Michael J. Phillips1
ODA Seconded Associate Professor
Division of Agricultural and Food Engineering
Asian Institute of Technology
PO Box 2754
The presentation of Dr Michael Phillips was concerned with the environmental management of aquaculture in Asia - particularly actions to be taken at the farm level. The talk concentrated on the concepts of environmental management, rather than a detailed discussion of the problems or the particular management methods applied. Details of the different environmental issues and various management strategies applied are given in the country reports. The presentation also emphasised the common nature of many of the environmental issues arising throughout the region.
A. Aquaculture is part of the natural environment
The development of aquaculture relies on natural resources, and therefore development is heavily dependent on the quality and quantity of available resources. The major resources required include:
Land: required for siting of farms and associated infrastructure;
Water: obviously, essential for aquaculture, both in terms of the quality and quantity available;
Feed: required to ensure nutrition of the cultured crop and includes: nutrients (e.g. seaweed); primary productivity (e.g. mollusc); secondary productivity (e.g. carnivorous and/or omnivorous shrimp and finfish).
Seed: required for stocking of culture systems, and may be obtained either from capture fisheries, or culture fisheries.
As these resources are often in use or required by others the potential for conflict arises, particularly when there is a shortage in relation to human pressures (e.g. when population pressures are high). Thus, because aquaculture utilises natural resources which other people may use:
It is highly dependant on the quality and quantity of resource (e.g. water pollution, soil characteristics, high quality seed and feed)
There is potential for conflicts over access to resources (particularly when resource use is intense, e.g. high population pressures, large culture areas)
Therefore, what may be considered “ideal” environmental management of aquaculture should give consideration both to:
on-farm (internal) management of resources (e.g. in maintaining suitable conditions for the culture stock, and reduction of environmental impacts); and
off-farm (external) management of resources;
1 Present Address: NACA, P.O. Box 1040, Kasetsart Post Office, Bangkok 10903.
In other words, the environmental management of aquaculture should consider aquaculture as part of the whole resource system upon which it relies. It could also be suggested that environmental management of aquaculture should involve other resource users, because aquaculture may affect both the quality and quantity of resources -- such as water and land -- which are required by other members of the community, i.e. aquaculture is often using “common” resources.
B. Environmental impacts of aquaculture
The environmental impacts of aquaculture can be considered as positive, neutral or negative.
Neutral environmental impacts:
Virtually all aquaculture systems are -- by their nature -- reliant on some external inputs of natural resources and as such, there are few aquaculture systems that can be regarded as having a totally “neutral” impact on the environment. Small-scale, integrated aquaculture-agriculture systems, where pond inputs are coming from within the agricultural farming system, may fall into this category. The farmer will still, however, have to consider alternatives at farm level for the “best” (most economic?) use of land, water, feed and seed. The scale of environmental impacts from many small-scale culture systems are small -- particularly when integrated into existing agricultural systems -- making the environmental impacts close to neutral.
Positive environmental impacts:
There are many good examples of positive impacts of aquaculture on the environment, such as environmental impacts:
on aquaculture (e.g. where water made eutrophic by discharge of domestic wastes, provides good opportunities for aquaculture, as in some sewage fed fish ponds, or in the case of seaweed culture in NE China, where hypernutrification of coastal waters in recent years has reduced the need to fertilise culture areas); and
of aquaculture (e.g. wetlands in Hong Kong, where fish ponds near Mai Po marshes help protect the wetland environment from encroachment by urban and domestic development; sewage fish culture, where potentially pollution wastes are recycled through fish ponds; and the “cleaning” of eutrophic reservoirs by filter feeding Chinese carps).
In Chapter 18 of AGENDA 21 -- the output from the United Nations Conference on Environment and Development -- the potentially beneficial role of freshwater fisheries and aquaculture in protecting freshwater resources is recognised, although mention is made in Chapter 18 that such activities should not contribute to environmental deterioration.
Negative environmental impacts:
There are a number of negative environmental impacts to consider, such as environmental impacts:
on aquaculture (e.g. degradation of land resources through siltation; reduction in the quantity of water available; degradation in the quality of water resources for aquaculture, through water pollution, red tides, water resource developments). The magnitude of the problems are undoubtedly serious for aquaculturists. For example, the estimated regional losses from red tides over the past few years are in excess of US $ 100 million.
of aquaculture. The effects of aquaculture on the environment cover a range of different impacts. These include impacts on:
In most instances, it appears that the magnitude of the problems is not well understood. The instances where data on magnitude does exist, mostly comes from cases where aquaculturists have been adversely affected.
of aquaculture on aquaculture. This issue refers to the effects of aquaculture operations on itself, e.g. self-pollution. The most common issues raised are related to water quality, which appears to be a major issue in some culture areas, e.g. effluent discharge leading to increased nutrients, organic loads and pathogens in culture areas. The problem is most acute with shrimp culture and cage culture.
The magnitude of the problems are not well documented, but there are several examples in intensive aquaculture, particularly shrimp culture, where economic losses to aquaculturists (as a group) have been in excess of several 10s of US $ millions -- and in some notable examples, in excess of US $ 100 million.
C. Factors affecting environmental impact
There are several factors which affect the potential for environmental impacts to occur. These are considered below as.
Type of aquaculture system
The type of aquaculture system is important, particularly it's “openness”, i.e. the extent to which the culture system relies on external (off-farm) inputs, and the extent to which the sitting of the aquaculture farm exposes it to environmental change. In general terms:
Greater openness implies greater environmental interaction, e.g. seaweed and mollusc farms are vulnerable to environmental change, intensive farms relying heavily on external inputs (and where waste materials are not recycled) have greater potential for environmental impact.
Closed systems, involving recycling of water, organic matter and nutrients, with the aquaculture system, or where aquaculture is part of a large agricultural system, are likely to give rise to less environmental impacts, and be less vulnerable to environmental changes taking place outside of the farm.
In more open systems, more attention should be given to environmental management, particularly in relation to the “external” environment.
