Ainan Town is the first junction where the Kuroshio Current from the Pacific Ocean flows into the Uwa Sea. With an average water temperature of 28°C in summer and 17°C in winter, the warm, nutrient-rich, oxygen-rich fishing grounds nurture healthy farmed fish that feed well.

The aquaculture fishing grounds are located in the Ashizurimisaki Uwakai National Park, which boasts some of the clearest waters in Japan. The sea in Ainan Town is a rias coast, with water depths of 50 to 60 meters, a perfect environment for red sea bream, which prefer deep water.
Some sea bream producers have set up a large 20m x 20m submerged fish tank, which is unique in Japan, to cultivate sea bream in a more stress-free environment.

In the sea of Ainan Town, the "rapid tide" with high water temperature and the "bottom-entering tide" with low water temperature and high nutrients switch about every half month.
This creates a nutrient-rich and oxygen-rich aquaculture fishing ground, and the incoming and outgoing tides nurture farmed fish with firm flesh. This is a special phenomenon that occurs only in the Uwakai Sea, which has the geographical condition where part of the Kuroshio Current flows into the inland sea, and Ainan Town benefits most from its location at the entrance to the Uwakai Sea.
The fishing grounds of Ainan Town are truly a habitat for sea bream.