Abstract
Some fisheries science research institutes began to study eelgrass bed restoration in the 1970 s. In the 1980s, the Central Research Institute of Electric Power Industry investigated the environmental factors affecting eelgrass bed formation in Odawa Bay and published guidelines for eelgrass bed creation. In the 1990 s, the city of Hiroshima, Hiroshima Prefecture, Kumamoto Prefecture and the Ministry of the Environment in Japan started restoration of eelgrass beds using both transplantation and seeding. The city of Hiroshima transplanted 60, 000 vegetative shoots in an area of 5, 000m2 in order to increase fisheries resources. The eelgrass bed area was enlarged to over 12, 000m2. Marino-Forum 21 elucidated the relationships between the upper depth limit on sandy substratum and wave conditions (1/3 significant wave height with a return period of 5 years: 0.5m, orbital velocity: 0.6m/sec., critical shields number. 0.22), and also between the lower depth limit and net photosynthetic rate (monthly net photosynthetic rate=0 or greater).