Degree of intensification
An important issue is the degree of intensification. This can be seen at two levels:
The culture system, e.g. with increasingly intensive use of inputs (of water, feed, seed), the potential for environmental impacts increases, particularly related to effluents. Disease problems become serious and the need for disease control and water quality management becomes more important Experience has shown that each culture unit has a finite capacity for development (e.g. pond, tank or culture area).
The aquaculture environment. It is becoming increasingly clear that each aquaculture environment also has a finite capacity for development, which seems to be clear for all species. Examples exists for seaweed culture, mollusc culture, finfish cage culture and shrimp culture where environmental impacts have arisen because the “intensity of resource use” by aquaculture has exceeded the capacity of the environment, either to supply feed (e.g. nutrients and particulate matter for seaweed and molluscs) or to flush waste materials away from culture sites (e.g. cage culture and shrimp culture areas in several countries in Asia). The effects of exceeding the “environmental capacity” can be potentially serious. The environmental capacity for aquaculture will also depend on the intensity of resource use, such as water and land, by competing sectors - which will also affect the level of acceptable environmental change. That is, the capacity for aquaculture development will be less if there are many other competing users of land or water, or the environment is viewed by society as a whole as being of particular value.
The biological characteristics of the culture species are important, particularly in relation to:
Location of aquaculture facilities
The location of the aquaculture facilities will also play an important part in determining environmental impact, particularly in relation to existing patterns of land and water use, in terms of current “value” of existing resources, and their human social and economic use/potential).
Operation of aquaculture facilities
The operational practices of aquaculture farms also plays an important role in environmental impact, particularly water, soil, seed and feed management. Farms operating similar culture systems, in similar environments may have different environmental impacts through differences in the operational management of their resources.
There are several examples where concerns have arisen over the actual and potential impact of introductions of new species, or of transfers of species within the range. The issues relate to the culture of all the main commodity groups and culture systems. The main concerns are:
Loss of indigenous species due to harmful side effects of the new species, either through competition with indigenous stocks, or introduction of new parasites or pathogens.
Reduction in the productivity or diversity of indigenous stocks, for similar reasons.
Examples can be found in the region where introductions of new species have been beneficial, e.g. clams in China, which are now responsible for a highly significant industry. There are other examples where pathogens have been spread through the region by the unregulated movement of aquatic species, examples been seen with the spread of MBV (monodon bacilovirus) in shrimp culture areas. Concerns arise because there appears to be a lack of understanding of environmental impacts and a lack of effective measures to control impacts, although various international protocols for restricting adverse impacts exist.
D. Environmental management possibilities
The environmental management possibilities that exist, are found at two levels:
The private sector
The private sector includes farmers and supporting industries. Within this sector, environmental management may be implemented:
at farm level, particularly in relation to the location and management of individual farms.
through farmer groups/co-operative actions. Co-operative action may be required where farmers are sharing common resources. Increasingly, examples can be found in shrimp culture where farmers are co-operating to solve common problems, e.g. in controlling water pollution through co-operative water management.
In addition to the problems mentioned above, there are some increasingly serious and emerging incentives for improved environmental management within the private sector, particularly where farmers are growing crops, e.g. shrimp, for export markets. These “incentives” include:
Non-tariff barriers. The possibility of trade barriers being erected because of environmental concerns. For example, there are reports in the region where pressure groups within importing countries have tried to implement bans on shrimp products from Asian countries, because of concerns that shrimp culture was contributing to mangrove destruction. The possibility for increasing use of non-tariff barriers exists.
Market acceptability. The market acceptability of a product will clearly be affected by the consumers image of the product. If there is unacceptable contamination with antibiotics (e.g. as reported occasionally with shrimp) or other materials (e.g. public health concerns related to molluscs) (real or imaginary), then this will affect the marketability and profitability of aquaculture enterprises. As water pollution problems increase, and as consumer awareness over “clean” or “organic” foods increases, aquaculture production will need to give increasing attention to culture environments.
Economic losses from disease. The growing economic losses to farmers - seen particularly in shrimp culture - many of which are related to some form of environmental deterioration, provides a strong incentive to improve the environmental management of farms. Where environmental problems arise from outside of the farm, e.g. through self-pollution of culture areas, then these problems provide incentives for farmers to co-operate, or seek assistance from governments in confronting problems.
The public sector
Within the public sector, various “supportive” actions may be possible. These actions are considered in other presentations - the legal and other sections. Below some of the private sector options are discussed.
E. Private (farm) sector management options
The following details some of the farm management options which may be considered in improving the environmental management of aquaculture.
Aquaculture system potentials:
As “open” systems are more “vulnerable” to environmental problems, there are possibilities to reduce environmental impacts, by moving towards more closed systems. Closed systems are usually less vulnerable to many of the environmental impacts on aquaculture, and environmental impacts of aquaculture may sometimes be reduced by reliance on less external inputs and recycling of potentially damaging materials (e.g. pond effluent) within the farming system. Examples are:
in small-scale integrated aquaculture-agriculture farming systems, where potentially polluting materials are recycled within the farming system;
through promotion of polyculture and integrated forms of culture, in inland and coastal aquaculture, involving recycling of nutrients and organic matter. Considerable scope exists for such systems in marine environments, where much monoculture occurs;
on-farm recycling of water, as seen in recent trends in the shrimp culture industry (mainly to reduce related to introduction of shrimp pathogens into farms).
The biology of the culture species is also an important aspect. The selection of species which are well adapted to the culture environments is important, e.g. water polluted with organic discharges will be less suitable for mollusc culture than fish. Alternatively, some species have a higher tolerance to poor environmental conditions than others. There may also be some merit in promoting the use of indigenous fish species, rather than relying on exotic species, which have potential for negative impacts on both indigenous culture and capture fisheries.
