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Hong Kong Reef Check 2006
Results
Coral coverage
Species diversity
Other observations
Coral Watch
Change in coral coverage (2005 & 2006)
Measures taken by AFCD on coral conservation
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Coral coverage
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Out of the 33 sites surveyed, 21 of them recorded high coral coverage (i.e. >=50%). These sites included A Ma Wan, A Ye Wan and Wong Ye Kowk of Tung Ping Chau, Kai Kung Tau of Kat O, Lai Chi Wo, Au Yue Tsui, Wu Pai, South and West Crescent Island, Tung Wan, Wong Chuk Kok Hoi, Port Island, Coral Beach, Gruff Head and the Public Pier of Hoi Ha Wan, Long Ke Wan, Tai She Wan, Shelter Island, East and North of Sharp Island and Bluff Island.
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Coral Beach at Hoi Ha Wan Marine Park is the site with the highest coral coverage (73.1%)
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Survey sites within Marine Parks (i.e. Hoi Ha Wan, Yan Chau Tong and Tung Ping Chau Marine Parks) recorded high coral coverage (i.e. >50%)
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Out of the 33 sites surveyed, corals at 15 sites were identified up to genus level by the team scientists. This reflects the increased interest of team members on coral identification and the success of the technical training we offered.
Species diversity
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Sites with high coral coverage recorded high diversity and abundance of fish fauna.
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19 out of the total 20 pre-determined indicator species were recorded in the survey. High diversity of indicator species was recorded in most of the sites.
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Out of the 19 indicator species, wrasses, groupers, butterfly fish, sea urchins, sea cucumbers and cowries are common species found.
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Most of the groupers, sweetlips, snappers and wrasses were found in survey sites at Port Shelter and North-eastern waters including the three Marine Parks. Coral trouts were also recorded in some of these sites.
Other observations
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Corals at all 33 sites were in general healthy condition.
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No signs of destructive fishing practices were observed at all sites. However, we have recorded abandoned nets and some coral damages at about 7 sites. The impacts were minor.
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Coral bleaching was also observed at 5 sites. It may be caused by the extended period of elevated water temperature during this summer. The impacts were however localised.
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The coral condition at Bluff Island was markedly improved. The dive team did not record any noticeable and recent coral damages caused by boat anchor. There has been a progressive improvement in coral cover at Bluff Island (from 53.1% in 2002, to 62.5% in 2006) since the installation of marker buoys in this area in 2002. This may have been related to the success of coral marker buoys and continued effort in education and publicity on coral conservation.
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Marker buoys were installed at Ung Kong Wan, Port Island and Sharp Island since 2002 for coral protection. This year, the dive teams recorded an increase in coral cover and a decrease in coral damage in these 3 sites as compared with last year. This may have been related to the success of coral marker buoys and continued effort in education and publicity on coral conservation.
Coral Watch
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The health condition of corals was assessed using specially designed Coral Health Monitoring Chart. The colour intensity of corals reflects the amount of the symbiotic algae (zooxanthellae) inside the corals, which in turn indicates the health status of the corals. The deeper the colour, the healthier is the corals.
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The Coral Health Monitoring Chart has four sample colours and 6 degrees of darkness (Code 1 to 6) for each sample colour representing different stage of coral health condition. Code 1 is the lightest (representing bleaching) and Code 6 has the darkest colour (representing health condition).
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Corals at 24 sites were assessed using Coral Watch. The average index ranged from 3.43 to 5.18, indicating corals were in general healthy condition. Results of Coral Watch are summarized in the graph below.
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Change in coral coverage (2005 & 2006)
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Sites of high coral cover and surveyed by the same dive teams in the past 2 years were selected for comparison. 10 sites were selected.
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The growth and condition of corals at all sites are stable with some sites showing slight improvement. The change of coral cover at these sites is shown in the graph below.
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Measures taken by AFCD on coral conservation
Coral reefs are highly productive systems, which support a high diversity of marine life. AFCD has put in place a series of measures and programmes to protect and conserve the coral communities in Hong Kong. Key areas include:
- Designation of marine protected areas
We have designated four Marine Parks and one Marine Reserve for the conservation of marine environment and protection of corals.
- Education and publicity
We have organized a range of educational and publicity activities including public lectures, seminars and exhibitions to enhance public understanding of the importance of protecting the marine environment and coral communities. We have also published leaflets and booklets to introduce our attractive and diverse coral fauna and educate the public on the need of protecting them. New bookmarks and poster on “Hard Corals of Hong Kong” have recently been published.
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| New Bookmarks |
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| New Bookmarks |
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| New Poster |
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This year, the Department, in collaboration with the Hong Kong Underwater Association and Ocean Park Hong Kong, organized a photo and video competition with a view to promoting the beauty and diversity of coastal and marine environment and enhancing public's understanding and the importance of marine conservation. A Prize Presentation Ceremony was held at Ocean Park on 13 January 2007. The award-winning entries will be displayed in a roving photo exhibition scheduled in mid 2007. We will also produce booklets and CDs of all the winning entries for education and publicity purposes.
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- Monitoring and studies
We actively monitor the status of coral communities of Hong Kong through the annual "Reef Check"activity. There has been an increase in the number of participants and survey sites every year, indicating a support from the public on this activity. Results of the Reef Check are publicised to raise public awareness of the current status of our marine environment and to seek their cooperation in protecting our precious marine resources. Please visit here for details of the Reef Check activity.
In addition to Reef Check, we also undertake comprehensive coral studies to provide information for sound and adaptive management.
- Reduce coral damage caused by boating and recreational activities
To protect coral communities from anchor damage, mooring and marker buoys have been installed in Marine Parks where recreation pressure is high. We have also established “Inboard Vessel Prohibition Zone” at Heung Lo Kok in 2004 restricting the entry of large vessel into shallow areas with corals. This coupled with the existing “Mechanized Vessels Prohibited Zones” would help protecting corals within Hoi Ha Wan Marine Park.
Specially-designed marker buoys were installed at Sharp Island and Port Island and Ung Kong Wan for better protection of coral from anchor damages. In addition to annual Reef Check, regular sea patrols and underwater ecological surveys were conducted to monitor the effectiveness of coral marker buoys in the above areas. The outcome was encouraging. There has been an overall increase in live coral cover in the marker area and damaged corals had shown signs of recovery.
Leaflets and posters on "No-anchoring area" at Ung Kong Wan, Port Island and Sharp Island and stickers on "Codes for visiting coral areas" have been published and distributed to the boaters and divers through various channels.
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| Marker Buoys |
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| Leaflet and poster for Ung Kong Wan |
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| Leaflet and poster for Port Island |
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| Leaflet and poster for Sharp Island |
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| Codes for visiting coral areas |
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| Codes for visiting coral areas |
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| Codes for visiting coral areas |
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- Scientific database
We have completed a study to verify and update all hard coral species recorded in our local waters. A total of 84 hard coral species, from 28 genera of 12 families were confirmed. A coral field guide showing 20 hard coral species commonly found in Marine Parks has been uploaded to the departmental website. A reference collection containing a complete set of all 84 hard coral specimens has also been set up for public education and exhibition. We have also published the “Field Guide to Hard Corals of Hong Kong” in July 2005 to document the diversity and unique features of local corals.
To extend our knowledge on the distribution and diversity of other coral fauna in Hong Kong, we have commissioned the Chinese Unversity of Hong Kong to undertake a study to update the inventory records of octocorals and black corals within Hong Kong waters. Study findings would be useful for conservation and management purposes.
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