Artificial Seaweed Beds as Submarine Ecosystems and their Effects on Commercially Valuable Fisheries Resources in Japan

摘要

In recent years, certain areas of coastal of Japan have experienced a reduction in the occurrence of natural seaweed beds and certain shores have caused increasingly barren grounds. As a consequence, vigorous efforts are being made to recover and re-establish the imperiled seaweed beds and at the same time create new artificial seaweed beds in order to restore the ecosystem functions of the underwater forests. One of these functions is the provision of suitable habitats for fishery resource nursery grounds. New artificial seaweed beds are being created on a nation-wide level. Fishermen have been transplanting parent seaweeds and seeding with spore-bags and lines. The seaweed reefs are being planted with the support of the Fisheries Maintenance Budget at both Prefectural and National levels. As a consequence of the support received, there have been rapid developments made in the technology required for underwater coastal engineering. New materials and designs for construction are being tested to create the artificial seaweed beds and suitable habitats for associated sealife. Furthermore, the concept has been extended to include the creation of marine farms using sea walls, coastal defence and wave breaking structures. The recent constructions of an artifical island to accomodate the new Kansai International Airport is a good example of synergistic development, creating both the structre of the island, coastal defences and also increased seaweed productivity and associated fishery resources.