The government will seek the suspension of a reclamation project in Isahaya Bay, Nagasaki Prefecture, to check water quality in a reservoir behind the bay's dike from this week, officials said Wednesday.

The move is aimed at finding the causes of this year's poor seaweed crop in the Ariake Sea.

The Agriculture, Forestry and Fisheries Ministry plans to conduct a 12-day investigation with the Environment Ministry in the 1,710-hectare reservoir and Isahaya Bay, Agriculture Ministry officials said. The investigation will cover water quality, organic materials and nutrient salts in the sludge and soil.

In Tuesday night talks with Toshikatsu Matsuoka, senior vice farm minister, Nagasaki Gov. Genjiro Kaneko conditionally accepted the suspension of the reclamation project.

Kaneko told Matsuoka the prefecture will continue construction in places where the investigation will not be affected and fully resume work on or after March 28.

The 237 billion yen project is designed to create 1,840 hectares of farmland.

The ministry decided to call for the suspension based on recommendations earlier in the day by a ministry task force created to find the causes of poor seaweed crops in the Ariake Sea.

Local seaweed farmers are calling on the government to conduct the investigation by opening the floodgates of the 7,050-meter-long dike, which cuts part of the bay off from the Ariake Sea.

It is unlikely, however, that the gates will be opened fully as task force members oppose it, pointing to subsequent likely risks.

Isahaya Bay is part of the Ariake Sea, an almost landlocked body of water surrounded by Nagasaki, Kumamoto, Saga and Fukuoka prefectures.

Local seaweed farmers allege the sea has been polluted by nutrient-rich waters periodically released from inside the reservoir and have demanded a revival of the original ecosystem in the sea.

More frequent phytoplankton red tides in unusual seasons have been reported by academics, fishermen and local government authorities.

During the task force meeting, Nihon University professor Masami Okamoto, testifying as an expert, warned that unless the floodgates are opened with careful timing, seawater will flood the reservoir rapidly and the gates may break under the pressure.

Isahaya Mayor Kunio Yoshitsugu, also testifying before the panel, urged it not to open the gates, saying they should remain closed to shield the city of Isahaya. He said there is no rationale in the assertion that the poor seaweed crop sprang from the reclamation work.

Nori is a common ingredient in Japanese cooking and is used to wrap some types of sushi. Ariake Sea nori is one of the best-known varieties and the Ariake area is a leading production center.