a long cruising range, and should be able to carry a large cargo nf fisli. 

 In other words, the venture will not show a profit unless the vessel can 

 carry over ^.0 tons of fuel, about /^0 tons of ice, and over 10,000 kan of fish. 



b. Fishing gear 



A comparison of cotton and ^fenila lines shows that the former is 

 superior both in the catch ratios obtained and in ease of handling. For 

 dyeing the line coal tar dye is best and line so dyed is easiest to handle. 



The experience of the third cruise indicates that in fishing for small 

 albacore of about 3 kan weight it would be best to remove the large hooks 

 from the lines and try to place as many small hooks as possible on them. 

 Since the more gear is fished at one time the greater are the catch ratios 

 obtained, it appears that about 200 baskets is a proper amount of line. 



c. Fishing methods 



Because of the great distance of sijch fishing grounds as those of Area 

 I it appears that of the three methods of pole fishing, longlining, and 

 trolling, pole fishing is unsuitable because of the bait factor. In the 

 long run it is thought that the best policy is to use longlines as the 

 principal gear and to use trolling lines while under way or vdiile patrolling 

 the lines to locate schools and to increase the total catch. There is a 

 need for a great deal of thought and study to be given to methods of opera- 

 tion of the gear. Attention must be paid to the movements of the schools 

 and to the direction and velocity of the current so that after the lines are 

 hauled in the position of the vessel can be suitably shifted, and when a 

 good fishing ground is reached it is necessary always to have i\n accurate 

 knowledge of the vessel's position after the lines are hauled so that 

 insofar as possible the vessel vixll not get off the ground. For this reason 

 ivhen operating at night it is absolutely necessary to ascertain the position 

 by observations of the moon or stars. 



d. Fishing grounds and seasons 



A consideration of the results of this year's and last year's investi- 

 gations leads to the belief that around Piay and June the grounds arc in the 

 vicinity of 30-35° N while around August and September they are in the 

 neighborhood of 4.0-45° N indicating perhaps thr-t the alLacoro may perform 

 a great migration between the Hawaiian Islands and the Aleutians in which 

 they move south in the winter and north in the summer. It is thought that 

 small albacore of about 2 to 3 kan in weight always svrim in schools at the 

 tips of warm currents (about 16-17° temperature) where these form narrow 

 pockets of comparatively uniform temperature. 



120 



