JAPANESE OYSTER-CULTURE. 
23 
In tlie description of the methods employed in these three localities, it will 
to consider them in the order from the simplest and the most complex, (1) 
(2) Ivusatsu, (3) Nihojima, 
for at Raid a Bay all stages 
of the industry are repre- 
sented in the same oyster 
park; at Ivusatsu the 
methods become more 
complicated,' and finally, 
in the region of Nihojima, 
specialization in the cul- 
tural devices has reached 
a point surpassed in but 
few European localities. 
be best 
Ivaida, 
CULTURAL METHODS OP 
RAID A BAY. 
Pig. 5. — Arrangement of branched collectors as a close-set fence to 
form one of the lines of an oyster park. 
In this well-protected 
region (cf. the accompa- 
nying map of the sea cf 
Aki, fig. 1) there is a large 
area of shallow water, and 
at low tide great flats are 
exposed. Here it has been 
ascertained that the con- 
ditions of water density 
are favorable rather for 
the growth of young oys- 
ters than for the produc- 
tion of “ spat,” but at cer- 
tain points production is 
carried on with marked 
success. The greatest dis- 
advantage of the region is 
the lack of space in which 
the oysters can be kept 
covered by water during 
all times of the month. 
Probably it is for this rea- 
son that the growth of the 
oyster comes to be checked, 
since it is well known that 
they rarely increase in size 
after the end of the second 
year. At this age, then, they are marketed, their small size distinguishing them 
from the oysters of Aki cultivated in other localities. The bay of Raida is, however, 
so fertile in its class of production that it takes a high place among Japanese oyster- 
Ftg. 6.— Arrangement of 
branched collectors in 
close-set hedge, com- 
mon in most types of 
Japanese oyster farms. 
Vertical projection. 
Fig. 7.— Shibi of different rows, new and old, in 
boundary hedge, showing how they are im- 
planted to give mutual support. 
