is a general belief among the Hawaiian skipjack 

 tuna fishermen that more bird flocks are 

 sighted early in the morning and late in the 

 afternoon. In contrast, another research cruise 

 in June 1953 encountered a peak in sightings at 

 1100-1200 with a fairly large number of bird 

 flocks sighted at all hours between 0700" and 

 1700. The lack of consistency among cruises 

 also suggests that the dips and peaks in sight- 

 ings result from changes in bird or fish 

 behavior. 



The spatial distribution of catches was simi- 

 lar to that of sightings (fig. 12). The percent- 

 age of schools with catches relative to sightings 

 varied widely among the individual 20-minute 

 areas of longitude and latitude, but the percent- 

 ages calculated for larger sector s--east, west, 

 north, and south of Oahu — varied little. It 

 should be mentioned that the observers did not 

 record the positions of some of the schools 

 sighted, particularly those schools they encoun- 

 tered during their first week or two of sea duty. 

 The reasons they gave were that they were 

 seasick, were too far offshore, or were expe- 

 riencing poor weather conditions which inter- 



fered with making a reasonably accurate esti- 

 mate of the sohoors position. The recording of 

 school positions improved as the observers 

 became accustomed to sea life and learned to 

 work closely with the captain and the fishermen. 



In our calculations, we used only schools 

 with positions recorded; therefore, the per- 

 centages are overestimates and are of value 

 only in comparing one sector with another. 

 Data presented in figure 5 showed that collec- 

 tively, the percentage of schools with catches 

 relative to sightings was only 47 percent, but 

 by using only those schools with positions, we 

 calculated that 60 percent of the schools sighted 

 yielded catches. In sectors to the south and 

 east of Oahu, the vessels caught fish from 62 

 and 61 percent, respectively, of the schools 

 sighted, whereas in sectors to the west and 

 north, they caught fish from 58 and 55 percent 

 of the schools, respectively. Catch per school 

 data from all four sectors ranged from 0.8 

 metric ton in the north to 1.2 metric tons per 

 school in the west with intermediate values of 

 1.0 metric ton in the south and 1.1 metric tons 

 in the east. 



Table 14. — Number and percentage of trips tabulated by time meals were eaten 

 aboard the seven Hawaiian skipjack tuna vessels, June-August 1967 



Time 



Breakfast 



Lunch 



Dinner 



Number 



Percent 



Number 



Percent 



Number 



Percent 



0001-0100 















0101-0200 















0201-0300 















0301-0400 















0401-0500 



9 



6.9 











0501-0600 



103 



79.2 











0601-0700 



18 



13.9 











0701-0800 















0801-0900 















0901-1000 







15 



8.7 







1001-1100 







83 



48.0 







1101-1200 







42 



24.3 







1201-1300 







21 



12.1 







1301-1400 







9 



5.2 







1401-1500 







3 



1.7 







1501-1600 











1 



0.9 



1601-1700 











8 



7.6 



1701-1800 











33 



31.1 



1801-1900 











46 



43.4 



1901-2000 











16 



15.1 



2001-2100 











2 



1.9 



2101-2200 















2201-2300 















2301-2400 















Totals 



130 





173 





106 





19 



