This series of images of southwestern Japan shows how one change can have far-reaching consequences.
The Ariake Sea is an important fishery and resource for cultured nori (seaweed). The controversial Isahaya Bay Reclamation Project has been blamed for recent reduced harvests of fish and nori in the sea. A dike across Isahaya Bay, which was built to create more farmland, has reduced the tidal current mixing of the sea. These weaker tidal currents have led to abrupt changes in the marine environment.
The 7-kilometer sea wall (dike) was completed in April 1997, cutting off Isahaya Bay from the waters of the Ariake Sea. It separated thousands of hectares of tidal flats from the Ariake Sea and turned what was once Japan’s largest area of tidal lands into 1,500 hectares of farmland.
In the Landsat series of images, the Ariake Sea is the large body of water, and Isahaya Bay lies to its west. The dike can be seen as the straight line in the 2003, 2011, and 2013 images, separating dark blue from light blue colored water. Black or very dark blue indicates deep water, and light blue represents shallow water. Forested areas are green, and urban areas are pink. Cropland is distinguished by its rectangular pattern: green shapes are fields with crops, and pink shapes are fields with no crops growing at the time of the image.
(Black stripes run through the images because of the Scan Line Corrector failure on Landsat 7 in May 2003.)
Azuma, M., 2003, The Isahaya land reclamation project and the “Ariake Sea Disaster”—a proposal for sustainable ecosystem management of the Ariake Sea: Japanese Journal of Limnology, v. 64, no. 3, p. 209–217.
Cudmore, W.W., [n.d.], Evaluating human impacts: Salem, OR, Northwest Center for Sustainable Resources, available at https://atecentral.net/r3388/ncsr_human_impacts. (Accessed January 31, 2013.)
Hempel, J., 2002, Thirty-year fight pits activist, dam interests: San Jose Mercury News, available online at https://projects.journalism.berkeley.edu/nagasaki/stories/activist.html. (Accessed February 1, 2013.)
Ishizaka, J., Kitaura, Y., Touke, Y., Sasaki, H., Tanaka, A., Murakami, H., Suzuki, T., Matsuoka, K., and Nakata, H., 2006, Satellite detection of red tide in Ariake Sound, 1998–2001: Journal of Oceanography, v. 62, p. 37–45.
The Japan Times, 2013, Court bars opening of Isahaya Bay dike: The Japan Times Web page at http://www.japantimes.co.jp/news/2013/11/12/national/court-bars-opening-of-isahaya-bay-dike/#.Usr2NPRDtrN. (Accessed January 6, 2014.)
The Japan Times, 2013, Gridlock at Isahaya Bay: The Japan Times Web page at http://www.japantimes.co.jp/opinion/2013/12/29/editorials/gridlock-at-isahaya-bay/#.Usr2_PRDtrN. (Accessed January 6, 2014.)
The Japan Times, 2018, Court rules Isahaya Bay floodgates must remain closed, ditches fine paid to fishermen: The Japan Times, accessed February 4, 2019, at https://www.japantimes.co.jp/news/2018/07/30/national/crime-legal/court-....
JAWAN, [n.d.], Isahaya Reclamation Project—Why it still matters 11 years after the shut-down: Japan Wetlands Action Network, available online at http://www.jawan.jp/e/news/081015isahaya.html. (Accessed February 1, 2013.)
JAXA, 2006, Ariake Sea captured by AVNIR-2: ALOS Research and Application Project, available online at http://www.eorc.jaxa.jp/ALOS/en/img_up/av2_ariake_tide.htm. (Accessed February 1, 2013.)
Kingston, J., 2004, Japan’s quiet transformation—social change and civil society in the 21st century: New York, RoutledgeCurzon.
Knight, C., 2010, Natural environments, wildlife, and conservation in Japan: Asia-Pacific Journal, Japan Focus, available online at http://japanfocus.org/-Catherine-Knight/3292. (Accessed February 1, 2013.)
Lee, S., Lie, H.-J., Song, K., and Cho, C.-H., 2010, A tale of two coasts—Tidal modification in Saemangeum and Isahaya, in Ishimatsu, A., and Lie, H-J., eds., Coastal environment and ecosystem issues of the East China Sea: Tokyo, TERRAPUB and Nagasaki University, p. 91–109.
Nakata, H., Mishina, H., Takahashi, T., and Hirano, K., 2010, A newly emerging environmental issue—Development of hypoxia in the bottom water of Ariake Bay, in Ishimatsu, A., and Lie, H.-J., eds., Coastal environment and ecosystem issues of the East China Sea: Tokyo, TERRAPUB and Nagasaki University, p. 1–12.
NOAA, 2013, A “red tide” is a common term used for a harmful algal bloom: NOAA National Ocean Service, available online at http://oceanservice.noaa.gov/facts/redtide.html. (Accessed February 1, 2013.)
UNEP, 2005, Coastal areas—Isahaya Bay, Japan, in One planet, many people—atlas of our changing environment: Nairobi, Kenya, United Nations Environment Programme (UNEP), p. 106–107.
Yuk, J., Choi, B.H., and Kim, K.O., 2010, Changes of tides in Isahaya Bay due to a barrier: KSCE Journal of Civil Engineering, v. 15, no. 3, p. 427–437.