from 46 to 96 minutes--in the average fishing 

 time per trip of the vessels. 



The catch from a skipjack tuna school is the 

 outcome of complex and interacting compo- 

 nents. For example, the fishermen can control 

 the number of men fishing and to some degree 

 have control over fishing duration, the amount 

 of bait used, and size of fish they will catch, 

 but have no control over the school's biting 

 behavior which adds to the complexity of pro- 

 ducing a catch. Furthermore, skill and ex- 

 perience of crewmembers are part of this 

 complex system, but these components are 

 difficult or impossible to quantify. 



In Hawaiian waters, the probability that a 

 vessel will catch one or more fish from a 

 school is roughly 50 percent. Royce and Otsu 

 (1955), who examined scouting data over a 

 period of 10 months, reported 43 percent suc- 

 cess, whereas Yuen (1959), who had data for 

 the fishing season from May to September, re- 

 ported 48 percent success among the schools 

 chummed. Collected at the peak of the fishing 

 season in June-August, our data showed that 

 the vessels chummed 1,036 schools (August 

 data for vessel F not included) and caught one 

 or more fish from 587 schools or 57 percent. 

 Individually, vessel A was most successful, 

 fishing 68 percent of the schools it chummed; 



vessel B was least successful, fishing only 48 

 percent. In the section that follows, we discuss 

 various components as they relate to fishing. 



Amount of bait used . --The amount of bait 

 caught or used in the fishery is measured in 

 units of a "bucket," which holds varying 

 amounts of bait, but usually about 3.6 kg. In 

 the beginning, we attempted to keep an accu- 

 rate, daily record of the quantity of bait in each 

 baitwell and the subsequent rate at which that 

 bait was used or died at sea, but found the pro- 

 cedure impractical on commercial fishing ves- 

 sels. We did, however, obtain data on amount 

 of bait used on each school, some of which re- 

 quired more than a bucket, others less. We 

 used one bucket as a minimum, even though on 

 some schools only a few handfuls or some 

 fraction of a bucket were used in chumming. 

 The amount of bait used, therefore, may be 

 overestimated, but we believe any error to be 

 reasonably small. 



We compared our estimate of bait used per 

 trip, which averaged 12.8 buckets (table 3), and 

 an earlier estimate made by Uchida (1967) and 

 found them similar. Uchida showed that in 

 1952-62, small vessels used 12.3 buckets and 

 large vessels used 15.4buckets of bait per trip, 

 whereas our data showed that, individually, the 



Table 7. — Number of schools with and without catches, and averages of catch per 

 school, number of men fishing per school, fishing duration per school, and 

 size of fish per school, tabulated by the amount of bait used per school by 

 seven Hawaiian skipjack tuna vessels, June-August 1967 



Bait used 

 per school 



Schools 



Catch 



per school 



Men 

 fishing 



Fishing 

 duration 



Fish 

 size 



With 

 catches 



Without 

 catches 



Bucket 



Number 



Number 



Number 



Metric ton 



Number 



Minute 



K£- 



1 



108 



383 



42. 







0. 



1 



6.1 



8 



6 



3.4 



2 



111 



18 



81. 



6 



0. 



4 



6.9 



15 



3 



5.4 



3 



99 



8 



110. 



8 



0. 



7 



6.8 



21 







6.6 



4 



75 



1 



158. 







1. 



1 



6.7 



25 



4 



6.7 



5 



76 



3 



164. 



6 



1. 



2 



6.8 



30 



3 



7.6 



6 



43 





203. 



6 



1. 



7 



6.8 



37 



5 



8.2 



7 



26 





205. 



8 



1. 



8 



7.5 



41 



1 



8.8 



8 



27 





187. 



4 



2. 







7.3 



44 



8 



10.9 



9 



8 





259. 



9 



3. 







7.4 



53 



6 



11.4 



10 



18 





251. 



9 



2. 



3 



6.9 



53 







9.2 



11 



4 





771. 



8 



1. 



8 



7.5 



93 



2 



2.3 



12 



8 





680. 



8 



3. 



3 



8.0 



66 



6 



4.9 



13 



6 





421. 



2 



4. 



4 



7.8 



69 



7 



10.4 



14 



2 





323. 







3. 



7 



8.0 



92 



.5 



11.5 



15 



4 





433. 



8 



5. 



2 



8.0 



72 







12.0 



>15 



7 





583. 



7 



5. 







7.8 



98.3 



8.5 



n 



