May and after a diet of sardines, powdered silkworm chrysalises and 
sweet potato flour were gathered when about 12 - 16 centimeters long and 
15-37 grams in weight. 
Several species of trout and salmon (both inland and sea varieties) 
were reared, A major part qf this production was the rearing of spawning 
adult fish and the hatching of young for the purpose of stocking rivers 
and lakes. In 1936 there were reported to be 217 hatcheries which pro¬ 
duced 106,655,000 individual fish and 361 rearing ponds producing 186,000 
kilograms of fish. Hokkaido and Yamagata prefectures had the largest 
number of trout and salmon hatcheries and rearing ponds although they 
were numerous throughout northern and central Japan. 
Among the lakes in which trout (ame masu) was reared in considerable 
amounts are Lakes Biwa (Shiga Prefecture), Ashi (Kanagawa Prefecture), 
Shiahaku (Hokkaido), Haruma (Gumma Prefecture), Chuzuji and Hojiri and 
Kieaki (Nagano Prefecture). Rainbow trout (introduced from the United 
States in 1877) was stocked in Lake Inawashiro (Fukushima Prefecture) 
and Lake Towado (Akita-ndomori); river trout ( hime masu ) was reared in 
Tow&do and Chuzuji Lakes. 
Aquiculture in lakes and large marshes (not only trout and salmon 
but also other species including eel, carp and ayu) is in most cases 
conducted by some government or public organization for public benefits 
whereas the cultivation of fish in small ponds, reservoirs or rice fields 
* 
is largely done by private enterprise. Prefectural governments through 
their fisheries experiment stations, fishery associations, municipalities 
and villages and fishery unions have all helped in the stocking of lakes 
- 76 - 
16-031 PlOO bu 