Degree of intensification - environmental capacity
The degree of intensification of any aquaculture system plays an important role in environmental impact. In terms of management, consideration of two aspects are important:
Intensification within the aquaculture system, e.g. ensuring culture intensity, in terms of stocking, production and feeding, is matched to the capacity of the culture system. Obviously, effluent problems are normally less serious in semi-intensive culture than in intensive culture; and
Aquaculture environments. In practical terms, this means that the culture intensity is matched to the environmental capacity. Practical examples where such management has been applied include the environmental management of oysters in the Republic of Korea and finfish cage culture in Hong Kong. Unfortunately, there are many examples where such considerations have not been taken, particularly in the shrimp culture industry.
Having recognised that environmental capacity is important, at the aquaculture system and aquaculture environment level, there may be opportunities to enhance the environmental capacity through improved management. Examples may be: (i) improving the water supply and drainage systems in shrimp culture areas; (ii) reducing the feeding rates in intensive aquaculture to enhance the capacity of ponds; and (iii) reducing the stocking density in mollusc culture areas (as seen in the Republic of Korea).
Location, design and operation
Clearly the location, design characteristics and operational features of aquaculture systems all play an important role in environmental impact.
i. For land resources:
Among the important considerations are: (i) the use of lower value land resources for aquaculture (e.g. non-mangroves, non-agricultural land). Choices related to land use will depend to some extent on the “values” assigned to different land types by society; and (ii) consideration of the siting of farms in relation to other users, both in terms of the environmental impact on aquaculture (e.g. siltation) and possible conflicts with other users.
ii. For water resources:
The considerations are: (i) as above, consideration of the siting of farms in relation to other users, both in terms of the environmental impact on aquaculture (e.g. water pollution) and possible conflicts with other users, e.g. through effluent discharge, water use conflicts; and (ii) design of water supplies and drainage systems, to avoid self-pollution problems, as well as conflicts, e.g. proper design of drainage systems to avoid salinisation of freshwater by coastal shrimp ponds.
In practical terms, both require the proper identification and consideration of potential environmental problems during site selection. An alternative is to zone aquaculture enterprises (with consideration of environmental capacity), a management technique which can reduce conflicts between different users, by concentrating aquaculture in selected areas. Examples are to be found in the Republic of Korea and Hong Kong.
iii. For feed (and fertiliser) resources:
Among the important environmental considerations are: (i) diet type (wet, moist, dry pellet); (ii) source of feed; (iii) feeding intensity and method; and (iv) alternative uses of the feed or fertiliser, both on and off-farm.
iv. For seed resources:
Among the important considerations are: (i) the origin of stocks (e.g. wild or hatchery); and (ii) pathogen/disease status of stocks.
F. Environmental management through co-operative action
The above notes provide some information concerning environmental management possibilities at the individual farm management level, mainly in terms of the siting and operation of aquaculture farms. However, as farmers may often share resources with other aquaculture farmers, and non-aquaculturists, only so much can be done at the farm level. Effective management of shared resources (e.g. water) requires sharing in the responsibilities for management. Thus, individual actions by farmers are unlikely to be sufficient where farmers are using common (or public) resources, i.e. co-operative management is required.
There are several examples of co-operative action by aquaculture farmers which can be seen around the region. For example, there is a growing tendency for shrimp farmers to share water management responsibilities. This co-operation is in response to a realisation among farmers that individual actions are not enough to control the problems associated with polluted water supplies - examples are seen in Thailand and Indonesia.
Whilst such co-operation is possible and desirable, co-operative or individual actions among farmers may not be enough. As many environmental problems arise outside the sector, solutions to some of the problems require actions outside of the sector. Thus, co-operation between aquaculturists and non-aquaculturists may be necessary, particularly where there are many “users” for a limited resource, i.e. some form of integrated management may be necessary. Whilst it is probably desirable that all users themselves reach a consensus on the management of shared resources, in practice this is difficult, and a combination of public and private actions may be necessary. This aspect is discussed next.
Coastal Resources Institute,
Prince of Songkhla University, Thailand.
There is vast potential to develop coastal resources for aquaculture in Asian countries, as a high demand exists for shrimp products and there is always a need for greater supplies and resources. With the appropriate natural resources and environment in the coastal zone, the culture of Penaeus monodon finally appeared to be a new alternative for coastal resource use. Shrimp culture deals with the integration of land, water and various other natural resources, however, it has also created many external impacts on the environment and on society. This report is based largely on the experience gained from the current condition of shrimp farming development in the region.
Coastal areas which used to be mainly covered with dense mangrove forest and rice fields have been converted by local fishermen and outside investors into ponds for shrimp farming. With a short-term profit incentive, many rice farmers have modified their fields into shrimp farms, causing environmental impacts on the remaining rice fields and other adjacent agricultural areas. The problems of water pollution and deteriorated environments have become so serious that many shrimp ponds can no longer be used. Shifting cultivation to new areas is commonly practised, and presently, large tracts of coastal land that used to be ponds have been abandoned and remain unused.
As it is an important source of income and the cause of a rapid increase in the welfare of the local population, shrimp farming, as such, cannot and should not be stopped. Therefore, there is a great need for appropriate planning and management to sustain the activity in the future. Shrimp culture policy recommendations with specific reference to the manageability of coastal resources is considered very necessary at this point. It is increasingly recognised to be a crucial component in preparing, implementing and reinforcing management strategies, not only in response of short-term problems, but for long-term issues as well. The following problems and recommendations are an attempt to extract an integrated management strategy from the papers prepared for the workshop.
The results presented in this report were obtained mainly through analysis of available reports and drafting an integrated diagnosis that will be used as an aid to draw up a list of problems specific to shrimp farming, as an option for coastal zone management. They are as follows:
A. Water-related problems
The water resources management problem in tropical monsoon countries is basically a matter of “too little” (water shortage in part of the dry season), “too much” (flooding in another season) and “too dirty” (salinity and/or pollution problems throughout the year). Shortages of freshwater leads to a lack of drinking water, mainly in the coastal areas. In addition, the pollution of surface water by shrimp farming poses a threat to the drinking water sources. Apart from water shortages, flooding of lowland areas in river basins also poses regular problems. Storms of lower strength occur every 2 or 3 years causing inundation of the area. In addition, high water levels in the sea often leads to drainage impediment in the rainy season.
