Most of Japanese salmon-breeders are grouped into 15 associations, gathered themselves in a sort of national federation. The play the part of defending the profession and they deal with commercialization problems. The author paid a visit, in the Shizuoka Prefecture, on one of these groups, the members of which represent 90% of fish-hatcheries and launch on the market 2,500 to 3,000 tons per year. In a general way, the hatcheries of this area are situated on 15 degree C springs. Each exploitation yields an average output of 100 tons. The waters are of excellent quality, lightly acid (pH 6 . 8), allowing fish loads up to 100 kg/m2. Trout attain a fair growth; the market size of 130 g is reached one year after first feeding, with survival rates of 80 to 90%. A breeding test of rainbow-trout in salt water was attempted in 1970-1975; the result was an output of a few tons per year only, which has now become practically non existent. The tendency is rather to replace rainbow-trout by coho salmon and introductions have just been practised in a limited way. Total production in Japan should be twice as high during the next ten years. However, the amount of good quality available water, the need to provide trout with food rich in proteins (of which Japan is rather poor) set a limit to this purpose