280 



BULLETIN OF THE BUREAU OF FISHERIES. 



are therefore struck on' the collectors at that time and taken to the place called 

 "ike-ba" (literally living-ground), where they are placed directly on the rather firm, 

 gravelly sea bottom, and allowed to grow there until the cold season of the third 

 year. These "ike-ba" may be some distance from, or quite near, the spat-collecting 

 ground, according to the circumstances of each collector and how and where he can 

 get a good bottom for the purpose. Finally, toward the cold season of the third 

 year the oysters are removed to the "miire-ba," or maturing-ground, which is 

 to receive all that are ready for the market. This ground must, of course, be quite 

 near the culturist, and easily accessible. Figure '2, plate vni, shows oyster grounds 

 at Kusatsu, and conveys a good idea of their extent. 



At.Nihojima, about 2 miles east of Hiroshima, the nature of the oyster grounds 

 has necessitated the development of a most elaborate system of oyster culture. 

 Here the main part of the grounds is in a sheltered inlet, or rather in an enlarged 



itt ; 



- Kunl'MM i-nllt'cinrs arranged after tin- fashion common in Kusatsu. They stand about 3 feet above the bottom aud 

 their tips diverge; the clumps are set 1 or ••> feet apart. 



mouth of a river, which naturally brings down a great deal of freshwater. As 1 



think, for this very reason the spat collecting is done just outside the inlet. Here, in 

 April, w-hen the breeding season begins, bamboo collectors, four or rive in a bundle, 

 are planted in close clusters along the channel to receive the spat. Figure 1. plate ix, 

 shows two of these clusters. At t he end of the breeding season — that is. in the latter 

 part of August — the collectors are uprooted and conveyed inside the inlet, care 

 being taken not to injure the spat upon them. There they tire built into peculiar 

 structures called "tbya," which tire round pyramidal in shape, and measure about 

 .". to 4 feet high and .'> to 6 feet across at the bottom (sec tig. 2, pi. ix. left side). 

 A ''toya" is constructed (cut 8) as follows: In the center are small bamboo collectors 

 of last year on which some young oysters tire still adherent. Outside of these the 

 new bamboo collectors which have just been brought in from the spat-collecting 

 ground with tiny oysters adherent on them are placed in two circles, one outside 