With regard to water quality, salinity intrusion is only one of the many factors. The rapid and uncontrolled extension of shrimp farming, may increase the problem of freshwater shortages in the future. There is a large demand for freshwater by shrimp farmers for optional water levels and salinity control in the shrimp ponds, and the economic strength of the companies may further increase pressures on the water supply. The real water quality problems seem, however, to be caused by shrimp farm wastewater discharges. The drainage water of the shrimp farms generally has high BOD, nitrate, phosphate, chlorophyll-a and bacterial concentrations. Other substances like antibiotics and fungicides are used for disease control and pond cleaning and are also present in the waste water. Most of the shrimp farms discharge directly into the surface water system further threatening fresh water sources.
B. Land related problems
Initially, the low productivity of the soils, particularly in the lowland swamp areas, pushed down land values. However, land suitability has hardly been a criteria for site selection of shrimp farms; the availability of saline or brackish water was the major factor. Consequently, the boom in the shrimp farming industry has created an enormous shift in land use which has caused a dramatic increase in the demand for land in the coastal area. For instance, in the area around Pak Phanang Thailand the prices of land went up from 200–300 Baht per rai (US $ 50–75 per ha) in 1985, to about 200,000– 300,000 Baht per rai in 1991 (US $ 50,000–75,000 per ha), but they have since stabilised. Many farmers were inclined to sell their land to shrimp farmers. There has also been an increase in the large scale illegal clearing of forest and mangrove areas for shrimp farming. In this respect, the still present problems of land tenure, land ownership and land registration play a less important role.
The following problems can be considered as those of regional development, land use planning and related law enforcement: (i) the uncontrolled extension of shrimp farm area; (ii) the cutting of mangroves; (iii) associated water demands and water quality problems; and (iv) land toxification. These problems demand a well balanced choice in the utilisation of land resources. A pledge to recognise existing problems related to deforestation and land degradation in upland areas of the region, certainly seems justified.
C. Aquaculture related problems
Optimal growth of shrimp occurs in a salinity range about one third lower than sea water salinity and, consequently, shrimp culture companies tend to mix sea water with fresh water whenever available. As a result, there is pressure on freshwater resources. In spite of mechanical aeration devices installed in most of the ponds, overstocking of shrimp ponds and inefficient feeding practices may lead to low dissolved oxygen levels. An oversupply of feed and fertiliser will also lead to eutrophication and high chlorophyll levels. These problems, plus disease, raise the mortality rate and diminish yields.
After each 4 month crop cycle, shrimp ponds have to be cleaned and disinfected and the polluted sludge has to be removed. After a period of about 5 to 10 years, the ponds have been polluted and toxified to such a degree that they have to be abandoned completely. This land cannot be used for agricultural production anymore, and other appropriate land uses have not yet been identified.
The shrimp farming industry has learned that highly intensive production methods are quite sensitive to internal operational problems such as pond water quality and disease, and to external factors such as climate and water availability. Therefore, they involve large capital risks. In various places in Thailand, there has been tendency to shift from very highly intensive pond systems to semi-intensive systems. This may also be caused by lower prices on the international market. As previously mentioned, shrimp farming creates several problems to the environment regarding waste water discharge, sludge removal and storage, as well as land degradation. Fortunately, some of the major international markets have enforced strict quality control on shrimp, particularly with respect to maximum concentrations of applied disinfectants and disease control compounds. Hopefully, this will lead to reduced inputs of potentially toxic compounds such as antibiotics, herbicides and fungicides, which may slightly reduce the problems.
D. Coastal zone problems
It should be mentioned that shrimp farming along the coast is quite vulnerable as, in general, it is only slightly higher than the normal high water line. Sand ridges, dikes and other coastal protection constructions are absent, and villages and a major road are still located directly behind the coast. The vulnerability to seasonal storms and typhoons is evidenced by the regular flooding and damage that this area experiences.
Coastal zone management problems refer to an imbalance in the use of the coastal land and water resources, i.e. rapid changes from agriculture to shrimp farming with associated land degradation and water pollution. In addition, in some places along the coast huge sea water intake installations have been constructed, consisting of large pumping stations and supply canals built on sizeable jetties. These structures cause substantial local sedimentation and erosion, as they disturb the coastal equilibrium of the northwards current that is directed along shore and acts to transport sediment.
The mangrove areas in the region have been, and are still, cleared for shrimp farming, with unknown consequences on coastal and bay dynamics. What is not yet known is the extent to which the growth of mud flats or sand beaches and the silting of bays, both by sand deposition, are affected by this mangrove destruction.
E. Environmental management problems
The environmental problems related to the present development within the coastal basin include land degradation, water pollution, the destruction of wetlands and mangrove forest and disturbance of the present coastal equilibrium.
Coastal zones are often the dumping bin of wastes from land and sea-based human activities. The most dangerous is the presence of toxic substances, which might return to the food chain through physical, chemical and biological processes which are difficult to control. Shrimp farm pollutants pose a threat for coastal areas.
F. Institutional setting
One of the institutional problems observed in the coastal area is the lack of an authority responsible for integrated regional planning. Various government authorities including the Irrigation Department, the Rural Water Authority, the Tourism Authority, the Public Works Department, and the Forestry Department, bear responsibility for development within the field of their own technical competence. However, it is felt that an ideal set-up is for a competent planning authority to first formulate regional objectives and targets regarding land and water resources utilisation, coastal zone management, industrial development and others.
The tasks and responsibilities of the individual authorities seem to be narrowly defined. However, where regulations do exist, law enforcement is lacking. An example is the uncontrolled change of land from agriculture to shrimp farms and the destruction of wetlands and mangrove forests for the same purpose. Private economic interests seem to prevail strongly in the priority selection for development. However, these economic interests are only short term and the long term effects of environmental degradation are underestimated or neglected.
The critical issues and problems in the coastal area are centred around the conflicts between economic activities and the ecosystem: resulting problems include pollution of surface waters; degradation of the mangrove area and wetlands; and threat of storms, typhoons and flooding. The issues related to shrimp farming development include the extensive exploitation and destruction of natural resources.
