Local corals in healthy conditions with species diversity remain stable: Reef Check

The Reef Check this year showed the local corals are generally healthy, and the species diversity remains on the high side, according to the result announced on Sunday.

The Hong Kong Reef Check 2023, a five-month program started in June, covered 33 survey sites including nine lying within marine parks. A variation in coral coverage - ranging from 12.8 percent to 74.3 percent - was recorded among the sites. 

A Ma Wan of Tung Ping Chau recorded the highest coral coverage, while ten sites recorded over 50 percent of coral coverage. 

Coral bleaching was observed at six survey sites, including Kai Kung Tau of Kat O, Au Yue Tsui of Yau Chau Tong, Wu Pai of Crescent Island, Coral Beach of Hoi Ha Wan and Siu Long Ke. However, the government said the impact was minor and localized. 

It added that the coral bleaching could be caused by the elevated water temperature in the summer.

Moreover, the average health index of the condition of corals at ten designated sites was 4.28, which was slightly better than last year's 4.06. The index is well above the general average value (3), indicating that the corals are generally healthy.

The team determined the corals' health by measuring their color intensity using a specially designed Coral Health Monitoring Chart, and the deeper the color is, the healthier the corals. 

The survey also checked the health status of other indicator species, which included 20 species of fish and invertebrates, and the result showed a high species diversity. 

No signs of destructive fishing practices were observed at any sites, according to the report. Abandoned nets were found at eight sites, but the impact was minor. The Agriculture, Fisheries and Conservation Department will arrange for a contractor to remove the nets.

The Hong Kong Reef Check is part of a global program to promote the sustainable management of coral reefs. It 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. This year, 103 dive teams involving over 1150 volunteer divers participated in the exercise, representing about 30-fold the number in 1997.