ENG-2007 — Page 336

284 The Environment

The Fisheries Protection Ordinance provides for the regulation of fishing practices. and the prevention of destructive fishing activities such as those involving the use of explosives or toxic substances to catch fish.

Protected Areas

There are 23 country parks and 17 special areas (six of which are located outside country parks) with a total area of 41 644 hectares (about 38 per cent of the total land area of Hong Kong) that are protected areas. They contain scenic hills, woodlands, reservoirs, islands, indented coastlines, marshes and uplands. All are carefully protected for nature conservation, education and scientific studies. Management responsibilities include the protection of woodland and vegetation against fire, control of development, tree planting, litter collection, the provision of educational and recreational facilities, and the promotion of a better understanding of the countryside.

There are four marine parks and one marine reserve covering 2 430 hectares of scenic coastal areas, seascapes and important biological habitats. Marine reserves are dedicated to conservation, education and scientific studies. Fishing in marine parks is controlled through a permit system while such activity is totally banned in marine reserves. Publicity and educational activities are organised for students and members of the public.

Besides designating the abovementioned protected areas, the Government has been identifying and conserving sites of special scientific interest (SSSI), such as areas with special geological features and natural habitats of rare plants or animals, by exercising strict land use planning and development controls. There are 66 sites listed in the SSSI register.

Topography and Geology

Hong Kong's natural terrain is characterised by rugged uplands flanked by steep slopes. The highest point is Tai Mo Shan (957 metres above Principal Datum) in the central New Territories, and the lowest point (66 metres below Principal Datum) is in Lo Chau Mun (the Beaufort Channel) to the north of Po Toi Island. The mountains are predominantly formed of volcanic rocks, whereas the lower hills are mainly formed of granite. Low-lying areas are generally underlain by granite or sedimentary rocks. A layer of soft, weathered rock covers the bedrock in most places, slope debris covers the natural hillsides, while alluvium fills many of the valleys. Offshore, the seabed is covered by marine mud, with sand sheets occurring near the coast and in channels.

The oldest exposed rocks in Hong Kong are composed of Devonian river sediments that were deposited approximately 400 million years ago. The region was subsequently inundated by a shallow sea, which deposited Carboniferous limestones, the parent material of the Yuen Long and Ma On Shan marble. Between 170 and 140 million years ago, during the Jurassic and Cretaceous periods, Hong Kong was the scene of violent volcanic activity that deposited thick accumulations of ash and lava. These eruptions were associated with the development of several calderas (giant craters). At deeper levels, molten magma intruded and slowly crystallised to form