The technique of restoration of populations of land plants is an old one that is well understood by scientists, agronomists, forestry experts, and the general public. However, only recently has attention been turned to restoring underwater areas with socalled seagrasses. From 1947 onwards, attempts have been made to restore suitable marine areas by using important species; however, only very recently (from August 1973) have large-scale restoration projects been undertaken.
The efforts that have been made to replant various seagrass species by different techniques are reviewed, but only two seagrasses, Zostera noltii and Thalassia testudinum, have been restored on a large scale. Both of these can be restored successfully; however, the seeding method of Thalassia appears to be the most practical operation of all, and the most potentially valuable for future research into large-scale restoration, as it allows flexibility of location and of depth of transplantation, and involves the minimum of damage to the donor site. It also ensures the most rapid regrowth, besides being in the long run the most economical method yet devised of restoring a seagrass community. An economic model (see Technical Appendix to this paper) and analysis for restoration costs are given and finally a wide range of uses of restoration of such beds of seagrasses are enumerated.