The need for a paradigm shift in Asian aquaculture
By Dr. M. Shariff & F.M. Yusoff, Faculty of Veterinary Medicine
University Putra, 43400 Serdang, Selangor, Malaysia

Abstract

Asian Aquaculture has gone through immense changes in growth and technology developments during the last three decades. A variety of fish, mollusk and crustacean species are being cultured in many different systems such as cages, ponds, tanks, rafts, pen, and raceways, located in different environments; rivers, reservoirs, mudflats, estuaries and bays. Production has increased manyfold to satisfy the demand at home and abroad as the marine fisheries catches dwindled due to over-exploitation and pollution. Despite the advances in technology, an analysis of the aquaculture production per unit area reveals that yields are not increasing in tandem with the expansion of the industry. The decrease in production in many cases is due to unsustainable aquaculture practices. However, many agencies in the Asian region have given attractive incentives to accelerate the aquaculture industry, resulting in rapid development at the expense of the environment. Since the mid-80's the aquaculture industry in the Asian region has been plagued with serious disease problems resulting in severe losses.

Water has been used extensively in aquaculture activities, resulting in reduced mangrove forests, eutrophicated rivers and coastal waters, and salt water intrusion. The lack of sustainable aquaculture practices has already created a negative impact on the industry. The unsustainable approach for optimization of water resource utilization will eventually result in water as a limiting factor in commercial fish production. There is a need for a drastic change in paradigm to shift to sustainable aquaculture practices using newer technologies that will optimize the use of water. One approach would be to integrate the aquaculture system with other agriculture based industries. Aquaponics, which integrates hydroponics with aquaculture, is a good example of a successful integration. The integration of fish and plants increases diversity and thereby enhances system stability. The principle of the integrated system is to optimize the utilization of nutrients derived from aquaculture for agriculture use. Hence, nitrogen, phosphorus and other nutrients in aquaculture effluent could be effectively removed and utilized by plants of commercial value. However, further studies are necessary concerning the carrying capacity of cage aquaculture, and integrated farming with livestock should be further investigated to reduce pollution and conflicts in the use of water.

Newer technologies could also be considered for incorporation of integrated systems adopting traditional practices such as rice fish culture. Rice cum fish culture is not practised extensively due to shallow waters, use of chemicals such as pesticides and the additional manpower input. If newer technologies could be adapted to overcome these constraints, a vast potential exists in the integration of fish culture and the acreage of large rice fields. Several other examples of integration to turn the aquaculture industry around to a more positive outlook should be studied and implemented.

Another concept of sustainable aquaculture practice would be to use environmental friendly recycling technology with near zero discharge. Such systems have already proved to work well in the developed countries though they would require major technology transfer for adaptation in the Asian region. The major constraint would be the adaptability of such new technologies to tropical conditions to suit the local cultured species. Pilot projects require substantial research and development (R&D) input. Thus, the financial implications of adapting and testing the new technologies involving high capital cost need to be addressed. Successful pilot scale testing would be useful to convince the entrepreneurs to adapt the technology for the promotion of sustainable aquaculture. In addition, the development of a strong consortium between different sectors is necessary to ensure the sustainable use of limited resources.