Vertebrates

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	New reef fish from High Island dam dollos
	The humphead wrasse: a threatened species
	Reproductive biology of Halichoeres nigrescens, the bubblefin wrasse
	What is SCRFA?
	Starling Inlet - tomorrow's empty wetland?
	The 2002 Woodland Breeding Bird Survey - result highlights
	Nesting population of egrets and herons in 2002-preliminary results
	Is the Yellow-throated Marten in Hong Kong?
	More tiger talk

New reef fish from High Island dam dollosn

by Keith Wilson
Agriculture, Fisheries and Conservation Department
wilsonhk@hk.super.net

At the High Island Dam, just south of Long Ke Wan, a very rich coral and associated fish community has developed on the mass concrete structures (dollos). These structures were placed in front of the dam in 1974 to protect it from rough seas. The dollos form a 0.5 km stretch of artificial reef rising from over 12 metres depth to the sea’s surface. After five years, in 1979, according to P.J. B. Scott’s book on the Corals of Hong Kong, published in 1984, six species of hard coral had begun to colonise the dollos. Today, a rich and extensive coral community has developed with many encrusting corals, including numerous table corals (Acropora solitaryensis) with some measuring up to 1 metre in diameter. A few hermatypic corals even occur at depths below 10 metres, which is unusual for Hong Kong’s turbid waters. A recent fish SCUBA survey, conducted on August 14 2002, encountered 70 fish species at the dollos including several species known to associate with hard coral reefs such as the butterflyfish Chaetodon octofasciatus. Two species, the Blackfin dartfish (Ptereleotris evides) and the Pearlscale angelfish (Centropyge vrolikii) were newly recorded for Hong Kong. Several small shoals of juveniles of Ptereleotris evides were observed and at least three separate individuals of adult Centropyge vroliki. The High Island Dam dollos, form an artificial reef with a high level of complexity, which has been established in shallow waters for over 28 years. It is here that Hong Kong’s most diverse artificial reef fish communities can be found. Few local natural reefs including coral reefs can rival the diversity of fish found at the High Island Dam dollos. A one-year consultancy study has recently been awarded to assess the marine biodiversity of the marine area east of High Island Dam, including the dollos, in consideration of this location as a potential Marine Park.