A. Net Fisheries 



There are two types of net fisheries Jiaving the tunas as their object. The first is 

 that called the set-net or trap fishery, where the net is permanently fixed at a definite location. 

 The second includes fisheries using movable nets, not fixed in one place, and it comprises 

 round haul nets, drift nets, and gill nets. 



1. Stationary net fisheries 



An example is the large set-net. This type of net is held at one location by the use 

 of anchors and floats and sinkers, so it is necessary that the place where the net is set up be not 

 very deep. As it is naturally impossible to move the net at will, unless it is set up across paths 

 travelled by the fish, it will be difficult for it to attain its objective of catching fish. 



These two conditions place basic limitations on the establishment of tliis type of 

 fishery. Places which fulfill these conditions are not to be found everywhere but are naturally 

 extremely limited. 



Places which meet the above two requirements, that is, locations suitable for the 

 set-net fishery, are either on coasts where the water is comparatively deep close to shore, 

 where the effect of run-off from the land is small, and where the coast faces directly on areas 

 of warm current, or they are at places having such topography as the tips of capes or penin- 

 sulas at the mouth of large bays. However, even if these conditions are perfectly met, if the 

 current jind tides in the area are very strong, it will be impossible to set up the gear and the 

 location will, of course, be unsuitable as a fishing ground. 



Thus this type of gear does not have the positive character of chasing and catching the 

 fish, but rather waits for the fish to come of its own accord into the net. Consequently, because 

 of changes in oceanogr aphic conditions and abnormalities in the weather, even though a net of 

 the same construction is set up in exactly the same place, the catch will be good or bad from 

 year to year and fluctuations in the catch will be difficult to avoid. The catch of such gear is not 

 limited to the tunas, but other fish such as yellowtail and skipjack large enough to enter the net 

 will all be taken by this type of fishery. 



As this net is on a large scale it requires a considerable amount of capital to 

 establish one. It may be thought that large sums of money can be earned in the course of one 

 night with this type of gear, but when poor fishing continues for sometime and there is damage 

 from rough weather, it is often found that one fine morning the whole property has been lost. 



As the figure shows (Translator's note: figure onnitted), the net consists of two 

 parts, the lead and the heart. The lead cuts off the path of the fish and acts to direct them into 

 the heart. 



When a tuna comes swimming along and encounters the lead, he is frightened by the 

 net and tries to escape, follows the net out to sea, and at last enters the heart of the trap. 

 When fish enter the heart of the trap, a lookout who is on watch signals at an appropriate time 

 to the tender boat. The boat is standing by the mouth of the heart and when the signal is re- 

 ceived the men in the boat quickly close the opening of the heart so that the fish cannot escape. 

 They then gradually haul the net in such fashion that the fish are driven into the bunt from which 

 they are brought into the boat by means of gaff hooks. 



There are among the tunas, as is set forth in a later section, several species. The 

 different species each have their different habits. The bigeye tuna, the albacore, and the 

 yellowfin tuna do not often approach coasts suitable for the use of large set-nets and therefore 

 they are hardly taken by this type of fishery. Immature yellowfin, however, do tend to enter 

 coastal waters and at their immature stages they are often taken. The black tuna and some of 

 the spearfishes characteristically enter coastal water areas and therefore the catch of the set-net 

 is principally these species. 



