In Japan, major fisheries for skipjack tuna and albacore 

 depend on the pole-and-line method. The boats have a long, 

 high bowsprit, Yoshida says, and carry fishing racks along 

 one or both sides, around the stern, and along the bowsprit. 

 As a group, they are smaller than the longline vessels ; the 

 largest is no more than 180 gross tons. The skippers locate 

 fish schools by various means. Lookouts watch for bird 

 flocks, floating timbers, and other indicators of the likely 

 presence of fish. Most vessels have a full-time radio operator 

 whose principal duty it is to obtain and relay reports on how- 

 fishing is going. 



When a school is sighted, live bait is thrown overboard to 

 concentrate the school near the vessels. On the fishing racks, 

 the young, skilled fishermen are stationed along the bowsprit 

 where the lift is highest (and the work hardest) and the 

 older or less skilled fishermen around the stern and sides. 

 The Japanese obtain their bait by purchasing it from 

 dealers. At the peak of the season they are supplied on 

 the fishing grounds by special bait-carrying craft. 



The Japanese mode of pole-and-line fishing was introduced 

 into Hawaii around 1900. It has been somewhat modified to 

 suit local conditions. A distinct type of vessel has evolved, 

 at 50 to 80 feet long much smaller than the Japanese ships 

 and lacking the distinctive fishing racks of the Japanese 

 vessels. Most fishing is done from the stern (fig. 26). The 

 crew is smaller. The vessel moves ahead at low speed while 

 fishing, whereas the Japanese vessels lie "dead" in the water. 

 Another difference between the Japanese and Hawaiian tech- 

 niques appears in the method of obtaining bait. In Hawaii, 

 each vessel seines for its own bait, usually the nehu. Some 

 spend almost two-thirds as much time fishing for bait as 

 fishing for tuna. 



For several decades, surface schools of skipjack and 

 yellowfin tunas near the shores of the Americas in the 

 eastern Pacific were fished by pole-and-line vessels. The 

 schools there are relatively compact, with many individuals 



in each. They are thus susceptible to purse seining. Begin- 

 ning in the late 1950's, many of the famous tuna clippers 

 of the California coast were converted to, or replaced by, 

 modern purse seiners. Technological innovations — notably 

 the development of nets of light, tough synthetic fibers and 

 of mechanical devices for power handling of the seines — 

 triggered the conversions. In purse seining, a great net, 

 about half a mile long and 300 feet deep, is set in a circle to 

 entrap a school of tunas. As the net is drawn to the ship, 

 the fish are confined to a smaller and increasingly smaller 

 portion of the net, until the .squirming mass of living treas- 

 ure can be hauled aboard. Both purse seiners and tuna 

 clippers depend on visual methods to locate fish. The Califor- 

 nians have one refinement: They often use small aircraft to 

 do some of their spotting for them and report the location 

 of schools by radio. 



The principal tuna catches of the Pacific are made by 

 these methods. The small catch of albacore off the U. S. 

 coast is taken as well by still another technique. Small ves- 

 sels are fitted with as many as 11 troll lines, which fish the 

 near-surface waters behind the ship. One of these troll lines, 

 by the way, is called the "whiskey line," for by tradition the 

 fish it catches are sold to buy liquor for the crew. 



Scientists say that the specialized vessels and techniques 

 now in use may have to be radically changed if the full 

 potential of the central Pacific tuna resources is realized. 

 It seems undeniable that the subsurface behavior of the 

 tunas themselves will help write the specifications the new 

 craft and new gear must meet. How the fish behave when 

 they are away from the surface is now being studied at the 

 Laboratory in Honolulu by the use of a CTFM (continuous- 

 transmission, frequency-modulated) sonar to study the dis- 

 tribution and behavior of fish schools at sea (fig. 27). The 

 sonar (the word is an acronym for "sound navigating and 

 ranging") was installed on the research vessel Toivnsend 

 CromiccU in 1966. Scientists have now obtained information 



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