•
Species name is Indo-Pacific Humpback dolphin
(Sousa Chinensis), or we call as Chinese White Dolphin
•
First recorded in the Pearl River Estuary by Explorer Peter Mundy
in 1937
•
belong to Kingdom Animalia –Class Mammalia-Order Cetacea- family
Delphinidae
•
At birth - about 100 cm in length
•
Maximum - about 270 cm and 250 kg
•
Up to 40 years old in other parts of the world
•
The oldest in Hong Kong was 33 years old
• Majority of dolphin groups dive less than 1 minute, range from 10 to
277 seconds
• A dolphin group may contain up to 23 members and the mean is 4
• Social structure among them is very fluid and group composition
changes frequently
• Reaching maturity at their age about 10-11,they will get
marry and have their baby.
• Having calves throughout the year, with slight peaks in spring
and summer
•
they love globally, from mid or north of
Australia, South China, Indonesia, India
to South Africa. They live in tropic or
temperate costal regions
• There are roughly 7-8 isolated
populations of Chinese white dolphins
along the coast of China
• In H.K.,they appear in the western
waters,including outer Deep Bay,
north, south and east Lantau, and
west Lamma, but never in the
eastern water
• Their distribution in Hong Kong also shows
seasonal variation
• At least 1400 dolphins found in the Pearl River Estuary and
Hong Kong waters
•
Chinese White Dolphins have 3 different colors which is based on
their age.
oNewborn dolphins are grey in colour
oJuvenile dolphins are pure pink in colour
oAdult dolphins are pink in colour
•
Results from flushing of blood to the body surface
but not from red pigments in the skin
•
Related to thermoregulation
• Dolphins or whales live in deep water regions, but Chinese White
Dolphins live in some shallow water regions
• When they are resting or playing, normally they will assembly in
regions where near to beaches
• Behaviors: breaching, spy-hopping, porpoising, surfacing and
driving
• Chinese White Dolphins have between 116 to 152 tooth
• Dolphins hunt when there is need,, and consume as much as 10 kg of
fish per day, such as lion-head fish (Collichthys lucida), various
croakers (Johnius spp) and anchovies (Thryssa spp) are the
typical types of fish
• One of the most interesting feeding behaviours is that they will
follow fishing trawlers in order to catch those fish that escape from
the nets
• Fishers called the porpoises ‘sea pig’,probably because
they look chubby.
• is another species of marine mammal that lives in Hong Kong waters.
• recognized as relatives of the Chinese White dolphin, but the
differences between the two are quite distinctive.
• Belong in the family Phocoenidae
• They are light grey in colour when
they are young and when they get
older they turn a deep grey.
• Range from northern Japan to the
Persian Gulf, but apparently
excluding most of Philippines
• be found in the adjacent
Chinese waters to the east
and south of Hong Kong
• the Chinese white dolphins and
finless porpoises never occur
together in the same area.
Porpoises
Dolphins
Appearance
Smaller, mostly < 2m
Larger
Dorsal Fin
Smaller
or
even
More triangular in shape
absent Larger, always present
Rostrum or Beak Absent
Prominent
Teeth
Spaded-shaped
Conical
Behaviour
Shy
Very
active
Not
approach
boats Exhibit lots of aerial behaviour,
Not exhibit aerial behaviour
such as breaching, spy hopping,
wake-riding and bow-riding
line transect boat survey
• Two researchers go out on boat look for dolphins along fixed routes
(i.e. transects) in different areas and keep track of the time,
positions and other environmental conditions at the same time
• Record information on group size, perpendicular distance between
the vessel and the dolphins, etc
• Enter data collected from boat surveys into a specialized computer
program called DISTANCE
photo-identification
•
Take photographs on unique features of dolphin's back and
dorsal fin, such as nicks, scars and distinctive colour
patterns
•
Identify each dolphin according to the features, which could
provide information on individual home range and abundance
Square Fin (NL24)
Ringo (NL11)
Curly (NL111)
Slash
(NL139)
General perception that the local population of Chinese White Dolphins
might be extinct in a few years is not true and is not supported by
scientific evidence
Dolphin population in the Pearl River Estuary (including Hong Kong)
contains about 1400 animals. This number indicates the dolphin
population is still viable in the region
•Habitat Loss and Disturbance
•Pollution
•Fishery By-catch
•Vessel traffic
•Depletion of Food Resources
http://www.chinese-white-dolphin.net/game.html
Habitat Loss and Disturbance
• If Construction activities( eg.reclamation ) occurring within the
dolphins’core habitat, then the reclamation would result in a
permanent loss of their habitat.
• For instance, Chek Lap Kok airport platform in North Lantau
• the soil or sand will increase the turbidity. Finally, dolphins no
longer can live in there.
