the analysis of various mechanical and semimechanical factors that 

 might affect the efficiency of the gear» The data relative to this 

 problem will be presented in a separate report. With one exception 

 there do not appear to be any factors, other than sampling varia- 

 tion and abundance (or availability), that seriously affect the 

 size of the catches, and therefore the use of the catches as an 

 index of abundance. This exception will be mentioned in an appro- 

 priate place in the text. 



Throughout the body of the report the vernacular names 

 of fishes are used. These, with their usually accepted scientific 

 names, are as follows s 



Marlin - Makaira spo 



Sailfish - Istiophorus orientalis (Schlegel) 



Wahoo - Acant ho cyb i um solandri (Cuvier and 



Valenciennes) 

 Dolphin - Coryphaena hippurus Linnaeus 

 Yellowf in tuna - Neothunnus macropterus (Temminck and 



Schlegel) 

 Bigeye tuna - Parathunnus sibi (Temminck and Schlegel) 

 Skipjack = Katsuwonus pelamis (Linnaeus) 

 Albacore - Germo alalung a (Bonnaterre) 

 Lancet fish - Alepisaurus sp. 

 Barracuda - Sphyraena barracuda (Walbaiun) 



ACKNCWLEDGBMENTS 



Many workers were responsible for the planning and execution 

 of the field work, Fred Cleaver was formerly responsible for the 

 organization and planning of this experimental fishing project, and 

 considerable credit for the knowledge gained is due to his careful 

 planning of cruises 5 and 7„ Joseph King was field peirty chief on 

 Smith Cruise 5, Fred Cleaver on Smith Cruise 7, and Townsend Cromwell 

 on Smith Cruise 11, 0, E, Sette, M„ B, Schaefer, and J, L„ Kask 

 contributed greatly to the success of the cruises through advice and 

 direction. Finally, the successful completion of the cruises was 

 due in large measure to the enthusiastic performance of the officers 

 and fishermen of the Hugh Mo Smith, 



DESCRIPTION OF LONGLINE FISHING 



Longline fishing catches deep-swimming tuna, and these 

 appear to represent a different segment of the population from those 

 found at the surface and taken by trolling and live-bait fishing. 

 This is shown graphically in figure 2o That the size difference is 

 not due to gear selection is indicated by data given in a later 

 section. 



Shapiro (l950) gives an excellent account of the historical 

 development of commercial longline gear in Japan, Several authors 

 (Shapiro 1950, June 1950, and Shimada 1951) have given complete 



