1962 Nippon Suisan Gakkaishi  
CATCH AND CHARACTERISTICS OF THE FISHING GEAR ON THE BOTTOM GILL-NET FISHERY Tsukasa SHIOKAWA** Using the records of commercial catches on the bottom gill-net fishery (Kashi-ami) and using the results of the research of the catches taken by the bottom gill-net (Takasu-ami), the catches and the characteristics of the fishing gears were discussed. The results obtained from this study are as follows: 1) This gill-net (Kashi-ami) is so fished for taking the warm-sea fishes in this region, that the
more » ... ain fishing season is from April to July and poor, in winter, The resources of this fishery with the exception of the stock of Japanese spiny lobster, Panulirus japonicus are stable comparatively (Figs. 1 and 2 ). 2) The type of frequency distribution curve of the catch per a boat-day for a year is like logarithmic distribution but in major fishing season they form logarithmic normal distri bution curve. The average catch is about 9.8kg and the coefficient of variation is 0.9. Accordingly, it is demonstrated that this fishery is very small scale and unstable (Figs. 3 and 4 ). 3) The fishing ability of the net made of nylon is larger than that of cotton, especialy on the moving or active season of the objective fishes (Table 1 ). 4) Though the "Kashi-ami" is chiely fished for taking the coastal resident fishes, the "Takasu -ami" is almost used for the coastal moving fishes and is more selective in its fishing than the former. The catch and coefficient of its variation on the "Takasu-ami" fishery are respectively 1.5 and 1.1 times more than those of the "Kashi-ami" (Fig. 5 and Table 2 ).
doi:10.2331/suisan.28.876 fatcat:fanedftuijgsble57rant7jfoq