Among the different coastal resources, opportunities for sustainable shrimp cultivation are variable and are connected to several human -- and environment -- related factors; not any one of these factors will predominantly indicate the success of failure of shrimp cultivation. The development of a shrimp farm is completely integrated into it's immediate environment and ecosystem. Since shrimp culture development is a part of, and dependent upon, the whole coastal ecological system, coastal zone management questions must be considered and answered. When shrimp cultivation impacts on the environment, it will not only damage the coastal ecological balance, but the damage to the ecosystem will also adversely affect the shrimp farm itself. It is obvious that unmonitored development is not sustainable without consideration of the complete coastal zone.
In order to achieve sustainable development in the planning and implementation of the development of a shrimp farm culture system for a given coastal region, it is necessary to take an integrated approach to the economic, natural, and social environments of the region. However, the rapid socio-economic, aquaculture and ecological changes require immediate, firm decisions and short-term action on a number of potential projects and measures that may improve and/or solve the common problems that face shrimp farm developments. It is also necessary to have a flexible plan and decision-making apparatus because this situation is in constant change. This quick-response action will not hinder long term planning.
These quick response actions include:
The implementation of an integrated water management system for shrimp farming, consisting of a centralised system of freshwater and salt water supply, to prevent coastal erosion by the individual salt water inlet structures and a design of a separate collector drain to which all shrimp ponds are connected for the discharge of wastewater.
The planning of a taxation system and charges for water use and waste water disposal.
The initiation of on-site treatment of the waste water from shrimp farms.
The development and formulation of a sound master plan for conservation of the mangrove and the wetlands and a realistic management plan for the mountain forest area left.
The creation of an eco-tax on land degradation.
The creation of land use zoning and the encouragement of agricultural diversification.
The installation of flood damage reduction measures, flood warning systems, and evacuation procedures.
Dr Paul Guo
Environmental Health Centre,
World Health Organisation, Western Pacific Regional Office,
Kuala Lumpur, Malaysia.
1. Health problems associated with aquaculture
The following may be considered:
Diseases caused by pathogens (e.g. cholera, diarrhoea, dysentery, hepatitis, poliomyelitis, salmonellosis, typhoid fever, meningitis etc.)
Viral pathogens (e.g. hepatitis)
Bacterial pathogens (e.g. cholera)
Protozoan pathogens (e.g. dysentery)
Helminthic pathogens (e.g. schistosomiasis, liver flukes).
Diseases caused by vectors (e.g. malaria, filariasis, dengues, which may be transmitted through mosquitoes associated with water).
Disease caused by toxic chemicals (e.g. pesticides, Hg, Cd, which may give rise to illness such as, food poisoning or cancer.
Disease caused by veterinary drugs. (e.g. through mis-use of drugs during treatment of fish diseases).
2. WHO Microbiological quality criteria for aquaculture
The following microbiological criteria have been prepared for aquaculture by the World Health Organisation.
|Viable trematode eggs*||Faecal coliforms|
(Geometric mean number per 100 ml pond water)
* Clonorchis, Fasciolopsis and Schistosoma.
3. Bacteriological quality of fish from sewage-fed fish ponds
The following bacteriological quality criteria are available for fish culture in sewage-fed fish ponds.
No in fish muscle tissue (bacteria/g)
|Larger than 50||Not acceptable (poor)|
* aerobic bacteria that grow on nutrient and mFC agar at 35°C.
2 Summary of the presentation
4. Control measures
The following measures may be considered in controlling public health risks associated with aquaculture products.
Safe water supply (ensure a contaminant-free water supply).
Adequate sanitation (e.g. provision of toilets).
Treatment of excreta (storage of night soil/sludge for at least 2 weeks before use in fish culture ponds).
Adequate cooking (of fish and aquatic macrophytes).
Control of intermediate host:
chemical (e.g. molluscides).
Control of animal reservoirs.
Reducing water contact (e.g. during bathing, clothes washing and fishing).
Use of protective gear (e.g. gloves, boots).
Depuration of fish.
Proper use of aquaculture drugs.
Daniel F. Fegan,
Aquastar Laboratories Ltd.,
P.O. Box 5, Amphur Muang,
Songkhla 90000, Thailand.
The effect of aquaculture on the environment is of concern to everyone who is seriously involved in the industry. Investment in profitable activities, including aquaculture, will always take place. The nature of most aquaculture industry development is classic in nature. Generally, in the initial stages, it is solely the prerogative of the entrepreneur. At this stage it is generally regarded as a high-risk: high-return venture. It is during this stage, when techniques are still developing, that little thought is given to the long-term. As the industry matures, and the return on investment rates slows and become more predictable, more serious, long-term investment comes into the industry. Their success, however, is to a large extent, dependent upon the long-term potential of the methods developed during the entrepreneurial stage. If these are intrinsically harmful in the long term, the future development of the industry may be put at risk. Therefore it is during the initial, entrepreneurial stage that efforts must be made to promote the viability of the industry in the long term.
This perspective on aquaculture and the environment requires some qualification. It is a personal perspective based on the authors experience in commercial shrimp farming in Asia and Latin America and particularly with a vertically-integrated group involved in the shrimp industry in Thailand. In this respect, the nature of the operation requires some elaboration to appreciate the perspective.
