Pressure Mounting To Reopen Isahaya Bay

Economy Society Culture

There is no better example of the juggernaut that is Japan's public works system than the Isahaya Bay Reclamation Project, a massive endeavor to fill in the tidal flats of Isahaya Bay for agricultural use. Alex Kerr gives an enlightening account in his book Dogs and Demons: The Fall of Modern Japan of how the project, part of a 1952 initiative by Nagasaki Prefecture to boost rice production, was propelled by bureaucratic inertia despite protests by the fishing industry and demographic changes that rendered such large-scale (and environmentally altering) projects obsolete. The project, which was taken over by the Ministry of Agriculture, Forestry, and Fisheries, went from concept to reality in 1997 when a line of roughly 300 steel plates, known as the "guillotine," in one fell swoop cut off Isahaya Bay from the rest of the Ariake Sea. 

The reclamation project created a holding pond for irrigation and over 600 hectares of arable land; farmers began tilling their new plots in 2008. But doing so required the construction of a 7-kilometer long dike across the bay that continues to choke off what is left of one of Japan's largest and most vibrant wetlands. Individuals involved in fishing and nori (laver) farming around the Ariake Sea, which Isahaya Bay opens into, have maintained fierce opposition to the dike, claiming the disruption it causes to currents has reduced catches and hindered seaweed production. These groups have pushed for the government to open the dike’s two floodgates, a move that the government has staunchly opposed, citing potential damage to farmland from an influx of seawater. 

Farmers, backed by the government, and the fishing industry have battled in the courtroom since the inception of the project. In 2010,  Prime Minister Kan Naoto allowed a Fukuoka High Court decision, ordering the floodgates open for five years to investigate alleged damage to fisheries, to stand unopposed. In response, farmers petitioned the Nagasaki District Court to order an injunction blocking the opening of the gates, which was granted. The government cited the lower court’s decision as reason to sit on its hands and allow the three-year deadline set by the Fukuoka court to pass. An order by the Saga District Court in April of this year requires the state to begin paying a daily fine of ¥490,000 yen, ¥10,000 to each of the 49 complainants in the case, in two months unless the floodgates are opened. The government has yet to say if it intends to honor the decision.

There is no doubt that overall catches in the Ariake Sea have been in steady decline since the 1980s.  Research has pointed to a connection between low oxygen levels in seawater, red-tide outbreaks, and environmental changes due to land reclamation. The issue predates the Isahaya project, but in the nearly two decades since the bay was cut off, there have been noticeable drops in shellfish hauls, with collection of some species, such as the tairagi (pen shell), being halted. Nori production, while relatively steady, has twice had harvests severely affected by red tides.

A related but poorly understood issue is the role Isahaya Bay plays as a spawning sight and nursery for fish and bivalves. The bay was called the “womb” of the Ariake Sea by locals involved in the fishing industry and it is no stretch to think that fish stocks are being adversely affected by blocking off access to the environment of the bay. 

Research has also pointed to the dike’s potential effects on currents throughout the entire Ariake Sea. The seawall shortened the bay’s tidal prism, the difference in the volume of water between high tide and mean low tide, reducing the force of water pushed through the sea and weakening currents. Reduced water flow produces a favorable environment for red-tides and other events that impact fish and wildlife. 

In light of these issues, the government’s refusal to open the flood gates is hard to understand. Despite the obvious need to look into the environmental health of the bay and surrounding sea more thoroughly, officials continue to argue that the reclamation project has had no adverse impacts. A Japanese-language website run by the Nagasaki prefectural government—a message at the top of the site plaintively asks, “Why destroy our future?”—provides a wide range of facts, figures, and scenarios to support the state’s claims. Realistically, though, the data lacks the necessary scope to make the state’s claims credible.

Arguments for opening the gates are reasonable and cast doubt on the government’s motives for siding with a small number of farmers in one prefecture over investigating an issue impacting the fishing industries in three prefectures (the Ariake Sea is bordered by Nagasaki, Saga, and Kumamoto). The state’s disregard of credible concerns by the fishing industry is made all the worse by a willingness to use a district-level ruling to ignore a high court order, which sets a dangerous precedent and does nothing to remedy the deep rifts formed between local communities.

Japan is as a signatory to the Ramsar Convention, which promotes the sustainable utilization of wetlands. A concerted effort to address the situation seems in order. Projects to restore wetlands, such as an ecological park in Suncheon Bay in South Korea, have shown that restoring the natural environment has benefits for local economies through tourism and fishing. The benefits of restoring what remains of the wetlands in Isahaya Bay would serve to complement farming; the government should not be quick to disregard them.

It’s hard not to see the state’s stubborn stance as a carryover from decades of pushing the Isahaya Bay project. The only logical way to settle the issue for good is to open the gates, with proper efforts to ensure that farmland is protected and environmental changes are properly monitored.

Considering global environmental trends and Japan’s demographic slide, returning nature to as close to an original state as possible is the best long-term policy.

(Banner photo: The 7-kilometer dike and reclaimed land of Isahaya Bay. © Jiji Press.)

environment farming fishing Isahaya Bay Ariake Sea wetlands