FISHERY BULLETIN: VOL. 73, NO. 4 



The relation between the annual total landings 

 of albacore and the total fishing effort (number of 

 fishing trips) indicated that the annual landings 

 increased with increasing fishing effort from 1954 

 to 1965. Based on this analysis, Otsu and Sumida 

 (1968) concluded that the point of maximum yield 

 of albacore had not been reached in the American 

 Samoa-based fishery. The fishing effort continued 

 to increase subsequent to 1965, and reached a peak 

 of close to 800 fishing trips in 1967. The albacore 

 landings also continued to increase with the 

 increased effort. The relation between the annual 

 landings and the effort, in total number of days 

 fished, from 1959 to 1967 also showed that the 

 landings increased with increasing fishing effort 

 (Figure 3). The mean catch per day plotted against 

 effort in total number of days fished, however, 

 shows a decline in the CPUE from 1959 to 1971 

 with increasing effort (Figure 4). 



As noted earlier, our laboratory has been ob- 

 taining, from the vessel operators, effort data in 

 terms of number of hooks fished since 1963. Using 

 these data, the mean monthly catch per 100 hooks 

 of albacore from 1963 to 1971 was computed 

 (Figure 5). A salient feature of Figure 5 is that the 

 mean monthly CPUE fluctuated much more from 

 1966 to 1971 than they did from 1963 to 1965. It is 

 not clear what caused this change in trends in the 

 monthly CPUE after 1965. One possibility is that 

 it is related to a geographical change in fishing 

 effort. As will be discussed in more detail in 

 another section, in the years after 1965 more 

 fishing effort has been expended in latitudes 

 south of lat.20°S where good CPUE's of albacore 

 are obtained in the second and third quarters of 

 the year. This fact could also account for the 

 definite peak in abundance of albacore in June or 

 July during 1966 to 1971. It is also evident, 

 however, that there is a slightly declining trend in 

 the CPUE from 1963 to 1971. 



A plot of the total annual catch of albacore 

 against the estimated total annual effort in 

 number of hooks fished from 1963 to 1971 is shown 

 in Figure 6. During this period the estimated total 

 effort ranged from about 13,165,000 to 51,092,000 

 hooks and the annual albacore catch from 10,652 to 

 28,310 metric tons. With some minor exceptions, 

 there was a strong positive relation between the 

 annual catch and effort for the 1963-71 period. 

 Generally, the catches increased with increased 

 fishiijg effort. Suda (1971) also found a similar 

 relationship between albacore catch and fishing 

 effort in the South Pacific from 1952 to 1968. 



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18 20 22 24 26 28 30 32 



EFFORT ( THOUSANDS OF DAYS FISHED ) 



Figure 3.— Relation between annual landings of albacore and 



effort. 



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2 4 6 e 10 12 14 16 18 20 22 24 26 28 30 32 34 

 EFFORT (THOUSANDS OF DAYS FISHED) 



Figure 4.— Relation between mean catch of albacore per day and 



effort. 



In Figure 7 is plotted the CPUE in number of 

 fish and in weight per 100 hooks fished against the 

 estimated total annual number of hooks fished 

 from 1963 to 1971. Both plots show a negative 

 relation between CPUE and effort; the CPUE 

 decreased with increased fishing effort. Thus, 

 although the catch has been increasing with 

 increasing effort, it appears that the fishery has 

 had some effect on the stock size in that the CPUE 

 has been declining with increasing effort. 



The analyses above reflect average conditions of 



750 



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