title: Passive acoustic survey of Yangtze finless porpoises using a cargo ship as a moving platform.
abstract: In order to periodically investigate the population and distribution of the Yangtze finless porpoise (Neophocaena asiaeorientalis asiaeorientalis) in its main distribution range in the Yangtze River, a passive acoustic system deployed on a cargo ship as a moving platform, rather than a dedicated research ship, was developed. A stereo acoustic event data-logger (A-tag) was installed on the cargo ship to passively detect phonating animals. In three surveys carried out in the Yangtze River from Wuhan to Shanghai, an average of 6059 clicks in each survey and 284 porpoises in total were acoustically detected along an 1100-km stretch. The animals were detected frequently in most of the survey range except two "gap sections" with 40 and 60 km lengths, respectively, where no animals were detected in all three surveys. Detected group sizes of the animals in each 120-s time window were not significantly different among the surveys, but the distribution pattern was different and suggested seasonal migration. The cargo ship based passive acoustic survey was effective in detecting phonating animals and can potentially monitor the distribution and population trend over time. Compared to surveys that used dedicated research ships, the present method is more cost effective.
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: Lijun
authors.initials: L
authors.lastname: Dong
authors.forename: Ding
authors.initials: D
authors.lastname: Wang
authors.forename: Kexiong
authors.initials: K
authors.lastname: Wang
authors.forename: Songhai
authors.initials: S
authors.lastname: Li
authors.forename: Shouyue
authors.initials: S
authors.lastname: Dong
authors.forename: Xiujiang
authors.initials: X
authors.lastname: Zhao
authors.forename: Tomonari
authors.initials: T
authors.lastname: Akamatsu
authors.forename: Satoko
authors.initials: S
authors.lastname: Kimura
mesh_terms: D000162:Acoustics / Q000295:instrumentation; D000818:Animals; D003625:Data Collection; D004784:Environmental Monitoring / Q000295:instrumentation / Q000379:methods*; D005240:Feasibility Studies; D010699:Phonation; D011156:Population Density; D019576:Porpoises / Q000502:physiology*; D045483:Rivers; D012621:Seasons; D012767:Ships; D012815:Signal Processing, Computer-Assisted; D013018:Sound Spectrography; D013997:Time Factors; D014159:Transducers; D014828:Vocalization, Animal