TROLLING JIG 



A Hen or eagle feathers 



B Ventral skin of file fish 



C Lead or bone 



D Shell 



MOTION (HO SOAP 



Tlgura 18 



region. Until the adrent of englned ^>oate, lone lin« operations were confined to waters not 

 too distant fron the coast. The main species obtained hjr these operations was the hlaclc tuna. 

 Tel3owfln tuna and other species were taken Incidentally. Vfhen It hecame possible to exploit 

 the offshore pelagic grounds the tuna long line assumed a position of major Importance as a 

 fishing technique. Blaok, yellowfln, and blg-eyed tunas, albacore. marline, and sharks pro- 

 vide the bulk of the catch obtained by this method. Qcoaslonally swordflsh and sallflsh 

 swlmnlng at deep lerels are also taken. 



The structure of the gear (Figure 19. Table 7) and the depth at whloh the hooks are 

 placed differ by SDeclos, oceanographlc factors, locality, season, and preference of the In- 

 dividual fisherman. O-enerally. for the same species the hooks are placed In deeper water In 

 the more southern latitudes and at higher levels la colder waters. The length of the float 

 line can be changed to permit such adjustments. Long lines constructed primarily for black 

 and yellowfln tunas are suspended to depths of 75 meters or more, and the hooks number from 

 2 to 10 per set (the distance between two flag buoys). Long lines designed mainly for alba- 

 core have the hooks placed at a depth between 30 to 60 meters, and the hooks number from 10 to 

 30 per set. The same long line may be operated for all species. If so, branch lines of var- 

 ious lengths are used on one set. 



The material most often used for the main, float, and branch lines is cotton, which 

 may range In diameter from 2.5 mllliiiiaters for albacore to 6 mllllmptere for large tuna. 

 Nanking hemp or a mixture of henp and cotton, about 8 millimeters in diameter. Is sometlnes 

 used. For the "sekiyama" (Figure 19) cotton wound around a core of hemp Is preferred, but 

 wire Is sometimes used as the core. In albacore lines the sekiyama and wire leader may be 

 omitted and the hook attached directly to the branch line. Swivels are often placed at some 

 point along the branch line to minimize tan^jllng of lines. 



m 



f-6307 



