title: Estimated detection distance of a baiji's (Chinese river dolphin, Lipotes vexillifer) whistles using a passive acoustic survey method.
abstract: Source levels and phonation intervals of whistles produced by a free-ranging baiji (Chinese river dolphin) were measured in the seminatural reserve of Shishou in Hubei, China. A total of 43 whistles were recorded over 12 recording sessions. The mean dominant frequency (the frequency at the highest energy) was 5.7 kHz (s.d. = 0.67). The calculated source level was 143.2 dB rms re 1 microPa (s.d. = 5.8). Most phonation intervals were shorter than 460 s, and the average interval was 205 s (s.d. = 254). Theoretical detection range of baiji's whistle was 6600 m at the present study site, but it could reduce a couple of hundred meters in practical noisy situation in the Yangtze River. Sporadic phonation (205 s interval on average) with relatively faint signal of baiji was considered to be difficult to be detected by a towing hydrophone system. Stationed monitoring or slow speed towing of hydrophones along the river current is recommended.
authors.affiliation: Institute of Hydrobiology, The Chinese Academy of Sciences, Wuhan 430072, People's Republic of China.
authors.forename: Kexiong
authors.initials: K
authors.lastname: Wang
authors.forename: Ding
authors.initials: D
authors.lastname: Wang
authors.forename: Tomonari
authors.initials: T
authors.lastname: Akamatsu
authors.forename: Kaoru
authors.initials: K
authors.lastname: Fujita
authors.forename: Rika
authors.initials: R
authors.lastname: Shiraki
mesh_terms: D000162:Acoustics / Q000295:instrumentation*; D000818:Animals; D002681:China; D004289:Dolphins; D004777:Environment; D005260:Female; D009622:Noise; D045483:Rivers; D012767:Ships; D014828:Vocalization, Animal