Isahaya Bay, fill in of the tidal flats, Japan

An ill conceived sea wall has left for 20 years local people and conservationists angry over loss of fisheries, seaweed catches, migratory birds, while farmers worry over damage to their reclaimed farmland if the gates are opened.

This is a conflict of fishermen, seaweed collectors and conservationists against reclamation of land for agriculture. In 19997, the gates cutting off water to Isahaya Bay were closed, and the Isahaya tidal flat was drained.  The  construction of this dyke by the Japanese government sparked conflicts for twenty years based on very material concerns about fishing and seaweed collecting, and based also on appreciation for pristine nature (marine life and migratory birds). There have ben contradictory court decisions. The bay was brutally closed by a 7 km seawall constructed by the Ministry of Agriculture, Forestry and Fishery on 14 April 1997. What used to be one of the largest and richest staging site of migratory birds with an incredible amount of organisms like molluscs and fishes, was thus turned into farmland. The conflict is between local fishermen, who blame damage to their shellfish and seaweed hauls on changes in the flow of the sea current after the floodgates were closed in 1997 to reclaim part of the Isahaya Bay, and farmers, who settled in the reclaimed area and oppose the opening of the gates, saying that incoming seawater would ruin their farmland. The government is caught by the two conflicting court decisions.In the complicated court battles over whether to open the gates, both fishermen and farmers have won district court rulings in favor of their compensation claims. The government is now obliged to pay compensation to the fishermen as long as the gates are shut.  It was the ¥250 billion government project that divided the fishermen and Saga Prefecture on one hand, and the farmers and Nagasaki Prefecture on the other. (The Japan Times, 22 Nov. 2015). Prime Minster Naoto Kan was a longtime opponent of the reclamation project, which he called a typical case of wasteful public works spending that would only damage the local environment. The Ariake Sea is an important fishery and resource for cultured nori (seaweed). The controversial Isahaya Bay Reclamation Project was blamed with reason for reduced harvests of fish and nori in the sea. The 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 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.
Basic Data
NameIsahaya Bay, fill in of the tidal flats, Japan
ProvinceNagasaki prefecture abd Saga prefecture
SiteIsahaya Bay
Accuracy of LocationHIGH local level
Source of Conflict
Type of Conflict (1st level)Infrastructure and Built Environment
Type of Conflict (2nd level)Aquaculture and fisheries
Wetlands and coastal zone management
Specific CommoditiesFish
Project Details and Actors
Project Details
(Source: The Japan Times, 22 Nov. 2015). The project to reclaim part of the Isahaya Bay on the western tip of the Ariake Sea, which borders Nagasaki, Saga, Fukuoka and Kumamoto prefectures, was ...originally based on a 1952 idea by Nagasaki Prefecture to create more farmland to meet the rising food demand at that time. The national government began the land reclamation work in 1989 — despite criticism that it would damage the local natural environment — and the floodgates were closed in 1997 to halt the inflow of seawater and farming began on the reclaimed land in 2008. The cost was 250 billion Yen (between 3 and 5 billion USD).
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Project Area (in hectares)3,000
Level of Investment (in USD)4,000,000,000
Type of PopulationRural
Start Date1989
Relevant government actorsGovernment of Japan

Ministry of Agriculture, Forestry and Fishery

Nagasaki prefecture

Fukuoka high court

Nagasaki district court
Environmental justice organisations and other supportersWWF Japan, Greenpeace.

Fishermen and seaweed collectors, Saga prefecture.

JAWAN, Japan Wetlands Action Network (1991 - led by marine biologist Yamashita Hirofumi, Goldman Prize in 1998).

Friends of the Earth Japan
The Conflict and the Mobilization
Intensity of Conflict (at highest level)HIGH (widespread, mass mobilization, violence, arrests, etc...)
When did the mobilization beginPREVENTIVE resistance (precautionary phase)
Groups MobilizingFarmers
International ejos
Local ejos
Local scientists/professionals
Forms of MobilizationBlockades
Development of a network/collective action
Development of alternative proposals
Involvement of national and international NGOs
Lawsuits, court cases, judicial activism
Media based activism/alternative media
Public campaigns
Appeals/recourse to economic valuation of the environment
Local seaweed growers maintained blockades leading to the land reclamation site.
Environmental ImpactsVisible: Biodiversity loss (wildlife, agro-diversity), Surface water pollution / Decreasing water (physico-chemical, biological) quality, Large-scale disturbance of hydro and geological systems, Reduced ecological / hydrological connectivity, Other Environmental impacts, Loss of landscape/aesthetic degradation, Waste overflow
Potential: Floods (river, coastal, mudflow)
OtherLoss of wetlands. Damage to migratory birds. "When there was a healthy tidal flat, benthic species functioned as a natural

water purification system. Now, without the healthy tidal flat, concentrations of pollutants in the regulating reservoir

exceed the environmental quality standard by a wide margin, and massive water blooms produce natural toxins

making the water quality even worse. The large volume of polluted water discharged from the regulating reservoir

into the bay can cause red tides. Moreover, the closure of the floodgate caused the sea current to slow, gave rise

to red tides, oxygen deficiency and sedimentation of silt on the sea bed. These have led to die-offs of fish and

shellfish species inflicting damage on the fishing industry almost every year. " [1]
Socio-economic ImpactsVisible: Loss of livelihood, Other socio-economic impacts, Displacement, Loss of traditional knowledge/practices/cultures, Loss of landscape/sense of place
OtherLoss of access to marine resources: fisheries and seaweed
Project StatusIn operation
Pathways for conflict outcome / responseCompensation
Court decision (undecided)
Under negotiation
Development of AlternativesAttempts to get Isahaya Bay into the Ramsar convention.
Do you consider this as a success?No
Why? Explain briefly.Despite some favourable decisions in the courts, the goverment and other court decisions have prevented the opening of the gates. Losses of wildlife and loss of market values of fisheries and nori (seaweed) are very large in the last 20 years.
Sources and Materials

Tide Change in Saga, Japan, by Gavan McCormack, The Asia-Pacific Journal, December 12, 2005, Volume 3 | Issue 12 |
[click to view]

Kim Reinmann, Going Global: The Use of International Politics and Norms in Local Environmental Protests Movements in Japan (on Isahaya Bay Land Reclamation project and on Nagara River Estuary Dam), chapter 4 in Pradyumna P. Karan and Unryu Suganuma, Local Environmental Movements. A Comparative Stdy of the United States and Japan, U.P. of Kentucky, Lexington, 2008 (useful book).


The Japan Times, Resolve the Isahaya Bay standoff, 22 Nov. 2015
[click to view]

The Japan Times, Gridlock at Isahaya Bay, 29 Dec, 2013
[click to view]

Isahaya Bay: Sometimes Local Activists (And Fishermen) Win. Business / Corporate Responsibility. June 30, 2008
[click to view]

Pressure Mounting To Reopen Isahaya Bay, by James Singleton. 23 May 2014.
[click to view]

Media Links

[1] Save! The seas of Isahaya, Awase and Nagashima. 2010
[click to view]

Other Documents

[click to view]

[click to view]

Other CommentsGavan McCormack, 2005: "The Isahaya Tidal Wetlands Reclamation project represents in concentrated form the essence of the construction state, the developmental state that helped drive Japan's economic growth in the 1960s and 1970s but then contributed to its implosion in the 1990s and still has the power to impose economically irrational and environmentally devastating projects. "
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Last update06/12/2016