Aquastar is a group of companies located in southern Thailand. The basic premise of the group is that companies do not make good farmers and it is the intent to complement the industry and innovation of the small farmer working on his own land by providing the inputs required, financial, physical and technical. The Aquastar system takes groups of small farmers who want to develop their land as shrimp farms but who, because of their small holdings, are unable to get financing for the capital investment required for both construction and pond operations. As a result of an arrangement between Aquastar, the Bank of Thailand and a local commercial bank (Bank of Asia), involvement in the Aquastar project allows the farmer to access low interest loans for construction and an overdraft facility for operating costs. Aquastar also works with the farmers and the Thai Lands department to look at the individual land holdings of each farmer and re-draws the land boundaries to give each farmer clear title to the area of his pond. This “land re-consolidation” process can be complicated and in some cases has taken up to two years, particularly where land titles are split among different family members. Each farm is designed with a separate water intake and outfall, and its own road and electrical system with backup electricity supply. The farmers get a functional pond with 4 or 8 one-horsepower paddlewheels, a hut providing accommodation and feed storage areas adjacent to the pond, and road access to at least one side of the pond. Aquastar supplies the post-larvae and feed, technical assistance and training, maintains the infrastructure and water/electrical supply (for which a monthly fee is paid), and buys back the harvested crop for processing and export in competition with other processors and brokers. These services are provided through contractual arrangements with the farmers over periods from 15–25 years. The financial arrangements mean that the farmers effectively operate on a full crop credit situation using the pond operating overdraft. The overdraft account is controlled jointly by Aquastar, the bank and the farmer and can only be used for authorised inputs approved by Aquastar. Upon harvest, the income from the harvest is placed in the bank, all of the expenditure and interest payments are deducted and the profit placed in the farmers own account.
The system described differs in many respects from normal contract farming arrangements in that the farmers remain the owners of the land and the company has no authority to remove them from the project. This means that the company has to promote good practices by a combination of training, teaching, persuasion, and similar means. Means of enforcement are limited ranging from restriction of credit access (with the bank) and withdrawal of inputs (which in some cases is commercially counter-productive). The system itself has been extremely successful with over 90 percent of the farmers repaying the pond construction loans within the first four years. A large and viable shrimp farming and service infrastructure has built up in the area over the same period. There are problems, however, with the rate of this development and the standards and practices involved which can and do impact on operations conducted by more responsible groups and individuals. This presentation is intended to give some of this experience and indicate areas where greater attention is perhaps needed in development of a large-scale, commercial aquaculture industry.
The aquaculture industry
The aquaculture industry is often spoken of as a coherent group. In fact, it is a complex interdependent grouping of different, albeit allied, interests, some of whom are more dependent upon aquaculture than others. It is difficult to generalise in terms of management of its development. Target groups must be identified and worked with to find mutually agreeable standards and means of achieving them. For example, feed companies work within a framework of competition with other feed companies. It would be commercially disastrous for one feed company to promote low protein feeds as a means of reducing environmental impact, for example, if others did not since their competitors could claim that this is simply a measure to cut costs by sacrificing quality. Reduced protein content in feeds would have to be done on an industry-wide basis if this were to become a reality.
The peripheral players in the aquaculture industry, those who supply materials to the farmers, also form part of the industry. The greater their dependence upon the success of the aquaculture industry, the greater are their concerns over its present and future well-being. Companies or groups who make substantial investments in supplying the industry have a long-term stake in its future as much as the farmers themselves. Feed mills which were constructed in the areas where shrimp farming is no longer practised must change their investment plans. Closure is the last option. However, supplying the new market areas may result in substantially increased transport costs and a reduction in the ability to offer adequate service to the new market. These companies are often willing to co-operate with the farmers to ensure their continuing livelihood by offering advice and extension services.
The legal framework
The relatively short history of large-scale commercial aquaculture has often meant that regulations and laws have been developed or applied retro-actively. This makes it difficult for aquaculturists and the people involved in its development and regulation to keep up with the legal framework which applies. In some cases, jurisdiction and responsibility for aquaculture developments rests in several government departments with little co-ordination between them. A single government agency concerning the development and operation of aquaculture would be an ideal situation. Failing this, national working groups bringing together representatives of the agencies concerned on a regular basis would help to coordinate efforts on a national level.
Long term vs. short term attitudes
Aquaculture, particularly shrimp culture, is undertaken to make profit. However, the attitude and expectations of the level and time-scale in which the profit is realised, differ a great deal. If there is a long-term commitment to the industry, business or area being farmed, there is a much greater willingness to deal with the problems among and between the stakeholders, whether farmers or investors in the industry. It is where the commitment is solely to the profit to be made in the short term that environmental problems are ignored.
The collapse of the shrimp industry in Taiwan was a major watershed in the commercial shrimp farming world. The repetition of this collapse in shrimp farming areas in Thailand also gave cause for thought. However, there are two lines of thought regarding the lessons to be drawn. The first, most common among governmental, institutional, scientific and technologically aware groups, is that there is a limit to the extent to which we can intensify without endangering the long-term health of the industry. The second, most common among entrepreneurial and short-term investors (including many small farmers) is that shrimp farming has a limited effective life span and there is a need to get as much profit from it during that period as possible before moving on to another area or another investment. This leads to complete disregard for environmental issues since there is no commitment to a particular area or line of business. Unfortunately, these attitudes amount to a self-fulfilling prophecy since the methods of increasing short-term profits usually lead to medium and long-term problems and environmental degradation with subsequent impacts on the farming operation.
Education and training
This is one of the major areas in which progress can be made. A great many environmentally harmful practices are adopted as a result of ignorance of the consequences, particularly in the medium and long-term. Chemical use in particular is prone to this attitude. The use of drugs and chemicals with no knowledge of their effect is sometimes “just in case” they might help. This attitude is encouraged by large numbers of unscrupulous and irresponsible salesmen who wish to find an easy market for bogus products with a high profit margin for themselves. To give just two examples, oxytetracycline and Benzalkonium chloride (BKC), an antibiotic and a disinfectant respectively, are both widely used by farmers despite the fact that studies have shown that almost all of the bacteria isolated from shrimp and water samples are resistant to oxytetracycline, and that BKC is recommended for use at levels of 1–10 ppm, far below those which show any disinfectant effect.
There is a great gap in practice between the research and farm sectors. In many cases, research is regarded as something which happens in laboratories and has no bearing on real life. This credibility gap needs to be bridged if we are to get farmers to accept research results and use them. We try to de-emphasise research and push the development aspect (small “r” large “D”) as a means of reducing this but still the attitude remains. In Thailand, Dr. Chalore Limsuwan has done a great deal to get closer to the grass roots of shrimp farming activities by getting out of the laboratory and into the field but more work of this nature has to be done to improve communication, understanding and technology transfer from the research community into the industry.
