Table 3, --Summary of the tuna catch. Manning cruise 12. (This 

 tabulation includea only the catches at stations where 

 40 standard baskets (240 hooks) were fished in a manner 

 designed to furnish an index of abundance. Other stations 

 and experimental gear are considered elsewhere. More 

 complete data will be found in the appendix. ) 



The section along 169 W, longitude in November 1952 (fig, 7, table 4) shows some- 

 what less evidence of upwelling in the vicinity of the Equator than do the sections to the east. Co- 

 incident with this, there was little indication of a yellowfin concentration to the north of the Equa- 

 tor. In general, the fish seenn to have been more evenly spread over the entire section, with 

 only a slight tendency to aggregate in the vicinity of the Equator, 



In sxunmary, the distribution of yellowfin tuna along the Equator in the central Paci- 

 fic as revealed by the results of these four cruises is consistent with the distributions obtained 

 during 1950 and 1951 in the late summer and fall. There is evidence, however, that the abundance 

 was somewhat less during the early fall of 1952 than during the same period of 1951, During the 

 earlier period a series of 10 stations over a rather wide area west of 150 W, longitude at approxi- 

 mately 2 N, latitude produced catches of yellowfin averaging over 12 fish per hundred hooks. 

 During the fall of 1952 a larger number of stations in the same general locality resulted in only 

 two catches near 12 per hundred hooks, and the average was about 6 yellowfin per hundred hooks. 

 As yet there is no adequate explanation for this variation in the level of abundance. 



The cruises undertaken in the equatorial region provide only limited infornnation on 

 the distribution of albacore. This species is so important to the American tuna industry, however, 

 that there is some justification for a preliminary statement of our findings. In general our surveys 

 indicate that albacore are more abundant south than north of the Equator, This is shown by catches 

 made along 169 W. longitude at about 5 S. in November 1952 (table 4), and by the good catches 

 made at 5 -8 S. latitude along 169 W, and 180°W. longitude in February 1952 (Murphy and Sho- 

 mura 1953b), Albacore appear to be more abundant to the west, as evidenced by the almost nega- 

 tive results along 120 W, and 130°W, (table 1), moderate results along 140 W, and 150 W, 

 (tables 2 and 3), and relatively high catches along 169 W, and 180 W, (table 4 and Murphy and 

 Shomura 1953b), The best catch was made during February 1952, when 6 albacore per 100 hooks 



11 



