Just when criticism of a contentious land reclamation project in Nagasaki Prefecture's Isahaya Bay appeared to have blown over, the issue has been rekindled with reports that large amounts of cultivated seaweed in the Ariake Sea, which flows into the bay, are losing their color and yellowing.

Critics say the dike erected in April 1997 to seal off the part of the bay earmarked for reclamation has effectively stopped the flow of good quality water into the sea.

The complex water-management projects related to the reclamation project have led to a disruption of the environment and the discoloration of the ribbonlike seaweed, called laver, which is a traditional companion to rice on the Japanese table, they charge.

The direct reason for the discoloration is the lack of nutrients such as phosphorus and nitrogen in the seawater. Opponents to the reclamation project also note that catches of shellfish in the area have dwindled in recent years.

In the season's fifth round of bidding for laver held Thursday in Yanagawa, Fukuoka Prefecture, three fishery cooperatives taking part were able to put on the auction block 36 million sheets of laver -- about 15 percent of the amount brought in for bidding in the same period last year. Total bids also plunged to roughly 300 million yen, or 10 percent of last year's figure.

The situation has become so serious that the governors of the four prefectures along the sea -- Fukuoka, Saga, Nagasaki and Kumamoto -- traveled to Tokyo the same day to demand that the central government take action.

While the Ministry of Agriculture, Forestry and Fisheries has launched an investigation into the sudden discoloration and is promising to take steps to rectify the matter, Agriculture Minister Yoshio Yatsu and top officials of the Liberal Democratic Party have also said they may consider opening the dike's floodgates to conduct an investigation if necessary.

But many lawmakers have shown concern over the direction the issue might take, with some members of an LDP panel on the laver problem cautioning against jumping to conclusions and opening the gates before a causal relationship is established.

Some lawmakers urged the ministry to handle the matter in a way that will not lead to all-out opposition to public works projects, according to ministry sources.