Stomach contents of dugongs (Dugong dugon) from Trang Province, Thailand

Abstract

Six stomachs of stranded dugongs, collected in Trang Province, Thailand during January 1997- January 1999, were inspected. Based on physio/morphological characters of leaves and epidermal cells, seagrass fragments were identified down to species under stereo - and compound-microscopes. Nine species of six genera of seagrasses were found in dugong stomachs, 4-6 species each and their biomass was determined in terms of dry weight. The percentage dry weight of each species found in the stomach contents was as follows: Halodule spp. 0.84-44.99%, Halophila ovalis 3.11-29.60%, Thalassia hemprichii 3.50-28.69%, Cymodocea spp. 5.06-42.52%, Syringodium isoetifolium 0.42- 22.39%, and Enhalus acoroides 31.76-41.39%. The biomass of Halophila decipiens was not determined because of its scarcity. Four dugongs fed mainly on the dominant species (H. ovalis, E. acoroides, Cymodocea. serrulata, and Halodule pinifolia) available in the catch areas whereas the another two dugongs may have selected their target seagrasses from the existing species. Rhizome appeared to be the importance part of dugong dietary. Remarkably, the dominant available seagrass species in the catch areas contributed to be the most heavily utilized genera of the dugongs in Trang waters.