• dolphins might have experienced disturbance and stress
during piling and have temporarily moved out of the adjacent area
during the construction
Pollution
• the sewage could be a potential source of pathogenic bacteria, fungi
and viruses. Chinese White Dolphins are vulnerable to a number of
pathogens which can be transmitted via human sewage wastes.
• other environmental contaminants, such as heavy metals and organic
compounds, can be another potential long-term threat to the local
dolphin population
Fishery By-catch
• Deliberate capture of dolphins does not appear
to be a significant threat in Hong Kong.
• They were however very likely
the result of incidental catches.
• the dolphins will be hurt during
catching by the fish-net
Vessel traffic
• In the photo-identification catalogue, there are some individuals
which show unmistakable evidence of propeller cuts on the body,
apparently resulting from previous encounters with vessel collisions
• vessel traffic also generate noise that can interfere with
communication of dolphins and make the correct decision and action
• vessel collision, together with incidental catch by
fishermen were found to be two of the most significant humanrelated mortality factors.
Depletion of Food Resources
•
feeding habit studies found that there was an overlap in prey of
dolphins and targets of fishing vessels, competition exists between
fishermen and dolphins for the same fisheries resources.
• There is some recent evidence suggesting that the fisheries
resources in Hong Kong have declined. This would affect not
only the fishermen, but also dolphins
• Both of them will surely suffer if the there is a continual decline in
fisheries resources of the area
Aim: to enable the Chinese White Dolphins to continue to use waters
of Hong Kong SAR as a portion of their population range and to
enhance the continued survival of this dolphin population inhabiting
the Pearl River Estuary.
• management
• public education
• research
• cross-boundary co-operation
Management---Improve the General Marine
Environmental Conditions
• Major efforts should be made to clean-up local waters and improve
water quality
• The Strategic Sewage Disposal Scheme (SSDS) is intended to
provide a sewage collection, treatment and disposal system in stages
to improve water quality in Victoria Harbour. (Stage I completion by
late 2001 )
• Government is planning to disinfect all effluent discharging into
North Lantau waters, which is the most important dolphin habitat in
Hong Kong. (disinfection facilities will be provided at Siu Ho Wan
Sewage Treatment Plant by 2004.)
Management--- Minimize or Avoid Impacts
of Coastal Development
• if need to have construction near the habitat of the dolphins,the
proponent would be required to conduct an ecological assessment with
special reference to dolphins.
• to ensure that the residual impact to dolphins would be kept within
acceptable levels.
• the Environmental Impact Assessment (EIA) team established within
Agriculture, Fisheries and Conservation Department (AFCD) would
examine the project to ensure that the impact assessment on
dolphins is properly done
Management---Designate More Marine
Protected Areas
• Statutory designation of the protected core area, followed by its
active and effective management, would go a long way to help
maintain the long-term viability of the species.
• AFCD is considering the way forward with a view to designating
Southwest Lantau as a Marine Park for the benefit of the dolphins.
• During the interim, Southwest Lantau as a Site of Special Scientific
Interest (SSSI).
Management---Ensure Protected Areas
are Properly Managed
• Physical and biological monitoring programmes were established
to keep track of the conditions, both the physical parameters
and biological characteristics within Marine Park.
.• Vessels travelling in the Marine Park must observe a speed
limit of 10 knots
• implementations of measures to re-build the local fish stock will
therefore enhance the long-term availability of prey species to the
dolphins
Public Education ---Promote Community
Involvement and Awareness
• to arouse public interest and awareness of dolphin protection
• AFCD has produced leaflets, posters, Video CD, CD-ROM and
bookmarks on Chinese White Dolphins.
• Exhibition panels have been displayed in some of our
visitor/education centres.
• More information will also be made available
in the AFCD homepage,such that any person
interested may access the information easily
through the Internet
Research---Monitor Trends in Abundance
of Chinese White Dolphins
• Continual monitoring of abundance would provide a useful indicator of
the success of the conservation measures
• The Multi-disciplinary Research Programme on Indo-Pacific Humpback Dolphin Population (MRP) study has provided useful baseline
information for future monitoring
• Collection of stranded dolphin carcasses and detailed
necropsies provide information on the causes of death, and
samples for life history studies
Cross-Boundary Co-operation ---Advisory Body
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The Working Group established in 1995
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Members of the Working Group include scientists, government
representatives, Green Group members, and fishermen leaders
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to seek advice and guidance from Working Group members for
continuous and effective review of the Conservation Programme for
the Chinese White Dolphin
Cross-Boundary Co-operation ---with Neighbouring
Administrations
• A Study Group for the Conservation of Chinese White Dolphin was
established1. in 1997 under the Technical Sub-Group of the Hong
Kong – Guangdong Environmental Protection Liaison Group (EPLG).
• Hong Kong and Xiamen governments to share experience in the
management of protected areas for dolphins and to exchange
knowledge and information on this important species.