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PART I. DESCRIPTION AND SCIENTIFIC SIGNIFICANCE OF THE MAI PO MARSHES
3.
Description and Present Status of the Mai Po Marshes
3.1
The Mai Po Marshes listed under Schedule Four of the Wild Birds and Wild Mammals Protection Ordinance Cap. 170 cover an area of about 940 acres (381 hectares), of which about 515 acres (209 hectares) are kei wais and bunds.
3.2
The hamlet by the Tam Kon Chau Police Host consists of about 47 Temporary structures'. There are about 51 structures in the kei wai area and the total number of occupants for the entire area is about 200- the majority being in the Tam Kon Chau hamlet.
3.3.
There are two points of pedestrian access into the area (Fig. 1); one along the road from Mai Po Village to Tam Kon Chau Police Post and through the hamlet; the other across a wooden bridge at Tai Shang Hai. On the Marshes there are footpaths along most of the bunds which divide the kei wais, though some of these are very rough. At high tide there is access to the outer bund from the sea, but at low tide large areas of mudflat are exposed and access by boat is not possible. There are no roads on the Marshes.
3.4
The two main economic activities of the people living in the arca are working the kei wais and oyster farming. Kei wais are enclosed mudflats below the high tide level, in which the water level is artificially controlled by the use of sluices. They are used to catch scafish and a particular type of shrimp which is much valued in Chinese cuisine, both of which are caught in nets placed at the sluice-gates. A green alga is also harvested for pig feed. In general the centre of each kei wai is a shallow mudflat, sometimes covered by mangrove and other marsh plants, surrounded by a raised bund. Between the bund and the mudflat is a deeper channel of water which ensures a quick runoff from the mudflat when the area is drained.
3.5
The mudflats in the kei wais are one of the most important features of the area, as they provide a feeding ground for considerable numbers of resident and migratory birds. It should be appreciated that the kei wais arc a man-made seral stage in a natural succession pro- gressing from tidal mudflat, through mangrove swamp, wet marshland and reed bed to dry land. Due to geomorphic changes the whole of the Deep Bay area is being uplifted and silt deposition from the Pearl and Sham Chun Rivers compounds the process. Thus it is only the existing positive management regime which prevents the kei wais from silting up and subsequent complete invasion by mangrove, Phragmites etc. If the habitat is to survive it is essential that the existing management regime be continued.
3.6
There are small oysterbeds by the sluices of some of the kei weis, but most the oysters are cultivated on the mudflats to the seaward side of the outer mangrove belt. Access to these oysterbeds is either by foot from the outer bund, through creeks in the mangrove, or by boat.. However, due to the current geomorphic changes, the mangrove community is flourishing and spreading out into Oyster Bed Number Five (Fig. 2), consequently the oyster industry is of decreasing economic importance.