Proceedings Article | 11 December 2012
KEYWORDS: Satellite imaging, Satellites, Earth observing sensors, Ecosystems, Image processing, Geographic information systems, Water, Remote sensing, Barium, Atmospheric corrections
Seagrasses, marine flowering plants, are widely distributed along temperate and tropical coastlines of the world.
Seagrasses have key ecological roles in coastal ecosystems and can form extensive meadows supporting high
biodiversity. Till now, fourteen seagrass species belonging to four families were found in Vietnam: Halophila beccarii,
H. decipiens, H. ovalis, H. minor, Thalassia hemprichii, Enhalus acoroides, Ruppia maritima, Halodule pinifolia, H.
uninervis, Syringodium isoetifolium, Cymadocea rotundata, C. serrulata and Thalassodendron ciliatum. A total area of
seagrass beds in Vietnam is estimated to be approximately 17000 ha by satellite images and GIS technology. In recent
years, the distribution areas and densities of seagrass beds in Vietnam have been serious decreased compared with those
10-15 years ago. The decline level depended on the impacts by the natural process, the economical activities and the
conservation awareness of local people. Thus, it is different at each coastal area. Generally speaking, the distribution
areas and densities of seagrass beds were decreased by more than 50%. Seagrasses on tidal flats in some areas such as
Quang Ninh, Hai Phong, Phu Quoc seem to be nearly lost. The distribution areas of seagrass beds in 2009 at Tam Giang-Cau Hai lagoon and Cua Dai estuary was decreased by 50-70% of those in early 1990s.
