1. A study of bait returns shows a progressive decrease In the number of sardine 

 baits retrieved with increasing soaking time. 



2. With respect to sardine, there were no differences in catches as between salted 

 emd brined or between salted and fresh-thawed baits. 



3. Of the three principal bait species studied (sardine, herring, and squid), the 

 evidence shows the sardine to be the best longline bait. The sardine need only 

 be single hooked, whereas the herring in order to attain equal efficiency must 

 be double hooked. The sardine's superiority over squid is based on higher 

 catches in moderate to rough seas. If this advantage is due to visibility, 

 then the herring, which is similar in appearance to the sardine, should also 



be superior to the squid in rough seas, providing the herring are double hooked. 

 Thus the order of preferabillty of the conmionly available longline bait is 

 single-hooked sardines, double-hooked herring, and finally squid. 



4. The differences in the catch related to the kind of bait are not attributable 

 to dietary preference but are explained on the basis of availability or visi- 

 bility during the soaking period. 



5. It is unnecessary to make adjustments to the catches made by the different 

 species of bait and different baiting methods for POFI'a general study of tuna 

 abundance in the equatorial Pacific, because the differences in catch were 

 small in magnitude when contrasted with other sources of variability. 



LITERATURE CITED 



ANONYMOUS 



1952. Southern tuna fishery experiment report. Kanagawa Prefecture Fishery 

 Exp. Sta., No. 3, 35 pp. 



JUNE, FRED C. 



1950. Preliminary fisheries survey of the Hawaiian-Line Islands area. Part 

 I. The Hawaiian longline fishery. U. S. Fish and Wildlife Service, 

 Coram. Pish. Rev., vol. 12, No. 1, pp. 1-23, 18 figs. Also available 

 as U. ii. Fish and Wildlife Separate No. 244. 



KISHINOUYE, KAMAKICHI 



1917. The food of tunas. Sulsan Gakkal Ho 2(1):106-108. (Translation from 

 the Japanese by W. 0, Van Campen; duplicated as Pacific Oceanic Fishery 

 Investigations Translation No. 29.) 



MURPHY, GARTH I. and "KEITH C. ELLIOTT 



1954. Variability of longline catches of yellowfln tuna. U. S. Fish and 



Wildlife Service, Spec. Scl. Rept.: Fish. No. 119, March 1954, 30 pp. 



and T. OTSU 



1954. Analysis of the catches of nine Japanese tuna longline expeditions to 

 the western Pacific Ocean. U. S. Fish and Wildlife Service, Spec. Scl, 

 Rept.: Fish. No. 128, December 1954, 46 pp. 



__^_^ and R. S. SHOMURA 



1953a. Longline fishing for deep-swimming tunas in the central Pacific, 1950- 

 1951. U. S. Fish and Wildlife Service, Spec. Sci. Rept.: Fish. No. 98, 

 May 1953, 47 pp. 



1953b. Longline fishing for deep-swimming tunas in the central Pacific, 



January-June 1952. U. S. Fish and Wildlife Service, Spec. Scl. Rept.: 

 Fish. No. 108, August 1953, 32 pp. 



26 



