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NATURAL HISTORY

western sector, influenced by the Zhu Jiang (Pearl) River and predominately brackish, and an eastern sector, subject to the influences of the open sea. Various locations provide natural propagation and nursery grounds for many species of fish, crustacea and molluscs, and provide seasonal feeding for large transient predators, such as the Little Tuna, Dolphinfish, Sailfish and sharks. A new publication, Hong Kong Freshwater Fishes by Dr I. J. Hodgkiss (Urban Council series), lists the many species to be found in local streams and reservoirs.

In 1980, a 6.6 metre-long whale shark a species rarely seen in Hong Kong waters – was landed at Aberdeen by a local fisherman. The shark was caught near Pratas Island in the South China Sea. Over the years, more than 20 species of shark have been recorded in Hong Kong waters, mainly in the eastern and south-eastern areas. Sharks have been sighted in Mirs Bay in the New Territories, and as far south as Stanley and Deep Water Bay on Hong Kong Island. Their presence in Hong Kong is a result of the influence of warm ocean currents off the South China Sea during the summer months, in particular, July to September.

Sharks which are common in Hong Kong and potentially dangerous, are the Hammer- head Shark species and the True Shark family species, which can grow to more than three metres. Other commonly-found sharks which do not normally attack humans include the Cat Shark and the Leopard Shark.

Flora

The Hong Kong Herbarium is more than 100 years old. This government institution contains a collection of about 33,600 plant specimens, and is responsible for collecting, classifying and maintaining authoritative preserved plant specimens representative of Hong Kong flora. It also disseminates knowledge and information about the flora of Hong Kong and maintains an index of scientific, Chinese, and English common names for the plants of Hong Kong. The herbarium, located at the headquarters of the Agriculture and Fisheries Department in the Canton Road Government Offices in Kowloon,- is open to the public.

Situated near the northern limit of the distribution of tropical Asian flora, the plants of Hong Kong are large in number and variety. It is estimated that there are about 2,600 species of vascular plants, both native and introduced. These are listed in the Check List of Hong Kong Plants (Agriculture and Fisheries Department).

Before the introduction of conservation measures, the hillsides were becoming increasing- ly bare of trees as a result of cutting, burning and exposure to the elements. On most the only cover was coarse grass or scrub. Now many slopes, particularly those in the water catchment areas, have been planted with trees of both local and exotic species. These woodlands, and other areas of countryside, are protected and are being developed for the growing numbers of people who spend increasing amounts of their leisure time in the countryside.

Remnants of the original forest cover - either scrub forest or well-developed woodlands are still to be found in steep ravines. These have survived the destructive influences of man and fire through their precipitous topography and moist winter microclimate. It is in such places that many of the more interesting plants grow. Small areas of well-grown wood- lands can also be found near the older villages and temples. These fung shui, or sacred, groves owe their existence to the protection afforded by generations of villagers in accord- ance with ancient tradition.