Seagrass mapping using ALOS AVNIR-2 data in Lap An Lagoon, Thua Thien Hue, Viet Nam

Seagrass canopy plays a critical role in the ecological functions of coastal zones. They supply nursery and juvenile habitats for fisheries, stabilize sediment and provide direct food for dugongs and green turtles. Lap An is the semienclosed lagoon in the South of Thua Thien Hue province with a large area of mangrove and seagrass. This lagoon significantly supports local aquaculture, and is highly important nursery for economic fisheries. However, the reclamation activities of local farmers have disturbed the aquatic habitats, and diminished the seagrass canopy (more than 60% has disappeared from the lagoon). The objective of this research is to detect the distribution of the seagrass, and propose a seagrass-based protected area for conservation purposes. ALOS AVNIR 2 data was utilized to detect the scattered small patches of seagrass. The use of water column correction, principle component analysis, neural network algorithm and ground control points in the field were undertaken to enhance the classification accuracy of the study. This research provides a new approach for detecting seagrass meadows, and contribute toward better integrated management of the coastal zones.