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  • Country: 
  • Site number: 
  • Area: 
    24 ha
  • Designation date: 
  • Coordinates: 
    37°49'N 139°13'E
Materials presented on this website, particularly maps and territorial information, are as-is and as-available based on available data and do not imply the expression of any opinion whatsoever on the part of the Secretariat of the Ramsar Convention concerning the legal status of any country, territory, city or area, or of its authorities, or concerning the delimitation of its frontiers or boundaries.


Hyo-ko. 30/10/08; Niigata; 24 ha; 37°50'N, 139°14'E Habitat/Species Management Area, Natural Monument. Irrigation reservoirs created artificially in the Edo Period (1603-1867) and, since 1990-2000, a bird sanctuary located in the centre of Niigata Plain in Agano City, fed by the Oodoori river . IUCN Red-listed vulnerable species like Steller's Sea Eagle (Haliaeetus pelagicus) and Baikal Teal (Anas formosa) are found here, as well as Tundra Swans Cygnus columbianus above the 1% threshold. The site includes some nationally protected flora species as well. A marshy vegetation serves as habitat for 100 bird species for wintering purposes, aquatic plants and fish species. Hunting is prohibited at the site and local residents are involved in its conservation. Eutrophication and nearby residential development are seen as potential threats. A management plan is anticipated to enter into force in October 2008. Ramsar site no. 1842. Most recent RIS information: 2008.

Administrative region: 
Niigata Prefecture

  • National legal designation: 
    • National Natural Treasure
    • Special Protection Area of National Wildlife Protection Area
  • Last publication date: 


Ramsar Information Sheet (RIS)