Posted July 1996
Because the potential for raising the level of fish supplies from conventional fisheries is fast approaching a practical limit, improvements in production will have to come increasingly through the farming of fish, molluscs, crustaceans and seaweeds. Fisheries output from this source in 1988 was 6.6 million tons in freshwater and 4.7 million tons by mariculture. The total accounted for more than 11 percent of all fisheries production in 1988 and may well double by the end of the century.
Aquaculture production has grown more than 7 percent annually during the 1980s, and has been greatest in species of higher market value. Southeast and south Asia have by far the greatest share of aquaculture production. Many different species are produced. Some are cultured during the complete life cycle whereas others are cultured from wild-harvested seed. Still others are raised in hatcheries and released to open water for later harvesting.
While aquaculture has been practised on a fairly large overall scale in ponds, reservoirs, oceans and seas, it also has a high potential as a component of the production systems of small farmers and hence as a source of cash income for small-farm families. It can be an ecologically sound means of intensifying production in areas of limited available land, salinized or waterlogged soils or low natural fish stocks. Another advantage is that production can be close to centres of population and harvesting can be adjusted to demand so that distribution problems and spoilage losses can be minimized.
The primary scientific and technical constraints to production are the lack of an adequate research base on genetics, reproduction, nutrition and physiology, especially of warm water fishes and the paucity of proven examples of practical, improved culture systems.
Only with a much better understanding of the underlying biological, chemical and physical phenomena can rational improvements in farming procedures be evolved in terms of the ecology of aquaculture production systems. Such systems are complicated as they involve interaction of land, water, fish and a great many groups of associated biota. As yet they are little understood and demand the concentrated efforts of multidisciplinary research. The rewards would be that many kinds of aquaculture can be made more reliable and resilient enterprises than they are today.
The scientific challenges include an understanding of the contribution of naturally occurring feeds, and the dynamics of fish pond systems. Research is needed on the nutritional requirements of the various species under cultivation, as many of the problems with poor growth, disease, and reproduction are proving to be primarily caused by inappropriate management and poor nutrition.
A related need is improved knowledge of the nutritional characteristics and the harmlessness of external feedstuffs available for use in aquaculture systems at economical cost in the different regions of the world. In some areas, considerable dependence is placed on fish meal and comminuted by-catch to provide the feed for aquaculture operations. Since the supply from these sources cannot be increased greatly or readily, research is needed on alternative sources of feed.
Effective genetic selection for improved performance of stocks also depends on our understanding of nutrition and dynamics in aquaculture and on our ability to adapt evolving technologies to given situations. Pond fish farmers are using wild stock of unknown genetic character, and their yields are far below the theoretical limits. Culture-based fisheries in small- to medium-sized irrigation and hydroelectric reservoirs could increase fish supplies if seed fish could be produced more cheaply and harvested more economically and completely. In many regions usage rights to water bodies are poorly defined.
In pond systems which are integrated with land-based farming, the plant and animal wastes from terrestrial activities can be used to increase the fertility and productivity of fish ponds, and sludge from pond bottoms can serve as fertilizers for crops. Care must be taken to avoid pollution that may result from this intensive form of fishery/livestock production.
FAO keeps aquaculture research and development needs under review through COFI and its regional fisheries commissions and committees. Specific activities are carried out under projects, many of them regional or subregional. For example, one of the goals of the FAO programme on Aquaculture for Local Community Development in Southern Africa and of the Bay of Bengal Programme in Asia is to examine in detail the integration of small-scale, part-time aquaculture activities with agriculture from a farming systems viewpoint, and to study social and economic impacts, particularly on women and youth.
In recent years, disease problems have emerged as major constraints particularly in more intensive aquaculture production. Some of these problems are related to environmental conditions and environ-mentally mediated vectors. An FAO study showed that the uncontrolled movement of stocks and species for aquaculture has in the past been a contributing factor to the spread of disease. FAO's European regional body has drawn up a "Code of Practice to Reduce Risks of Adverse Effects Arising from Introductions". This is under examination for adoption by other FAO regional fishery bodies. Too little, however, is yet known about the interrelationships between environmental conditions, the metabolism of farmed organisms and their susceptibility to disease.
Markets for aquaculture products show great variation across the globe. Nevertheless certain minimum requirements in postharvest handling and hygienic conditions are common demands of the trade on behalf of the consumer. The FAO/WHO Food Standards Programme Codex Alimentarius Commission has set standards for several fishery products and is developing one or more codes of good technological/hygienic practice specifically for aquaculture products.
FAO assistance in development of institutional infrastructure for aquaculture has risen continually over the past few decades. In the early 1970s FAO and UNDP set up an Aquaculture Development and Coordination Programme (ADCP). This elaborated the concept of regional aquaculture lead centres. Following the adoption of a strategy in this field by the 1976 FAO Technical Conference on Aquaculture in Kyoto, ADCP developed and strengthened four such centres and linked them in an interregional network. All of the centres have training and research as their mandate. In view of the strength of aquaculture as an industry in Asia, ADCP helped to establish in this region a network of four national centres each of which deals with research and development of different kinds or products of aquaculture for the entire region. Eleven countries of the Asia and the Pacific region recently decided to take full responsibility for aquaculture work in the region under an intergovernmental charter.
At the national level, planning and support for aquaculture development have been assisted by FAO through planning missions investigating what is technically possible, economically feasible and socially acceptable. Some of these missions have been carried out under the FAO/UNDP/ADCP, others under regional projects like that for Latin America (AQUILA).
For proper development of aquaculture, trained staff are essential. Training of aquaculture planners is now a priority in most of the FAO-executed regional programmes. A number of special studies relevant to planning are undertaken by FAO to support this effort. These include the roles of women and youth in aquaculture, the development and application of remote sensing techniques and the Geographical Information System approach to resource assessment and management, coastal zone and mangrove exploitation for aquaculture purposes, and the place of aquaculture in farming systems.
Information is important for proper planning and execution of aquaculture production initiatives, and especially for meeting the opportunities and requirements of markets for aquaculture products. FAO's statistical publications on fishery products are now giving separate information on aquaculture. GLOBEFISH and the associated regional marketing information services also are now receiving more specialized inputs on the aquaculture sector of fisheries the world over and are able to keep users of these services up to date on developments.