and with wind speed5./. The three comparisons 

 yielded low, non-significant correlation values 

 suggesting that these effects individually were 

 not related to the skewness observed in the 

 baskets (r = 0. 039, r = -0. 055 , and r = 0. 055 

 respectively). 



On the other hand, certain events in 

 retrieving the gear, which could not be evaluated 

 statistically, appeared closely associated with 

 skewness of the baskets. Figure 5 shows three 

 general directions at which longline gear was 

 hauled aboard the POFI vessels: (1) Off the 

 bow with the vessel's speed equalling the speed 



Figure 5. --Three general positions at which 

 longline gear is retrieved: (I) Off the bow; 

 (2) abeam; and (3) astern. 



— Wind direction was ignored. It i s a 

 general practice on POFI vessels to set longline 

 gear downwind and the vessel captains were 

 reasonably successful in doing so. Of 98 sets 

 made, 80 percent were with, to abeam of the 

 wind and only ZO percent against, to abeam of 

 the wind. 



at which the line is brought in; (2) off midships 

 with the speed of retrieving somewhat slower 

 than that of the vessel; and (3) with the line 

 astern and coming in much slower than the 

 speed of the vessel. Differences in position 

 between nunnber I and 2 probably do not have 

 any important effects on sounding tube measure- 

 ments since the line is retrieved while at or 

 above the maximum fishing depth. But, between 

 2 and 3, we believe that the vessel actually 

 closes up the buoys of a basket and allows the 

 mainline to sink. Since part of the line would be 

 under tension from the line hauler only a portion 

 would sink; which portion would depend on many 

 conditions such as the speed of the line hauler, 

 the distance between the "lay" of the longline 

 and the parallel course of the vessel, etc. 



In addition to the effects on the line by the 

 normal hauling procedure, disrupted retrieving 

 could be responsible for obtaining sounding tube 

 readings exceeding the depth at which the 

 longline actually fished. On some longline 

 stations, sounding tubes were attached on hook 

 7 position (hooks were omitted) at intervals 

 along the set. In a few cases a sufficient num- 

 ber of tubes were attached to allow an exami- 

 nation of the "lay" of the entire nnainline. 

 Figure 6 shows the unadjusted depth distribution 

 of hook 7 on baskets of four longline stations. 

 Each station or set was made up of 40 baskets 

 of longline with one bookless basket (unnumbered 

 in fig. 6) inserted between baskets 25 and 26. 

 Stations 17 and 18 of the Manning cruise 25 

 were occupied on consecutive days, as were 

 stations 32 and 33 of the Gilbert cruise 27. 



JRM 25 



- "STATION 171 



« STATION 18/ 



o STATION 32lr„r 97 



. STATION 33;'^"'^ ^^ 



• a> HOOK 7 PREDICTED FROM 

 OBSERVED VALUE OF HOOK 6 



20 



25 20 



BASKETS 



Figure 6. --Depth distribution of hook 7 on 

 baskets of longline at stations 17 (31*36'N. , 

 165°16'W.) and 18 (33'40'N. , 165'32'W.) of 

 the John R, Manning cruise 25, and 32 

 (34'3rN. . 162''50'W. ) and 33 (32'16'N., 

 163*04'W.)of the Charles H. Gilbert cruise 27. 



