Tideiand productivity and evaluation on its social significance - taking the case of Tokyo Bay -

20世纪80年代中期以后，短颈蚌的年产量相对稳定在1万吨左右，位于仅次于爱知县的第二大产区。千叶县的生产力是由条件良好的滩地和渔业合作社管理的蛤蜊养殖业务维持的。在这项业务中，幼小的蛤蜊在指定的沿海地区释放，并在几个月后收获。多年来，海草养殖和蛤蜊渔业一直是东京湾沿海居民的重要产业，在木津市沿海地区，尽管进行了前滩填海，但它们仍然很重要。因此，无论是渔业合作社还是地方政府，都从促进当地产业发展和有效利用剩余滩涂的角度出发，采取财政支持放生的方式。此外，休闲蛤蜊采集在Kisarazu地区很受欢迎，由渔业合作社作为合作社的业务进行管理。以Kisarazu渔业合作社为例，每年有8万人来这里采集蛤蜊。这项业务为城市居民提供了享受自然环境的机会，并为维持渔业合作社的利润做出了巨大贡献。这样，潮地的存在不仅有助于维持渔民和渔业合作社的收入，而且还为城市居民提供便利，这对沿海地方社区来说是至关重要的。

Annual production of Short necked clam (Ruditapes philippinarum) is relatively stable around 10,000tons after mid 1980s, that is situated at the second next to Aichi Prefecture. The productivity of Chiba Pref. Is sustained by the existence of good conditioned tideland and also of the clam cultivation business managed by fisheries cooperatives. In this business, young clam is released in the specified coastal area and is harvested several months later. Sea weeds cultivation and clam fishery has been the important industries for many years for the coastal people in Tokyo Bay and they are still important in coastal area of Kisarazu City, despite the reclamation of foreshore has been proceeded. Therefore, not only the fishery cooperatives but local governments has adopted financial support for releasing young clam from the view point of promoting thc local industry and effective utilization of remained tideland. Furthermore, recreational clam gathering is popular in Kisarazu area and is managed by the fishery cooperatives as cooperatives' business. In case of Kisarazu Fishery Cooperative, 80,000 people visit to gather clams every year. This business provides urban people the opportunity of enjoying the natural environment and contributes greatly in maintaining the fishery cooperative's profit. Ln this way, the existence of tideland contributes not only to maintain the income of fishermen and fishery cooperatives but also to provide the amenity for urban people, that can be the essential significance for coastal local communities.