Stranding records of dugong (Dugong dugon) in Thailand

Abstract

The information of stranded dugongs (Dugong dugon) has been recorded by the Phuket Marine Biological Center from the Andaman Sea coast and the Gulf of Thailand. The data were obtained from the records of fishermen, stranded dugongs, and specimens preserved in the museums, temples or institutions. Two hundred and eighty two records of stranded dugong were recovered from 1962 through February 2008. Of these 71.6% of the records were from the Andaman Sea, 25.8% of the records from the Gulf and 2.6% of the records had no information of the stranding place. Some 22.7% of the records were male, 22.3% female and 55.0 % of unidentified sex. The highest record of stranded dugong per year was in 1996 and the place where most stranding was found was in Trang province. The mean length of stranded mature dugong was 2.52±0.18 m in male (n=12) and 2.5±0.16 in female (n=19) while the maximum length was 2.94 m. The smallest calf was 0.97 m in length and 14 kg in weight. The maximum weight of 310 kg was recorded in a male dugong with 2.75 m in body length. The number of stranding sizes of the dugong ranging from 0-1.5 m long, >1.5-2.0 m long and >2.0-3.0 m long was 20.8%, 31.7% and 47.5%, respectively (n=101). The body length (m) and body weight (kg) relationship equation was Y = 19.108 x 2.8103 and R = 0.945 (n=65). Most dugongs died by unidentified cause. However a generally high proportion of deaths was from gillnets among identified causes of the stranding.