Restoring eelgrass involves two techniques: Transplanting adult shoos or seeding.
Adult shoots can be collected from existing eelgrass meadows or saved from free floating after they’ve been uprooted from a wave or weather event. In most cases divers can free-plant eelgrass shoots in moderate to low energy sites but sometimes rocks are used to help a bundle of shoots in place until they root. Eelgrass shoots can also be attached to mesh metal frames with biodegradable paper. As the eelgrass roots itself the biodegradable string disintegrates and the metal frames can be removed.
Between early and late summer, when the temperature is right existing eelgrass beds actually flower and produce seeds. These seeds are harvested and can be spread by hand from a boat; or dropped from the plats themselves when attached to mesh bags suspended from a buoy. (seagrassli.org)