are areas of water in Japan so designated, in accordance with Section 2 of the 1951 , by the Minister of Agriculture, Forestry and Fisheries in conjunction with the prefectural governor in an effort to protect and cultivate the aquatic animals and plants living on and below the surface.
As of August 2002, there were 55 designated , totalling some , and 65 , the latter comprising 59 riverine surfaces, with a total length of , and 6 lacustrine surfaces, with a protected area of . Representative of each type are areas of the Seto Inland and Ariake Seas, Ibi, Kinugawa, Nagara, and Tenryà « Rivers, and Lakes Biwa and Kasumigaura, respectively.
In these areas, as well as no-take measures, with the harvesting of all or particular species prohibited, and breeding and propagation initiatives, activities including dredging and land reclamation are restricted and regulated.