Pilot experiments on planting seedlings and small seagrass propagules in western Australia

The aim of this study was to investigate characteristics of some south-west ern Australian seagrasses that might be useful for further investigation wi th respect to restoration. Although seeds and fruits of seagrass species ma y be useful for producing propagules for planting, their collection is base d on knowing when they become available. Posidonia australis, P. angustifol ia and P. coriacea flower profusely annually, but P. sinuosa does not. Once collected, the fruits dehisce in a few days and are ready for planting. It was found that the best way to plant Posidonia seedlings is in clusters in Growool blocks but the rhizomes do not spread quickly. Single Posidonia se edlings, when planted out, were not successful and neither were naturally c olonizing seedlings of Posidonia sinuosa in unexposed unvegetated areas. Su ccessful planting of seedlings and sprigs of Amphibolis in matting needs mo nths of calm weather for them to spread out from their attaching matting wh ich must be very securely attached to the substratum. Little success was ac hieved in growing Amphibolis. In a search for Halophila ovalis seeds, few w ere found because of the patchy nature of their fruiting and small size. Ge rmination was slow but 63% germinated within 6 months. (C) 1999 Elsevier Sc ience Ltd. All rights reserved.