An operational trial of 21 -hook gear (branch lines 7. 5 fathoms 

 apart) was conducted at 18 stations on Manning cruise 16. This 

 experiment consisted of appending 10 baskets of 21 -hook gear to the 

 longest fishing end of sets of mixed 6- and 11-hook gear. The results 

 at two stations were complicated by the presence of land, and on four 

 stations no yellowfin were taken. On the remaining 12 stations the 21- 

 hook gear caught 71 yellowfin, the nearest 8 baskets of 11-hook gear 

 caught 21 yellowfin, and the nearest 12 baskets of 6-hook gear took 53 

 yellowfin. The respective catches per basket were 0.68 for 21-hook, 

 0.22 for 11-hook, and 0.37 for 6-hook. These data suggest that the 

 catch per basket can be increased over that given by the 11-hook gear, 

 but it is also evident that sampling was inadequate and that fishing time 

 was not equal, for the 21-hook gear was in the water longest. 



Spacing the hooks closer together, at intervals of about 15 

 fathoms, appears to be advantageous to commercial fishermen. The 

 additional cost of adding 5 droppers to the normal 6-hook gear is so 

 small that a decision would appear to hinge on the speed of hauling. 

 Experimental data are not available, but the increase in hauling time 

 due to extra hooks can be inferred from time studies on the 11-hook 

 gear. 



In the absence of tangles one basket of 11-hook gear is hauled in 



about 3 00 . On the average about 3 seconds is required to remove 



a dropper (time from stop to start of the hauler). Extrapolating we 



estimate that 6-hook gear with wire links would have been hauled in 



m s & 



2 45 . The 11-hook gear then takes 1.09 times as long to haul, and 



our information to date indicates that it catches 1.21 times as many 



yellowfin. 



Another factor to be considered, however, is the tendency for 

 more branch lines to break or be lost when using the 11-hook gear with 

 the wire sections. For instance 559 baskets of 6-hook gear (3, 354 

 branch lines) suffered 25 broken branch lines. At the same time 559 

 baskets of 11-hook gear (6, 149 branch lines) suffered 66 broken branch 

 lines. The percent of failure is 0. 75 in the 6-hook gear and 1.01 in 

 11-hook gear, indicating that design changes that reduce branch line 

 failures will further increase the catch of 11-hook gear relative to 

 that of the 6-hook gear. 



In summary, it appears that the Japanese -type gear on which 

 POFI based its 6-hook baskets has been substantially improved by 

 innovations in construction and by spacing hooks closer together. 



24 



