Abstract
In recent years, ayu (Plecoglossus altivelis Temminck et Schlegel) breeding has been reorganized into an industry characterized by areal differentiation. The writer investigated the reorganization of the ayu breeding area in the Nakagawa plain, Tokushima Prfecture, which has the largest ayu breeding industry in Japan. The results are as follows.
Ayu breeding in the Nakagawa plain has rapidly developed since 1964 under a strong cooperative system of quality control and sales. But ayu breeding is not uniform; it varies from one area to another with natural and social conditions.
The ayu breeding industry in the Nakagawa plain has, from its beginnings, had the areal differences of management style on the two sides of the Nakagawa river, because one has an underground water supply and the other does not. Since then, the introduction of a cooperative system of quality classification and of sales, accompanied by governmental formation of leading breeding areas, hasexpanded and strengthened the areal differences in the management system. At the same time, the introduction has made clear the differences in the distribution systems on the opposite sides of the river.
Since the first oil crisis, the ayu breeding industry has need a reduction in production cost or to cover rise of materials costs and the fall of wholesale prices for ayu. The reduction in production cost with the internal expansion has been more important. Basically ayu breeding depends on underground water conditions, which along with management techniques can make the difference between profitability and loss.
Areal differentiation of the ayu breeding industry in the Nakagawa plain has ideutified six districts: the left and right sides of the river upstream, midstream, and down stream. As factors in areal differentiation, water conditions are identified as the main factor and cooperative distribution as the secondary factor.
