1. BACKGROUND

The participating countries of the South China Sea Fisheries Development and Coordinating Programme (SCSP) (Indonesia, Khmer, Malaysia, Philippines, Singapore, Thailand, United Kingdom for Hong Kong) and Vietnam cover an area of 3 407 300 Km² and have an aggregate population of 247 680 000 growing at an average rate of 2.5 percent per year. The general economic condition in the area can be said to be moderate with an average annual per capita GNP of US$425 ranging from US$80 to US$1200 (ANNEX 1). It will be noted that there is great variation within the region and undoubtedly there could be some far-reaching effects of recent political upheavals in parts of the area.

Food from fishery resources is a major economic feature in the area. The population is essentially a consumer of aquatic products and fish is a major source of protein obtained from natural waters as well as through aquaculture.

1.1 Status of aquaculture in the South China Sea area

Aquaculture is a developed industry in the region and brackish water fish farming is one of the widely practiced aspects of this industry. At present there are on record 881 057 hectares devoted to aquaculture industry with a total production of 538 494 tons. There are still approximately 11 572 700 ha in the South China Sea Sub-region which can be developed for the expansion of this industry (ANNEX 2).

1.2 Scope of subject

The wide development of brackish water aquaculture industry can be attributed to the availability of suitable sites for development and the initiative of the people in the region. In the latter case the engineering aspect of the industry plays a very important role although this has long been neglected or has not been given adequate attention. The scope of this subject, with regard to this industry, are as follows:

1. Brackish water aquaculture project as a physical unit and its relation to the environment in an area

2. Selection of site for development

3. Layout planning, including construction specifications

4. Construction: equipment and procedure

5. Maintenance and operation of a farm project

6. The aquaculture physical unit and its management for production

It will be noted that before the advent of the brackish water aquaculture industry areas of natural mangrove swamps, estuaries and coastal tidal flats were normally in a balanced state or tend to be in balanced state, both physically and biologically. Proper engineering practice requires consideration to preserve this balance of the coastal environment to avoid radical changes such as flooding, depletion of resources, excessive erosion and silting, etc. Selection of aquaculture sites requires consideration of the water supply, soil, vegetation and socio-economic aspects. The layout planning and construction of projects will have to consider the species to be cultured, type of management to be used for production and such physical factors in the site like tides, rainfall, temperature, salinity, etc. Aquaculture engineering should also consider the use or design of equipment or facilities for construction work as well as for maintenance and operation. Overall, the aquaculture unit as a physical unit should be geared to maximize production in a given area.

1.3 Period of study and area covered

This study covered the period from 25 May to 15 August 1975 when the authors travelled extensively in the region to investigate the engineering aspects of the industry (ANNEX 2). Counterpart officials and specialists were met and intervieweed (ANNEX 4). Additional data from previous surveys as well as from published reports were also considered. The countries specifically covered in this study are the following: