THE PACIFIC OYSTER INDUSTRY IN HONG KONG (的蠔業)
BRIAN MORTON* AND P. S. WONG†
Oyster farming is an ancient industry. The Japanese and Romans are the earliest known oyster farmers, and with time the practice has spread to other parts of the globe. Thus different species of oysters are cultivated in Europe (Ostrea edulis and Crassostrea angulata), North America (Ostrea lurida and Crassostrea virginica), Australia (Crassostrea commercialis), and in Japan and China (Crassostrea gigas—the Pacific oyster). The diverse sites of culture have led to different methods of farming and the utilisation of a range of implements. With research and development, however, the Japanese method of hanging strings of oysters from rafts in the surface waters of the sea is slowly becoming universally accepted as one of the more successful techniques—but traditions die hard.
Oysters (*) have been cultivated in Hong Kong for some considerable time; Bromhall (1958) estimates 700 years though Mok (1973), more conservatively, estimates 170 years. The method of culture is unusual, involving implements of unique design, not hitherto described. The identity of the local oyster remains a mystery though Bromhall introduced the Pacific oyster Crassostrea gigas (Thunberg 1793) (✯✯) into Hong Kong in 1950. It would seem probable, however, that this is also the endemic species, since Hong Kong is within the natural geographic range of C. gigas (Tschang et al, 1962) and specimens have been recovered from archaeological digs on Lamma Island and, more recently, from the mud excavated from the High Island reservoir site.
Oysters only grow in estuaries and the Hong Kong oyster industry is centred around Deep Bay (*) which is situated on the northwestern corner of Hong Kong, forming the boundary between China and Hong Kong (Fig. 1). The bay covers an area of approximately 112 km2 bordered to the landward by a characteristic fringe of dwarf mangroves. Deep Bay opens to the southwest directly into the mouth of the Pearl River (#) which is the major river draining the hinterland of southern China. Numerous rivers and streams
* Department of Zoology, The University of Hong Kong.
† Department of Zoology, The University of Auckland, New Zealand.