278 BULLETIN OF THE BUREAU OF FISHERIES. 



THE OYSTER. 



Oat rut cucullata Horn. 



The oyster has probably been longer under cultivation by man than has any other 

 mollusk. and it is also the most extensively cultivated. As to the former point. 1 

 need only refer to Roman pictures delineating oyster rearing, and as to the latter 

 to the extensive enterprises carried on at the present day in Europe and America. 

 In Japan also the luscious mollusk received an early attention, and its culture is 

 becoming more and more extensive. The first place where this was done systemat- 

 ically appears to have been the neighborhood of Hiroshima, a town about in the mid- 

 dle of the length of the Inland Sea and on the north side of that waterway. There 

 is a record preserved there showing that the art of oyster raising was well understood 

 certainly one hundred and eighty years ago, and the practice is no doubt much older. 

 There were several reasons why it should prosper here, among which may be men- 

 tioned (1) that the sea about there is as quiet as a lake; (2) that the differences of level 

 between the high and low water marks are comparatively great, being 111 to 15 feet, 

 thus exposing a very wide area adapted for oyster cultivation; (3) the bottom of the 

 sea is rather firm there, being composed of finely ground granite; (4) lots were early 

 divided and leased to individuals, thus securing the utmost exertions of those lessees; 

 (5) monopoly was acquired by the people of this region in selling oysters in Osaka, 

 thus ensuring a large market. 



I made in 1894 a careful inspection of the oyster industry of Hiroshima at the 

 request of the department of agriculture of the Japanese Government and wrote a 

 report on it (in Japanese). This has been, in its main outline, together with some 

 valuable additions of his own, put in English by Prof. Bashford Dean, of New York 

 (U. S. Fish Commission Bulletin for 1902, pp. 17-37, pis. 3-7), and the reader may 

 be referred to it for details. 1 shall, however, touch here, though briefly, on various 

 systems carried out around Hiroshima, for they are, after all. the most complete of 

 any known in Japan. 



The simplest method among them is practiced in a village called Kaidaichi, a few 

 miles east of the city of Hiroshima. When the tide is in this bay is a quiet, placid 

 piece of water: one sees nothing unusual unless he looks deep below the surface and 

 notices long lines of bamboo fences. When the tide is out the scene takes on an 

 entirely different aspect. One sees that the entire area, only so recently covered by 

 the water and over which out 1 glided in a boat, seems to be cut up into lots looking 

 verv much like town lots, with streets intersecting. Two examples of these lots are 

 given in cuts 5 and 6. The lines in the figures indicate bamboo collectors on which 

 the oyster spat becomes attached and grows, the full lines representing those that 

 were put up any one year, and the dotted lines those of the year previous. Figure 

 1, plate vni, shows how these bamboo collectors and oyster fields look. From a 

 distance the sight reminded me of nothing so much as vine trellises in the Rhine 

 vineyards. The spat that is collected on these bamboo fences is left to grow on 

 them until the winter of the next year — that is, only a little more than a year from 

 the beginning. Then the bamboo collectors are taken down, the oysters are beaten 

 off and are then ready to be sent to the market. 



The oysters are necessarily small, for unfortunately there is no place in this bay 

 to allow their further growth, as the bottom is too soft and they would become 