For disease-related work involving diagnosis and investigation of shrimp diseases, we have found the short courses run by Dr. Don Lightner at the University of Arizona to be of great benefit. These courses, lasting around 2 weeks, are run every year and give participants “hands-on” experience in the methods and procedures involved in shrimp pathology investigations. We have invariably found that staff attending these courses come back motivated and capable of handling many aspects of shrimp disease investigation in the routine operations as well as providing continuing contact and backup through Dr. Lightner's group. I would strongly recommend this course to those involved in routine shrimp pathology work.
On the subject of academic requirements, we would like to see a greater development of aquaculture pathology and veterinary options in veterinary courses. In addition, adoption of standards of practice and their enforcement, perhaps by keeping an aquaculture vet register, will help maintain professional standards and exclude those who are wrongly or fraudulently advising farmers.
A greater practical content in academic courses should be encouraged. Hands-on experience is a valuable part of an academic education. Provision of more facilities and time for students to work in the laboratory and gain this experience is important. In some cases, reduction of the number of students in classes may have to be considered.
Finally, more commercial and vocational diploma courses may need to be offered to get the practical experience needed to work in industry without extensive on-the-job training. Diplomas and certificates do tend to suffer a reputation as being for people who could not qualify for university degrees. However, they need to be viewed as serving a distinctly different purpose from a strictly academic qualification and should be more geared towards practical and business-related work.
Site selection as taught in university courses is a fairly lengthy process which involves establishing the suitability of a site for an aquaculture operation in terms of a large number of technical, logistic, economic and socio-political criteria. The reality can be far from this. In many cases, the desire is to establish the aquaculture venture on property which has already been acquired or is cheaply available. Investors will shop around until they are told that their venture is feasible. This can lead to aquaculture operations being undertaken on unsuitable or marginal land, in areas with no infrastructure to service the business. Others may build farms in the area, even before successful operations have been established, on the basis that “If X thinks this is a good site, I want to get involved”. Often, the mistaken assumption is that X has carried out a complete feasibility study and found the business to be viable in a particular area.
When Aquastar first started operations, the “current wisdom” was that rice land was not suitable for farming shrimp economically because of the large perceived cost of development, lack of potential for tidal exchange, high pumping costs, possibility of pesticide residues etc. Estuarine and mangrove areas were still being advised as good areas since these were where the post-larval and juvenile shrimp could be found. Our experience has shown these fears to be unfounded. By building on coastal rice land (or any elevated coastal land with suitable soils) the potential for self pollution can be much reduced since tidal influences are minimised (land elevations are high) and the water bodies receiving the discharge are not limited as in the case of estuarine or bay areas.
Similarly, the popular wisdom at the time was that culture of shrimp required water with a salinity of 15–25 ppt to get the optimum growth and that farming operations needed brackish water. Limited fresh water availability led us to operate on an ambient salinity (full strength sea water) basis. Although growth did seem to be slower, this only delayed harvest by around 2–3 weeks and did not affect the economics of the farming operation if appropriate management methods were developed.
Farm construction is often carried out with the aim, at least initially, of keeping down construction costs. This often leads to corners being cut which increase the potential for environmental impact of the operation. In many cases, small farmers simply dig a hole in the ground, use PVC pipe to bring in a supply of seawater and drain into the nearest canal, fresh or salt water. PVC pipe inlets in some cases can extend up to several kilometres. Apart from the effect of the discharge itself, poor pond construction can result in high levels of seepage, even in clay soils. This affects the surrounding farmland, depressing yields and causing the neighbouring farmer to either sell his land or turn to raising shrimp himself.
Establishing proper farm construction standards so that seepage is minimised is of major importance.
The provision of buffer zones between the aquaculture operation and neighbouring farming operations
should also be encouraged. The size of these buffer zones will be dependent upon the quality of
construction of dikes and level of seepage expected.
Encouraging farmers to group together to construct properly engineered farm systems, or the provision of properly engineered farm systems by the government could also be examined. This could be encouraged by providing cheap loans to farmers co-operating in this way or by other means of inducement. In the latter case, payment for the construction could be made by a levy or fee system to the farmers. An alternative would be to restrict planning permission to farms constructed in this way.
To those involved in aquaculture over the long-term, sustainability of production at the highest level of efficiency and cost-effectiveness is one of the most desirable goals. As a statement, that is easy to make, but what can be done in practical terms to develop this? There are several factors involved. The sustainable level will be dependent upon the particular system being utilised. There is a sustainable limit for extensive aquaculture beyond which additional inputs and investments such as feeds and aerators are required. This changes the essential nature of the system and a new sustainable limit needs to be established for the new system.
The determination of what constitutes a sustainable level is not clear and requires some investigation. However, from analysis of data compiled from detailed crop histories at Aquastar (Corpron unpubl.), it was found that, beyond 6,000 kg/ha shrimp biomass in the pond, there was a marked reduction in feeding rate and daily growth of the shrimp. We interpreted this to mean that this represented a level at which the shrimp were becoming stressed or had reached some sort of limit to efficient growth. This was taken as being a reasonable estimate of a sustainable level. It must be emphasised that this level is not definitive and is our estimate of a sustainable level in the particular system within which we are working. Neither does it represent an absolute limit. Higher yields have frequently been obtained but we would like to discourage the tendency to chase yield records which is all too prevalent in areas developing a shrimp industry.
Changes in the system, whether they be physical, environmental, or changes in management technique, may also change the characteristics of the system sufficiently to require that the sustainable level be re-estimated. Some work has been done on this with respect to aeration, for example. An old “rule of thumb” estimate for aerator requirement stated that 1 Hp of aeration should be provided for each 600– 800 kg of shrimp desired to be harvested. Work carried out by Hopkins in the US on shrimp ponds indicated a relationship between daily feed input and aerator requirement to maintain dissolved oxygen levels. All of these estimates give broadly similar results when applied to our system which may suggest that there is some justification in adopting the sustainable yield approach.
