T 



I i I I I I I I I I I I I 

 1.0 2.0 3.0 4.0 5.0 6.0 7.0 8.0 9.0 10.0 1 1.0 \Z0 13.0 



CATCH PER TRIP (METRIC TONS) 



Figure 14. — Relation between catch per trip and 

 average number of schools fished and average 

 catch per school by seven Hawaiian skipjack tuna 

 fishing vessels, June-August 1967. 



From data on unloading catch and loading 

 ice, we found that the weight of fish unloaded 

 varied among the vessels from an average of 

 2.4 to 4.1 metric tons and collectively averaged 

 3,4 metric tons. In table 3, we noted that catch 

 per trip was 2.8 metric tons, a figure some- 

 what lower than the average of 3.4 metric tons 

 unloaded at the docks. The discrepancy be- 

 tween the catch per trip and the average catch 

 unloaded occurs because catch per trip was 

 based on a single day's fishing, whereas the 

 unloaded catch included, in some cases, the 

 catches of 2 or more days of fishing. 



Usually about 9 men, including crewmembers 

 and shoreside helpers, unloaded the vessel, with 

 a range of 7 to 13 men. Unloading usually re- 

 quired about one-half hour; the average unload- 

 ing time among the vessels ranged from 26.8 to 

 33.0 minutes. 



The rate of unloading depended largely on the 

 size of the fish. Vessels which caught small 



fish usually had low unloading rates. On the 

 contrary, vessel B, which had the highest un- 

 loading rate per man-minute at 16.8 kg., caught 

 fish which averaged 9.5 kg., the largest average 

 among the vessels. 



In loading ice, the vessels averaged from 3.7 

 to 11.4 minutes with a grand mean of 6.6 min- 

 utes. Since loading ice is at a fixed rate, the 

 loading time varied directly with the quantity 

 loaded. 



OPTIMUM VESSEL OPERATION 



There appears to be a certain pattern to a 

 successful operation in the fishery for skipjack 

 tuna in Hawaiian waters. Using catch, which is 

 convertible into earnings as a measure of suc- 

 cess, we found that certain characteristics dif- 

 fer between a high- and low-producing vessel. 



There were several aspects of the operations 

 of vessel F, a low producer, which contrasted 

 sharply with those of vessel A, a high producer. 

 Both were below average in pursuit time, but 

 vessel A pursued its schools almost twice as 

 long as vessel F. Vessel A chummed its 

 schools slightly longer than average; vessel F 

 only about half as long as the average of all 

 vessels. In fishing, vessel A, which averaged 

 slightly longer than vessel F in fishing per trip 

 and per school, had values higher than the 

 seven-vessel averages in these categories. In 

 number of men hooking per school, vessel F 

 had six men, which is not dissimilar from the 

 seven-vessel average, but vessel A usually had 

 seven men fishing. 



Moreover, vessel A used unusually large 

 amounts of bait at sea, averaging about 23 

 buckets per trip, whereas vessel F used only 

 about 9 buckets, which is 25 percent less than 

 the average for the seven vessels. A similar 

 difference between these vessels can be seen 

 in the average amount of bait used per school. 

 Vessel A succeeded in fishing 64 percent of the 

 schools it sighted, whereas vessel F succeeded 

 in fishing only 56 percent of its schools. 



More time spent pursuing and chumming the 

 schools, more men available for fishing, and 

 more bait used per school undoubtedly contrib- 

 uted to a larger catch per school for vessel A. 

 Averaging 1.3 metric tons per school, vessel A 

 usually caught nearly twice as much per school 

 as vessel F, which averaged only 0.7 metric 

 ton. 



Data on catch per bucket of bait used in fish- 

 ing, however, cast doubt that the operation of 



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