Fishing Methods , During the early phases of our investigations 

 we tested practically all conventional methods of fishing for tuna. 



Trolling has been regularly done by POFI research 

 vessels when underway to and from the Equator and on daylight 

 runs between stations on hydrographic and fishing trips. Diring 

 5,525 line-hours of such incidental irolli-g oiily 13 tuna were 

 caught; 8 were yellowfin and 7 were skipjack. In contrast, delib- 

 erate trolling close to island reefs when the vessel is maneuvered 

 through schools at reduced speed has produced a much larger 

 catch. In the Line and Phoenix islands we have deliberately trolled 

 for tuna a total of '^-69 line-hours catching 280 tuna or 29.0 per 

 100 line-hours. These v/ere praccically all yellowfin luna andrnost 

 were of sizes betvveen 16 and 60 pounds. Assu-ning a commercial 

 vessel were fishing six lines, ihis would rr.ean a catch of a/.out 17 

 tuna or about 600 pounds per 10-hoo.r day. 



Purse seining was cried in the Phoenix Islands on two 

 occasions, one during the summer of 19-0 and the second trial 

 during Januaryand February 1951. During both of these attempts 

 a number of tuna schools were sighted but rough seas and strong 

 winds hampered the operations and no tuna were caught. Five 

 tiips were male to the Line Islands during 1950-K51. Although 

 75 schools of tuna ware observed, most of them were toe wild or 

 too close to the reefs for setting the seine. Of the eight schools 

 that it was possible to set on, fish were still in the circle of net 

 when pursing began in six instances out they sounded out before 

 the net was closed. On the other two sets the fishprobably escaped 

 before pursing began. Further purse seine trials were attennpted 

 around the Hawaiian Islands during 195 1. Several schools or parts 

 of schools were captured by engaging a sa..'-.-. .an to chuna the fish 

 while the purse seine v/as set around the school. Without such 

 chumming the fish escaped from all sets that were cried. It ap- 

 pears that in the central Pacific purse seining is not a practical 

 means of capturing tuna in conimercial quantities. 



Surface gill nets were used in the vicinity of the 

 Hawaiian Islands for a total of 2J4 hovirs daring the summer of 

 1951. A report has been pullished on the results of these trials, 

 most of which were carried on during the night. Fishing was con- 

 fined to the lee of the larger islai.ds ecause of the tJifficulty in 

 handling the gear in rough v/'aters. Soaie of the trials were in 

 areas known to '6 productive of skipjack and during their season 

 of abundance. A total of 28 fish were taken by the gill nets of 

 which only 7 were tuna. It was concluded that surface gill netting 

 also shows very little proiTiise as a commercial fishing method for 

 skipjack in central Pacific waters. 



31 



