rev. 17(12):1-10. 



MURPHY, GARTH I., and T. OTSU 



1954. Analysis of catches of nine Japanese 



tuna longline expeditions to the west- 

 ern Pacific Ocean. U. S. Fish and 

 Wildlife Service, Spec. Sci. Rept. : 

 Fish. 128:1-46. 



, and R. S. SHOMURA 



1953a. Longline fishing for deep-swimming 

 tunas in the central Pacific, 1950- 

 51. U. S. Fish and Wildlife Service, 

 Spec. Sci. Rept. : Fish. 98:1-47. 



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