Abstract
Survey on distribution of seagrass beds and dugong trenches was performed from February 27 to March 2. 2001 around Libong Island. Trang Province. Thailand. Seagrass beds were observed at southeast to north coast of Libong Island and between Libong Island and the Malay Peninsula. Ten species of seagrasses were identified there. Among the ten species. Halophila ovalis, Cymodocea serrulata and Cymodocea rotundata dominated. The total number of 22 dugongs were observed on February 27 and 28 on and around these seagrass beds by aerial surveys. Dugong trenches were distributed densely in the communities where Halopkila ovalisdominated orHalophilaovalis and Cymodocea serrulata occured together. Therefore, we concluded that dugongs in this study site fed selectively at the Halophila oralis community. We observed the feeding trenches at the nine species of them, but we did not observe the obvious feeding traces of dugongs at Enhalusacoroides. We did not observe the selectivity that dugong prefer to feed at the seagrass bed with less sediment on leaves.
