after 1953 (fig. 5). The percentage of effective 

 inshore trips did not differ greatly between 

 Class 1 and Class 2 vessels. For Class 1 vessels, 



1950 1951 1952 1953 1954 1955 1956 1957 1958 1959 1960 

 YEAR 



Figure 4. — Annual averagres of number of men hook- 

 ing per effective trip on Class 1 and Class 2 Hawaiian 

 skipjack tuna vessels, 1950-60. 



DISTRIBUTION OF EFFORT BY AREA 



About 80 percent of the effective trips during 

 any given year were in the inshore area (table 

 7). The percentage of effective inshore trips 

 for both classes of vessels declined from 1952 

 to 1953. Class 1 vessels showed a further 

 decline in 1954, then a gradual increase, where- 

 as Class 2 vessels showed a gradual increase 



Table 7. — The number and (in parentheses) percentage of 

 effective trips by Class 1 and (lass 2 Hawaiian skipjack 

 tuna vessels in inshore and offshore areas, 1952-62 



' Percentages were computed from the average annual numbers of effective 

 trips. 



1952 1953 1954 1955 1956 1957 19SB 1959 I960 1961 1962 

 VKAH 



Figure 5. — Percentage of effective trips inshore by 

 Class 1 and Class 2 Hawaiian skipjack tuna vessels, 

 1952-62. 



the percentage of inshore trips, on the average, 

 was 81 percent, whereas for Class 2 vessels, 

 the average was 83 percent over the 11 years. 



A summary of effective trips by areas for 

 each size class of vessels with respect to poor 

 years and average and good years showed that 

 in poor years, the percentage of effective in- 

 shore trips by Class 1 vessels was 84 percent ; 

 in average and good years, it was 81 percent. 

 For Class 2 vessels, the values were 86 percent 

 in poor years and 82 percent in average and 

 good years. 



One may wonder if skipjack tuna are more 

 abundant inshore, since a larger percentage of 

 the total trips is made within 20 miles from 

 land. Observations of skipjack .schools in Ha- 

 waiian waters in 1953 indicated that sightings 

 of tuna schools were equally numerous offshore 

 and inshore except for .sectors to the northeast 

 and southwest of Oahu (Royce and Otsu, 1955). 



If schools are equally abundant offshore and 

 inshore, the question arises as to why effort 



188 



SKIPJACK IN HAWAIIAN WATERS 



