It need hardly be said that the most effective way to bring 

 operating efficiency to its highest level is to select for opera- 

 tions the areas in which the tuna are present in the greatest con 

 centrations. This, in other words p means the selection of good 

 fishing groundso This is the field which has received the most 

 attention hitherto^, and it is hardly an exaggeration to say that 

 fishery investigations and fishing ground surveys have almost been 

 limited to this one objectiveo 



However J, the problem under discussion here is not that of the 

 methods to be followed in selecting a fishing ground^ but that of 

 the construction of the most efficient gear for a given groundo 

 This sort of problem, in spite of its importance^ generally receives 

 little attention in comparison with the interest shown in the matter 

 of scouting for fishing groundso There is almost no scientific 

 basis worth mentioning for the consideration of such problems as 

 the length of branch lines and float lines, that iSj, the depth at 

 which the hooks should fish, the number of branch lines j and so 

 forth. The construction of the lines is determined simply by 

 experience, or by imitation of others, or according to the materials 

 available o 



It hardly need be said that errors in the selection of fishing 

 grounds can have a lethal effect on the fishery^ but even though 

 there are no such errors^ if the fishing gear is unsuitable, the 

 results of the fishing will naturally be inferior,, As an example, 

 the results obtained by the HakuyF Maru^-'-'^'' on training cruises in 

 various southern sea areas are cited in the following tableo 



TTtJ 



Former training vessel of the Ministry of Agriculture and 

 Forestry's Fisheries Instituteo 



79 



