The impacts of marine traffic on the Indo-Pacific humpback dolphins (Sousa chinensis) in Hong Kong waters

2014 ◽  
Author(s):  
Ho-yin Chan
Keyword(s):  
Hong Kong ◽  
Marine Traffic ◽  
Sousa Chinensis ◽  
Hong Kong Waters

scholarly journals High-Speed Vessel Noises in West Hong Kong Waters and Their Contributions Relative to Indo-Pacific Humpback Dolphins (Sousa chinensis)

2012 ◽  
Vol 2012 ◽  
pp. 1-11 ◽  
Author(s):  
Paul Q. Sims ◽  
Samuel K. Hung ◽  
Bernd Würsig
Keyword(s):  
Hong Kong ◽  
High Speed ◽  
Ambient Noise ◽  
Sound Pressure ◽  
Behavioral Changes ◽  
Noise Levels ◽  
Acoustic Disturbance ◽  
Sousa Chinensis ◽  
Hong Kong Waters ◽  
Low Traffic

The waters of West Hong Kong are home to a population of Indo-Pacific humpback dolphins (Sousa chinensis) that use a variety of sounds to communicate. This area is also dominated by intense vessel traffic that is believed to be behaviorally and acoustically disruptive to dolphins. While behavioral changes have been documented, acoustic disturbance has yet to be shown. We compared the relative sound contributions of various high-speed vessels to nearby ambient noise and dolphin social sounds. Ambient noise levels were also compared between areas of high and low traffic. We found large differences in sound pressure levels between high traffic and no traffic areas, suggesting that vessels are the main contributors to these discrepancies. Vessel sounds were well within the audible range of dolphins, with sounds from 315–45,000 Hz. Additionally, vessel sounds at distances ≥100 m exceeded those of dolphin sounds at closer distances. Our results reaffirm earlier studies that vessels have large sound contributions to dolphin habitats, and we suspect that they may be inducing masking effects of dolphin sounds at close distances. Further research on dolphin behavior and acoustics in relation to vessels is needed to clarify impacts.

Crassicauda sp. in an Indo-Pacific humpback dolphin (Sousa chinensis)

2020 ◽  
Vol 8 (3) ◽  
pp. e000865
Author(s):  
Nathalie France Mauroo ◽  
Philip S L Beh ◽  
Eileen Harris ◽  
San Y Chan ◽  
David I Gibson
Keyword(s):  
Hong Kong ◽  
Mammary Gland ◽  
South China Sea ◽  
Histological Examination ◽  
South China ◽  
First Record ◽  
Postmortem Examination ◽  
Sousa Chinensis ◽  
New Geographical Record ◽  
Hong Kong Waters

A female Indo-Pacific humpback dolphin (Sousa chinensis) stranded in Hong Kong waters presented on postmortem examination with a single nematode with a diameter of 0.1 cm in the mammary gland, as well as mild multifocal chronic mastitis on histological examination. The parasitic material was recognised as a species of Crassicauda. To our knowledge, this is the first record of a species of Crassicauda occurring in an Indo-Pacific humpback dolphin and also represents a new geographical record for this genus in the South China Sea.

Feeding Habits of Indo-Pacific Humpback Dolphins (Sousa chinensis) Stranded in Hong Kong

2004 ◽  
Vol 30 (1) ◽  
pp. 179-188 ◽  
Author(s):  
Nélio B. Barros ◽  
Thomas A. Jefferson ◽  
E.C.M. Parsons
Keyword(s):  
Hong Kong ◽  
Feeding Habits ◽  
Sousa Chinensis

scholarly journals Distribution of cadmium, chromium, copper, lead and zinc in marine sediments in Hong Kong waters

2007 ◽  
Vol 52 (1) ◽  
pp. 173-173
Author(s):  
S. C. Choi ◽  
Onyx W. H. Wai ◽  
W. H. Lo ◽  
X. D. Li ◽  
C. W. Tsang
Keyword(s):  
Hong Kong ◽  
Marine Sediments ◽  
Lead And Zinc ◽  
Hong Kong Waters ◽  
Copper Lead

scholarly journals Does a Trawl Ban Benefit Commercially Important Decapoda and Stomatopoda in Hong Kong?

