Biology Reference
In-Depth Information
Chapter 18
D
ETECTION OF
Y
ANGTZE
F
INLESS
P
ORPOISES IN
THE
P
OYANG
L
AKE
M
OUTH
A
REA VIA
P
ASSIVE
A
COUSTIC
D
ATA
-L
OGGERS
Songhai Li
1,
Shouyue Dong
1, 2
Satoko Kimura
3,
Tomonari
Akamatsu
4
, Kexiong Wang
1
, and Ding Wang
1
1
Institute of Hydrobiology, Chinese Academy of Sciences,
People's Republic of China
2
Graduate School of Chinese Academy of Sciences, Beijing, China
3
Graduate School of Informatics, Kyoto University, Kyoto, Japan
4
National Research Institute of Fisheries Engineering, Hasaki, Kashima, Ibaraki, Japan
A
BSTRACT
This chapter presents preliminary results on the distribution pattern of Yangtze
finless porpoises (
Neophocaena phocaenoides asiaeorientalis
) in the Poyang Lake mouth
area by using passive acoustic data-loggers at four different stations. Porpoise sounds
were detected at all stations but their abundance decreased as the distance from the
Yantze River increased. Porpoises were detected swimming both upstream to the Poyang
Lake and downstream to the Yangtze River as well as between railway and highway
bridges at the end of the lake. They were detected 13.9% of the total time monitored, and
detected less frequently between 05:00 and 10:00 and between 15:00 and 18:00 during
heavier shipping traffic. Also, there were relatively vacant periods between July 12 and
July 28, 2007, and between August 5 and August 22, 2007, when virtually no porpoises
were detected while there was a reversal of water current or increased water turbulence in
the mouth area. These results suggest that movement and genetic communication
between porpoise groups in the Yangtze River section and Poyang Lake might still
remain, and therefore, the groups should be considered collectively, as a uniform unit for
conservation. Bridge construction, shipping traffic, and current (turbulence and
direction), might have affected the presence or movement pattern of porpoises in the
study area and should be included in future conservation plans.
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