Aquaculture is gaining importance globally, including salmon farming in Hokkaido. To develop salmon aquaculture in Hokkaido, the distribution of aquaculture operations in 1991, when salmon aquaculture was at its peak, and that in 2019 were compared in terms of geologic formations. River water is more abundant than springwater, although the temperature of springwater is higher than that of river water in winter, making spring-based salmon aquaculture more suitable. Fish farms using both river water and springwater have survived. Hydrogeologic and geologic maps show that many fish farms are on the edge of highlands, terraces, and loamy alluvial fans where groundwater is abundant and easily pumped up. In addition, many fish farms in 2019 were located near volcanic fronts in the foothills, where it is easy to access springwater. Fish farms utilized water from only three rivers, the Ishikari River, upper Tokachi River, and upper Saru River. Many fish farms established at high elevations went out of business, indicating that locations where the air temperature in winter is extremely low and that are distant from city markets are not ideal for aquaculture operations.
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