title: Feeding behavior of wild dugongs monitored by a passive acoustical method.
abstract: 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.
authors.affiliation: Graduate School of Informatics, Kyoto University, 606-8501 Kyoto, Japan.
authors.forename: Chika
authors.initials: C
authors.lastname: Tsutsumi
authors.forename: Kotaro
authors.initials: K
authors.lastname: Ichikawa
authors.forename: Nobuaki
authors.initials: N
authors.lastname: Arai
authors.forename: Tomonari
authors.initials: T
authors.lastname: Akamatsu
authors.forename: Tomio
authors.initials: T
authors.lastname: Shinke
authors.forename: Takeshi
authors.initials: T
authors.lastname: Hara
authors.forename: Kanjana
authors.initials: K
authors.lastname: Adulyanukosol
mesh_terms: D000162:Acoustics / Q000295:instrumentation*; D000818:Animals; D002940:Circadian Rhythm; D020454:Dugong; D004777:Environment; D005247:Feeding Behavior; D013785:Thailand; D014828:Vocalization, Animal