Analysis of stomach contents of dugongs (Dugong dugon) from Gulf of Thailand

Abstract

During October 1994-March 2001, six stomach samples of stranded dugongs were collected from 4 provinces in the Gulf of Thailand - 3 from Rayong Province, 1 from Chonburi province, 1 from Chumporn Province and 1 from Surat Thani Province. Based on the inspection of physio/morphological characters of leaves and epidermal cells, seagrass fragments were identified down to genus/species under stereo-and compound-microscopes. Five species of seagrass were found in the dugong stomachs, their biomass were determined in terms of dry weight. The percentage of dry weight of each genus/species found in the stomach contents was as follows : Halophila (H. ovalis and H. decipiens) 9.97-55.43%, Halodule uninervis 0-37.43%, Thalassia hemprichii 0-2.25%, and Enhalus acoroides 0-13.74%. The frequency of occurrence of seagrasses in the stomachs ranged from the maximum to the minimum as follow : Halophila, Halodule, Enhalus and Thalassia. In addition, rhizome (13.99-45.49%) and algae (3.33-16.41%) were found in all stomach samples.