title: Whistle characteristics of free-ranging Indo-Pacific humpback dolphins (Sousa chinensis) in Sanniang Bay, China.
abstract: Broadband recording systems were adapted to characterize the whistle characteristics of free-ranging Indo-Pacific humpback dolphins (Sousa chinensis) in Sanniang Bay, China. A total of 4630 whistles were recorded, of which 2651 with legible contours and relatively good signal-to-noise ratios were selected for statistical analysis. Of the six tonal types (i.e., flat, down, rise, convex, U-shaped, and sine), flat (N = 1426; 39.45%) was the most predominant, followed by down (N = 754; 23.35%) and rise (N = 489; 12.34%). The whistles showed a short duration (mean ± SD: 370.19 ± 285.61 ms; range: 29-2923 ms), a broad frequency range (fundamental contour ranged from 0.52 to 33 kHz), and two harmonics (mean ± SD: 1.90 ± 2.74, with the maximum frequency of harmonics beyond 96 kHz). Whistles without gaps and stairs accounted for 76.7% and 86.4%, respectively. No significant interspecies differences in frequency parameters were observed compared with S. teuszii, which is inconsistent with morphological taxonomies but confirms phylogenetic results, thus suggesting a close relation between Chinese S. chinensis and Atlantic S. teuszii. Significant intra- and interspecific differences in the genus Sousa were also observed, indicating that animal vocalization may not be limited by genetically determined traits but could also be a function of local habitat adaptation.
authors.affiliation: The Key Laboratory of Aquatic Biodiversity and Conservation of Chinese Academy of Sciences, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan 430072, People's Republic of China.
authors.forename: Zhitao
authors.initials: Z
authors.lastname: Wang
authors.forename: Liang
authors.initials: L
authors.lastname: Fang
authors.forename: Wenjing
authors.initials: W
authors.lastname: Shi
authors.forename: Kexiong
authors.initials: K
authors.lastname: Wang
authors.forename: Ding
authors.initials: D
authors.lastname: Wang
mesh_terms: D000162:Acoustics; D000818:Animals; D002681:China; D004289:Dolphins / Q000145:classification / Q000502:physiology*; D009792:Oceans and Seas; D012815:Signal Processing, Computer-Assisted; D059629:Signal-To-Noise Ratio; D063346:Singing; D013018:Sound Spectrography; D013045:Species Specificity; D013550:Swimming; D013997:Time Factors; D014828:Vocalization, Animal