Feeding behavior of wild dugongs monitored by a passive acoustical method.
Little is known about feeding behavior of wild dugongs (Dugong dugon) because direct measurements of feeding events in the water were scarcely feasible. In this study, the authors achieved the first successful feeding sound monitoring in a seagrass area using a full-band underwater recording system (called automatic underwater sound monitoring system for dugong: AUSOMS-D). In total, 175 feeding sounds were identified in 205 h of recording. Feeding sounds were only detected at night, implying diurnal differences in the feeding behavior of the studied dugong population. Differences in periodicity of feeding sounds suggested that two or more individuals were in the acoustically observable area. Furthermore, a feeding position monitored by two AUSOMS-Ds was used to calculate source levels of dugong feeding sounds. Assuming spherical_propagation, source levels were measured between 70.6 and 79.0 dB rms re 1 microPa/square root of Hz.
Tsutsumi
Chika
C
Graduate School of Informatics, Kyoto University, 606-8501 Kyoto, Japan.
Ichikawa
Kotaro
K
Arai
Nobuaki
N
Akamatsu
Tomonari
T
Shinke
Tomio
T
Hara
Takeshi
T
Adulyanukosol
Kanjana
K
D000162:Acoustics / Q000295:instrumentation*; D000818:Animals; D002940:Circadian Rhythm; D020454:Dugong; D004777:Environment; D005247:Feeding Behavior; D013785:Thailand; D014828:Vocalization, Animal