II. Fishing grounds and oceanographic conditions, 



(l) Concerning the summer fishery 



(a) Oceanographic conditions and coastal fishing grounds 



As was stated earlier^ the summer fishery for albacore 

 by fishing vessels from this prefectirre is carried on in 

 conjunction with the skipjack fishery, and for this reason 

 its fishing grounds do not ordinarily extend beyond the range 

 of the skipjack groundSo Before the development of the winter 

 albacore fishery, these were the only albacore grounds to 

 which any importance was given. From 1935 to 1937 (particularly 

 in 1937) the value of these fishing grounds decreased sharply, 

 quickly arousing the concern of persons engaged in the fishery. 

 Some pessimists feared tnat the fishery might die out altogether, 

 but a natural revival of the fishery in 1938 brought back their 

 former value to these grounds. The coastal fishing grounds 

 have thus undergone a remarkable rise and decline, but the 

 question of the movements of these fishing grounds and their 

 relation to oceanographic conditions remains. As has been 

 stated a number of times previously, these fisning grounds 

 fall witnin tne sphere of the skipjack grounds. The fishing 

 season is short, being only 3 months, from the end of April 

 to July, Ihis is not a well-rounded study, but the general 

 outline of tne fishery is roughly as follows: 



Range of water temperatures within which catcnes are 

 made — 18° to 21^°, 



Area of good fishing grounas -- from 30° to 36° N, 

 latitude and from liiO° to 152° E, longitude. 



Range of favorable water temperatures — 19° to 23°o 



Period of greatest catch -- from middle of May to 

 middle of June, 



The fishing grounds first appear in April about 1^0 to 

 I1.50 miles east of Cape Nojima, (Ihe first catches are some- 

 times made in the middle of liarch in the vicinity of Hachijojima 

 and Aogashima, but ordinarily no fish are caught in this 

 vicinity after the first of April, ) In May the albacore 

 appear in the coastal waters around Cape Nojima, and in June 

 and July they pass northeastward through the coastal waters 

 of the Boso region and disappear, only a very few of them 

 appearing in the Northeastern Sea Area in August and September, 

 (Of course, this description does not obtain for years like 

 1937> when the summer albacore fishery presented abnormal 

 conditions, ) 



