INTRODUCTION

Invertebrates are conservatively estimated to comprise about three quarters of all living species. Approximately 1.4 million invertebrates have been described, compared with 0.25 million flowering plants and only 46,000 vertebrates. After insects, mollusks are probably the most family invertebrates. The importance of mollusks in ecological processes and as a living resource of benefit to man should not be under-estimated. Mollusks are major components of food chains, are of primary importance in the cycling of nutrients. The causes of the decline and extinction of molluscan species can be broadly divided into natural events and human activities. The major threat to mollusks throughout the world is the destruction and alteration of the habitats on which they depend. Three other factors recur regularly is pollution, exploitation, and the introduction of exotic species (Wells et al. 1983). In 1973, a positive aspect of CITES listing is that international attention is drawn to species concerned, thus assisting conservation efforts at the national level.

Two kinds of mollusks are listed in the CITES Appendix I﹕Freshwater naiads in North America and Achatinella in Oahu, Hawaii. The mollusks in the CITES Appendix II are the Giant Clams, Green Tree Snail, New Zealand Amber Snail and the Queen Conch. For species to qualify for inclusion in one of the Appendices they should fulfil a strict set of criteria. Nevertheless, it is generally considered that certain species merit inclusion on Appendix II in order to provide means of monitoring international trade in them. Although there are five species of Giant Clams in Taiwan, other mollusks listed in the CITES are also described in this monograph. Each species with Chinese name, common name, diagnosis, distribution, type locality, original description, synonymy, remarks and colour pictures are described in details.