make a set without risking considerable damage to the netc However ^ 

 skipjack were present in the fishable area in fair quantitieSo 

 Nevertheless y the catch by the John Ro Mannin g was less than that 

 made by the Mak-oac, although the Makua fished off the Kona coast 

 exclusively and nade very poor catches (table 3)o 



DISCUSSION 



Before attanpting to draw any conclusions from the experiments 

 conductedj certain factors must be consideredo A more definite 

 knowledge of the migratory habits of the fish is necessaryo Although 

 it is a common belief among the commercial fishermen that the 3kip= 

 jack tend to migrate offshore as evening approaches and return to the 

 shoal areas in the morning^ no one has attempted to investigate what 

 paths the skipjack follow in this nocturnal migrationo The fisher- 

 men's observations are made only on the surface schools which they 

 happen to encounter at sunset during fishing operations o There is a 

 possibility that the najority of the skipjack sound and disperse or 

 migrate offshore through the deeper waters at nightfall and return 

 to the shoals along the same paths at daybreako Whether the skip- 

 jack school at night is also not definitely known^ but the few 

 skipjack caught during the experiment suggest that they do noto All 

 of them were taken singly or in pairs at rather wide intervals and 

 close to the surfaces 



There also is a possibility that the skipjack can see the net 

 and avoid itc Several observations made on the visibility of the net 

 in the water during daylight and at twilight showed that the untreated 

 nylon shackles and those treated with Dura Nett 200 were clearly visi- 

 bile down to ths lead lineo Those treated with Net life (green) and 

 the New Lodge Process (black) were less visible ^ the latter being the 

 least noticeable,, It is not certain whether the skipjack see the net 

 and avoid it, but a few incidents which occurred during the experiment 

 seem to suggest that they do« On two of the sets scattered flocks of 

 birds were seen milling aroiind and passing over the net^ hit the only 

 catch was one skipjack on one of the setSo If these bird flocks were 

 associated with schools of skipjack^ the poor catch possibly could 

 have been due to the skipjack's ability to see the net'o Night obser- 

 vations showed phosphorescence along the netj but it was not possible 

 to determine whether this affected the fishingo 



•While a sufficient number of schools were observed near Oahu and 

 Kauai to suggest the presence cf fairly large numbers of skipjack, 

 the observations were made during the day., and there is some basis 

 for believing that these fish were not available for capture at nighto 



18 



