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area of about 115 km2 and contains 330 Mm3 of water at mean sea level (about 1.3 m above Hong Kong principal datum (PD)). Sand is brought into Deep Bay close to Black Point on the flood current and moved along the Hong Kong coast by wave action during storms. Silts and clays appear to be largely derived from the catchment draining to the inner part of Deep Bay.
The tides are complex, with a strong diurnal component superimposed on a semi-diurnal pattern. The usual sequence is thus two high waters and two low waters in just over 24 hours, with one high and one low significantly higher or lower respectively than the other. On certain occasions (14 in 1984) the diurnal component completely dominates and only one high and one low occur in a day. The maximum tidal range is about 2.8 m.
Historical background
Oyster cultivation is traditional and has been practised in the Pearl River estuary for several hundred years. The coastal town of Shajing (JP) has long been associated with oyster fattening. Oyster cultivation has been practised in Deep Bay since at least 1800 (Bromhall, 1958; Mok, 1973).
Disputes over the ownership of Deep Bay oyster beds led to short term leases being granted in 1909 to those organisations, both those based in Hong Kong and those based in China, who could prove good claim to ownership prior to 1898 when the Crown Lease of the New Territories commenced. One oyster bed was reclaimed from the sea around 1915/16 and now forms part of the Tin Shui Wai area. Additional oyster beds were leased, mainly in the mouth of the Shenzhen River, during the period 1909 to 1933. The original 1909 leases were extended from 1931 to 1952.
During the early part of World War II many oyster farmers with much traditional expertise moved from Shajing to settle in the Lau Fau Shan area, but the majority of the beds were either ruined or fell into disuse by 1945. Reorganisation of the industry in the immediately post-war era was influenced by events within China culminating with the establishment of the People's Republic of China in 1949. Further leases were granted to some oyster farmers