書誌事項
- タイトル別名
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- Monitoring Local Migration of Yangtze Finless Porpoises by Acoustic Gate
- オンキョウ カンソクモン ニ ヨル スナメリ ノ チイキテキ コウドウ カンサツ
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Passive acoustical monitoring systems were used to monitor local migrations of Yangtze finless porpoises in China. We stationed 3 acoustic data loggers (W20-ASII) at 3 different places in the confluence area of Poyang Lake and the Yangtze River on 27-29 April 2006. Acoustic data loggers recorded ultrasonic signals from porpoises swimming in a 300m radius approximate range. Visual observations were conducted simultaneously at two stations. Acoustical and visual observation could detect the presence of porpoises at 73.9 ± 20.9 % and 7.0 ± 6.5 % at all observation times, respectively. Visually-counted group sizes were underestimated compared with acoustical observations for groups of up to 5 individuals, whereas the opposite was true when the group size was more than 6. In summary, a passive acoustical method was proved to be effective for the long term monitoring of finless porpoises swimming underwater. The limitation of group size estimations is thought to be caused by a less accurate measurement of sound source direction due to the short baseline of W20-ASII. It can be improved by employing longer baseline stereo hydrophones.
収録刊行物
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- 海洋音響学会誌
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海洋音響学会誌 34 (4), 260-265, 2007
特定非営利活動法人 海洋音響学会
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詳細情報 詳細情報について
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- CRID
- 1390001204366169472
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- NII論文ID
- 130004490618
- 40015667966
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- NII書誌ID
- AN10299394
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- ISSN
- 18816819
- 09165835
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- NDL書誌ID
- 8972402
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- 本文言語コード
- ja
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- データソース種別
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- JaLC
- NDL
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