Publication Date

Fall 2013

Degree Type


Degree Name

Master of Science (MS)


Biological Sciences


Leslee A. Parr


Conservation genetics, Dugong, Marine mammal, Microsatellite, Mitochondria

Subject Areas

Conservation biology; Genetics; Biology


The dugong (Dugong dugon) is indigenous to the coastal waters of the Indo–Pacific Ocean and is vulnerable to extinction throughout its range due primarily to anthropogenic effects. In Thailand the population of dugongs is approximately 250 animals and is found in fragmented habitats along the Thai coast. Genetic studies were implemented in this study to assess regional genetic composition and determine if there is variation in the D–loop sequences or microsatellites consistent with philopatry to regions, by males or females, or indicating dispersal. Utilizing D–loop sequences, 27 haplotypes were found that grouped into three haplogroups that were not differentiated by region but did show spatial differentiation when analyzed with F–statistics. Microsatellite analysis provided evidence of three populations – one in the Gulf of Thailand and two in the Andaman Sea (north Andaman Sea and Trang Province). Weak structuring of mtDNA variation occurs between neighboring Andaman Sea regions and may indicate philopatry by females due to high quality seagrass meadows in Trang Province especially. Nuclear DNA analysis provided a signal of dispersal between the two sides of the peninsula explaining how genetic variation has remained at levels above expected for a species with declining numbers. Utilizing established bottleneck tests, no evidence was found indicating a bottleneck in the population, though there was a signal of population decline, especially in the Gulf region. Overall recommendations are for further molecular studies utilizing a greater sample size and additional populations in the Indo–Pacific region to determine historic dispersal and a more comprehensive study of population viability.