Hong Kong Reef Check 2019, a four-month exercise that started in June, covered a wide range of areas including a number of sites of ecological importance as well as the best coral-growing sites known in the eastern part of Hong Kong waters extending from Tung Ping Chau in the north to Ninepin Groups in the south. Among the 33 survey sites, nine were within marine parks, including Hoi Ha Wan, Yan Chau Tong and Tung Ping Chau.
A variation in coral coverage, ranging from 10.0 per cent to 82.5 per cent, was recorded among the survey sites. Fifteen sites recorded over 50 per cent of coral coverage, including five sites within marine parks. Among all sites, Sharp Island North recorded the highest coral coverage of 82.5 per cent.
Reef Check 2019 also assessed the condition of corals at nine sites using the Coral Watch tool. By measuring the colour intensity of the coral using a specially designed Coral Health Monitoring Chart, the health condition of corals can be determined. The deeper the colour, the healthier the corals. The average health index of the sites was 3.96 (ranging from 3.3 to 4.5), which was similar to last year’s figure (4.04). The average health index is well above the general average value (3), indicating that the corals are in a healthy and stable condition.
Hong Kong Reef Check’s survey method and data collection follow international standards. Reef Check divers recorded coral coverage and health status as well as other indicator species (including 20 species of fish and invertebrates). A correlation was observed between coral coverage and species diversity, indicating that sites with high coral coverage tend to support more fauna groups in close association with corals. All of the 20 assigned indicator species were recorded in the survey sites, with wrasses, groupers, butterfly fish, sea urchins, sea cucumbers and cowries commonly found. A majority of the survey sites were found to have a high species diversity. Most of the groupers, wrasses, sweetlips and snappers were found in survey sites at Port Shelter in Sai Kung and North-eastern waters including the three marine parks there.
Coral bleaching was observed at a few sites but the impact was minor and localised.
No signs of destructive fishing practices were observed at any sites. Abandoned nets were found at a few sites but their impact was minor. The AFCD will arrange for a contractor to clear the nets.
Hong Kong Reef Check is part of a global programme to promote the sustainable management of coral reefs. Hong Kong Reef Check aims to raise public awareness of the ecological importance of corals and the need for coral conservation, and to provide updated information on local corals for conservation and management. The Hong Kong Reef Check Foundation held the first Reef Check in 1997. The AFCD has collaborated with the Foundation in conducting the survey since 2000, which has created growing attention and support from the public. This year, 88 dive teams involving over 900 volunteer divers took part in the event representing a 20-fold increase in divers as compared with that in 1997. The AFCD will later present souvenirs and certificates to the Reef Check teams and participating scientists to recognise their contributions.
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