Additionally, the coastal area along the Ariake Sea was where the problem of draining Isahaya Bay arose, when, just after the operation begun, the water contamination strongly influenced the production volume and quality of nori there, and in particular devastated the production area in Nagasaki Prefecture.
また、この有明海沿岸は諫早湾干拓問題で大きく揺れた地域であり、事業開始直後は水質の汚濁などによって海苔の生産量や品質に大きく影響を与え、とりわけ長崎県の産地は壊滅的打撃を受けた。