SKIPJACK IN HAWAII FISHERY 



289 



Figure 5. — Geographical distribution of catch and effort in the Hawaiian skipjack fishery, 1952 and 1953. 



whereas the trips by Honolulu-based fishermen to 

 the vicinit_y of Kauai are longer than a single day ; 

 therefore, tlie differences in tinie-of-trip between 

 the two areas are probably significant. 



Siniilarl}-, catch per unit of effort tends to in- 

 crease with increasing distance from shore ( fig. 7) . 

 Only a fraction of the total effort was expended 

 in the oceanic region as compared with the effort 

 inshore, and a few good catches of large fisli may 

 have produced an index far out of proportion to 

 the actual apparent abundance. Royce and Otsu 

 (1955, p. 18), however, report sighting more tuna 

 schools per day's scouting beyond 19 miles from 

 shore than were seen within 19 miles of shore. 



SIZE OF SKIPJACK AND POUNDS CAUGHT 

 PER UNIT OF EFFORT 



There is a positive correlation (fig. 8) between 

 the average size of skipjack caught in zones of the 

 fishery during the year (table (i) and correspond- 

 ing catch per unit of effort (table 5). Zones with 

 less than 5 percent of the total annual effort are 

 not included in the analysis because they ai'e un- 

 likely to represent fishing conditions througliout 

 the year. This correlat ion appears to substantiate 

 the observation that tlie larger skipjack usually 

 can be caught more efliciently than the smaller, up 

 to the size at which individuals must be gaft'ed in 

 landing and the efficiency drops. 



