Some Operational Aspects of the Hawaiian 



Live-Bait Fishery for Skipjack Tuna 



( Katsuwonus pelamis ) 



By 



VERNON E. BROCK, Director 



Hawaii Institute of Marine Biology and Professor of Oceanography 

 University of Hawaii, Honolulu, Hawaii 96822 



and 



RICHARD N. UCHIDA, Fishery Biologist 



Bureau of Commercial Fisheries Biological Laboratory 

 Honolulu, Hawaii 96812 



ABSTRACTS 



An analysis of detailed operating records of two Hawaiian skipjack tuna 

 vessels during 1952 and 1953 indicated consistent patterns of time utilization 

 and activities that probably were representative for the Hawaiian skipjack tuna 

 fleet during these 2 years. Availability of skipjack tuna appears to be lowest 

 during the winter; hence, the vessels are drydocked and repaired then. The 

 pattern of fishing was marked by a period of bait collection lasting a day or 

 more, followed by a period of fishing that lasted from 1 to 5 days, but generally 

 was 3 days or less. Baitfish mortality rates were so high that it was difficult 

 to maintain a large quantity of live bait, or to fish successfully for more than 

 3 days. The design of the skipjack tuna vessels and their operating procedure 

 reflected these constraints in the use of bait. Long-range vessels with refrig- 

 eration, possibly able to fish more efficiently during the winter, would be im- 

 practical without the development of methods to reduce baitfish mortalities. A 

 fishery for live bait, independent of the tuna fishing vessels, would require the 

 same techniques to be successful. 



Much of the time at sea was spent in searching for fish rather than in 

 fishing. A reduction in time spent searching would reduce the loss of baitfishes 

 in the baitwells and increase the catch of skipjack tuna for baitfish used. Hence, 

 knowledge of areas where skipjack tuna are concentrated would be of substantial 

 value to the fishery. 



INTRODUCTION year (Rothschild, 1966; Silllman, 1966). Hawaii. 



which now has a modest fishery for this spe- 

 The skipjack tuna ( Katsuwonus pelamis ), cies, may well become the optimum base for 

 which appears to be the major underutilized an expanded fishery. The present study ex- 

 fishery resource of the central Pacific, has amines the Hawaiian skipjack tuna fishery and 

 been estimated to offer minimum potential some of the limitations whose removal, wholly 

 yields of 140,000 to 225,000 metric tons per or in part, could lead to the development of a 