Ecosystems ◽  
2020 ◽  
Author(s):  
Lily S. R. Tao ◽  
Gilbert C. S. Lui ◽  
Kingsley J. H. Wong ◽  
Tommy T. Y. Hui ◽  
Yanny K. Y. Mak ◽  
...  
Keyword(s):  
Hong Kong ◽  
Critical Role ◽  
Field Surveys ◽  
Complex Interactions ◽  
Fishing Gears ◽  
Mean Size ◽  
Commercially Important ◽  
Outer Estuary ◽  
Hong Kong Waters

Abstract Crustaceans were among the most valuable fishery resources in Hong Kong. However, the unrestricted and intensive use of different fishing gears, especially bottom trawling, has led to the depletion of commercially important crustaceans in Hong Kong since the 1980s. This study investigated whether commercial crustaceans recovered after the implementation of a permanent Hong Kong-wide trawl ban that began on December 31, 2012. Standardized field surveys were conducted using a commercial shrimp trawler at two sites in eastern and western waters of Hong Kong before (2004) and after the trawl ban (2013–2014 and 2015–2016) and two sites in southern waters after the trawl ban. Diversity, mean size, abundance, biomass and level of disturbance of commercial crustaceans from the three periods were investigated. The eastern waters exhibited an increased diversity of crustacean assemblages in Inner Tolo, and a higher abundance and biomass of crabs were detected in Outer Tolo after the trawl ban. Reduced disturbance, higher diversity in crustacean assemblages and greater abundance and biomass of predatory crabs were observed after the trawl ban in the outer estuary of western waters, and increased abundance and biomass of shrimp were detected in the inner estuary of western waters. No temporal or negative changes were detected in the southeast and southern waters of Lamma Island. The various responses of crustacean assemblages in Hong Kong waters revealed the critical role of complex interactions among multiple stresses, such as ongoing reclamation works, illegal trawling activities and increased fishing efforts using other (legal) fishing methods.

scholarly journals Investigating the spatiotemporal variation of fish choruses to help identify important foraging habitat for Indo-Pacific humpback dolphins, Sousa chinensis

2017 ◽  
Vol 75 (2) ◽  
pp. 510-518 ◽  
Author(s):  
Matthew K Pine ◽  
Ding Wang ◽  
Lindsay Porter ◽  
Kexiong Wang
Keyword(s):  
Hong Kong ◽  
Mainland China ◽  
Spatiotemporal Variability ◽  
Marine Spatial Planning ◽  
Separate Species ◽  
Mainland Chinese ◽  
Predator Prey ◽  
Chinese Waters ◽  
New Information ◽  
Hong Kong Waters

Abstract Given the common physical overlapping between coastal developments and important marine mammal habitats, there is a need to identify potentially important foraging grounds for dolphins when informing marine spatial planning and management of underwater noise. Hydrophones were deployed at four locations either side of the mainland China–Hong Kong Special Administrative Region border to monitor the presence of soniferous fishes; a key prey item for Indo-Pacific humpback dolphins. Five distinct chorus-types were identified; each showing spatiotemporal variability. Each chorus-type was assumed to represent a separate species. Chorus-type diversity also differed between sites, with SP4 and SP5 types only being detected within Hong Kong waters where bottom trawling is illegal. Chorus-type SP1 was only detected at the recording sites in mainland Chinese waters. Call rates and chorus duration were highest during the spring and summer months. Given these dolphins show a predator-prey relationship, these data provide new information on the local fish communities at a much finer-scale than fish landing records and a baseline of fish activity in an environment that is challenging to explore. Overlaid with acoustic detections of foraging dolphins, these data form a basis for identifying potentially important foraging habitats that should be afforded the highest priority for protection.

Macrobenthic communities in Hong Kong waters: Comparison between 2001 and 2012 and potential link to pollution control

2017 ◽  
Vol 124 (2) ◽  
pp. 694-700 ◽  
Author(s):  
Zhi Wang ◽  
Kenneth M.Y. Leung ◽  
Xinzheng Li ◽  
Tong Zhang ◽  
Jian-Wen Qiu
Keyword(s):  
Hong Kong ◽  
Pollution Control ◽  
Macrobenthic Communities ◽  
Potential Link ◽  
Hong Kong Waters
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