Japan's Supreme Court has dismissed an appeal by local fishermen, who demanded the opening of floodgates at a reclaimed section of the Isahaya Bay in Nagasaki Prefecture, western Japan.

Chief Supreme Court justice Nagamine Yasumasa made the judgment on Thursday. The decision will now become final, nullifying a previous court ruling, which ordered the government to open the floodgates in favor of local fishermen.

In the controversial reclamation project in the Isahaya Bay, the government closed the gates along a dike in 1997 to prevent floods and to expand farmland.

A group of local fishermen filed a lawsuit to have the gates opened, insisting the closure had caused serious damage to the local fisheries industry.

Upholding the plaintiffs' demand, a court ruling in 2010 ordering the state to open the gates was finalized, as the central government at that time did not appeal.

But in a different lawsuit filed by a group of local farmers on the reclaimed land, an opposite court ruling was handed down, banning the opening of the floodgates. This ruling was also finalized, so two conflicting rulings have existed.

The central government which is in favor of the closed floodgates filed a counter-lawsuit to have the pro-opening ruling nullified.

The Fukuoka High Court last year acknowledged the government's case and nullified the ruling to open the gates.

Its ruling said that compared with the situation at the time when the court had ordered the opening of the gates, the effect of their closure on local fisheries has decreased, while predicted troubles have been increasing for the reclaimed farmland and disaster management efforts, if the floodgates are opened.

The fishermen then appealed to the Supreme Court.

With Thursday's Supreme Court decision, the government's victory was finalized in a series of court battles, and the contradictory court decisions were effectively integrated in favor of closing the gates.

After the Supreme Court decision, Nagasaki Prefecture Governor Oishi Kengo said he hopes the government and relevant entities will try to revitalize the Ariake Sea, including the Isahaya Bay, without opening the floodgates based on the final court decision.

Governor of neighboring Saga Prefecture Yamaguchi Yoshinori told reporters that he is not satisfied with the court decision that upheld the claim of the government which had not agreed to settle the lawsuit through negotiation.

Agriculture and fisheries minister Nomura Tetsuro told reporters that his ministry will make further efforts to promote the local fisheries and agriculture industries by keeping in mind the hopes and efforts of local people to restore the environment of the Ariake Sea.