two vessels and the 2 years was 37.9 percent 

 of the entire period. On a seasonal basis, 

 "active"' time was 33 percent in winter, 45 

 percent in spring and fall, and 53 percent in 

 summer. These statistics suggest, as was ob- 

 vious from the logbook records, that repairs 

 and maintenance of the vessels usually were 

 performed during the winter and fishing effort 

 was intensified during the summer. 



The time spent traveling was nearly equiv- 

 alent to that spent day baiting. Of course, much 

 of the traveling usually is during darkness, for 

 the vessel departs for the fishing grounds in 

 the early morning hours and returns after dark. 

 The operational pattern for a fishery such as 

 the Hawaiian fishery, where the vessels have 

 short periods for taking bait and for fishing and 

 a limited carrying capacity for the catch, ob- 

 viously shows a higher percentage of time spent 

 traveling to baiting grounds, to fishing grounds, 

 and to port than would be true if longer inter- 

 vals could be spent fishing. 



AREAS OF PROFITABLE RESEARCH 



To make the skipjack tuna fishery more 

 productive through the modifications of the 

 methods of live-bait fishing, a number of ob- 

 vious problems would need solutions. Some 

 solutions would make the fishery more pro- 

 ductive immediately, but others would become 

 important later. 



A solution to the problem of the live-bait 

 supply would provide an immediate and major 

 increase in the production of skipjack tuna. 

 A means of quick access to live bait would 

 eliminate the daylight time spent taking bait. 

 A reduction in day-baiting time and traveling 

 time could increase production a minimum of 

 about 50 percent. Reduction in baitfish mortal- 

 ities during and after capture would add sub- 

 stantially to the usable supply of bait. The in- 

 crease in catch thus possible would be pro- 

 portional to the additional bait available for 

 fishing through reduction in mortalities and to 

 the reduction in traveling time to the bait 

 grounds. Although estimates place bait mor- 

 tality before use at about 25 percent, this level 

 is probably reached within 24 hours or less. 

 Bait catch data from Vessel A and Vessel B 

 suggest that mortalities approach 100 percent 

 within 5 days or less and that useful quantities 

 of baitfish seldom last beyond 2 or 3 days. It 

 is possible that improved bait-handling, which 



permitted longer survival for the nehu, would 

 increase skipjack tuna production by 50 percent 

 with fishing vessels of the types presently 

 used. Vessels designed to take advantage of 

 survival of baitfish over a longer period could 

 provide an even greater improvement in skip- 

 jack tuna production, since larger quantities of 

 bait could be taken to sea. A vessel with re- 

 frigeration could remain almost continuously 

 at sea fishing, returning to port only to dis- 

 charge the catch and renew its bait supply. A 

 successful fishing operation of this character 

 would also require a rapid procedure for ob- 

 taining live bait. A lengthy period of baitfish 

 survival at sea would permit the development 

 of vessels that could fish at greater distances 

 from port if distant tuna concentrations justi- 

 fied the longer trip. Such concentrations may 

 occur in the zone of enrichment along the 

 Equator. 



Mention has been made of the importance of 

 understanding the mechanism and releasers of 

 the feeding frenzy in tuna. What is it about a 

 baitfish species that makes one very effective 

 and another only moderately so? What are the 

 stimuli, and when and why are they most effec- 

 tive? Such information would be most useful in 

 selecting and testing various other species as a 

 possible baitfish for skipjack tuna fishing and 

 may actually lead to improved baiting and fish- 

 ing for the fleet. 



Another problem for which a solution would 

 be of value is where and when concentrations 

 of tuna occur. If their distribution is governed 

 by certain oceanographic characteristics or the 

 processes resulting therefrom, the ability to 

 predict oceanic conditions on the fishing ground 

 would be of great value. It has been estimated 

 that about one-tenth of the time spent scouting 

 and fishing is actually spent in the capture of 

 fish. A reduction in the scouting time, and use 

 of the time saved for fishing, could produce 

 major increases in production. To take full 

 advantage of the reduction in scouting time, an 

 increase in the supply of live bait would be 

 most desirable. A solution to the problem of 

 locating tuna, however, would give improved 

 catches without improvements in the baitfish 

 supply. Since a reduction in scouting time 

 would in effect have the same consequence as 

 an increase in the number of trips or vessels 

 fishing, and since live-bait fishing requires 

 baitfishes, the number of trips or size of the 

 present fishing fleet is, to a degree, keyed to 

 the available resource of baitfishes. We have 