Farmer/industry groups and self-help schemes
The encouragement of farmer groups and self-help (not self-interest) schemes could play a major role in managing aquaculture development. Grass roots schemes like this benefit from the self motivation of the farmers which makes implementation very simple and we have found peer pressure to be the most potent form of control. With the right organisation, co-operative means of dealing with common resources, and common problems, can be found and implemented. For example, in Surat Thani in southern Thailand, shrimp farmers using the same water area found that there were problems with self pollution due to uncontrolled discharge and intake of water by farmers in the area. They co-operated to solve this by agreeing to co-ordinate intake and drainage of water to reduce the potential for mixing of the two. The co-ordination is done by means of flags, a green flag indicating that water should be taken into the pond and a red flag indicating that it should be drained. Once again, this demonstrates that, given the impetus, farmers can be extremely innovative in solving their own problems.
The problems faced by the Thai shrimp industry as a result of the yellow-head disease in 1992 and early 1993 resulted in the loss of an estimated 20–25 percent of production. Early recognition of the spread of the problem, allied with research on its causes carried out by the National Institute for Coastal Aquaculture staff in Songkhla, resulted in the recognition of a new virus (named Yellowhead baculovirus (YBV) as the causative agent. The industry-wide effect of the disease prompted the formation of a national task force on the yellowhead problem bringing together all the concerned parties, comprising industry, government and academic sectors. As a result, short and medium-term research priorities were quickly defined, projects prioritised and started, and regular meetings held to update on the state of knowledge. This gave a rapid and co-ordinated response which probably helped to limit the spread of the disease. This was the first time such a task force had been set up to deal with a specific problem. It's success in bringing about a co-ordinated response and faster communication makes it worth repeating should such a situation arise in future.
Many areas of development of a successful industry are too large for individual companies to be able to afford. The risks of duplication and high costs tend to deter companies from carrying out work and it is often left to the public sector to take the lead. Unless good communication and co-operation between the two is maintained, public sector research can become detached and aloof from the needs of industry and industry, since it does not pay directly for the research to be carried out, may push projects which are of limited relevance and will not have any intention of applying. In other cases, public sector labs or researchers are prohibited from carrying out joint work with a private sector company. This situation can exacerbate the communication gap between researchers and the industrial community with each side accusing the other of having no real interest in the work of the other. The priorities for each sector also differ and a “catch 22” situation can exist where the private sector is waiting for the public sector to take the lead and vice-versa.
In an attempt to bridge the gap, we are presently involved, with other private sector companies and two Thai government agencies (Prince of Songkhla University and the National Science and Technology Development Board) in attempting to put together an organisation for carrying out industrial and commercially applicable research, particularly in areas where inter-company and international cooperation is necessary to be able to afford the work to be done. The novel aspect of this venture (provisionally named the International Commercial Aquaculture Research Institute or ICARI) is that it will be governed by a group of shareholders consisting of private companies. These shareholders will decide jointly on research priorities and will contribute on a project-by-project basis. The final shape of ICARI will depend very much on the decisions of these shareholders. There is insufficient space to go into this in detail and further information can be obtained from Prof. Timothy Flegel, whose address can be found in the list of participants of this meeting. This kind of co-operation should be encouraged wherever possible as it allows industry to tackle issues on a large scale and allows researchers to work on commercially applied development projects with a good expectation that these are what industry really wants and will apply. This is a different kind of self-help activity which could be encouraged by governments and international agencies, perhaps in the form of tax breaks for the companies involved, allowing these organisations to have access to grant funding or simply providing for the possibility of private sector research to be carried out in public sector labs.
The growth of the aquaculture industry as a profitable business inevitably leads to the need for service activities, particularly in the field of water and soil quality analysis and disease diagnosis and control. The standards of different laboratories or organisations offering these services is highly variable. Some labs are little more than sales tools for chemical and drug salesmen. Some labs will take samples of shrimp, water or soil from a farmer and, within minutes, give a definitive diagnosis of the problem and a solution, usually involving drugs or chemicals which they also sell. Labs which actually carry out proper characterisation and identification of the problem are criticised as being too slow and, since they do not generally offer a “quick fix” cure, of little practical use to the farmer.
These labs and individuals need to be weeded out if the industry is to develop in a responsible manner. Registration and quality assessment of the labs and their staff should be carried out periodically to ensure that standards and codes of practice are being maintained. Where codes of practice are lacking, these should be developed so that farmers can be sure that the service and advice they get is professional and appropriate.
Control of drug and chemical use
The easy availability and lack of regulations (or their enforcement) has meant that drug and chemical use is rampant in many shrimp farming countries. In most cases, this is due to the ignorance of the farmers and their being preyed upon by unscrupulous salesmen. However, there is a distinct lack of work being carried out in Asia towards registration and characterisation of useful drugs and chemicals for aquaculture use and residues in aquaculture products. Aquaculture products should have permitted levels of residue as are currently the case with poultry and other livestock used for food. These should be based on research carried out into the pharmacokinetics of the drugs involved. In addition, the arsenal of permitted drugs is small and the use of such drugs in tropical aquaculture environments is not well understood. We need more work in this area to allow us to develop a reasonable medicine chest which can be used within the framework of recommendation by a qualified veterinarian.
The use of dangerous or harmful chemicals, or those which are not approved, should be penalised. In addition, the selling of these drugs and chemicals or advocating their use should also be subject to some level of control and stiff penalties handed to people found to be doing so in a fraudulent manner.
Consultancy registration and standards
There are a great many people in the aquaculture industry who would call themselves consultants. In some cases, these consultants are honest, well-qualified individuals who offer a professional service to clients within the area(s) of their particular expertise. However, the demand for advice and assistance in a “boom” industry such as shrimp farming is such that many consultants have limited or no knowledge and perceive their consultancy as a means of making money from people who know even less. There are numerous failed projects all over Asia which testify to this problem. Investors as well as the responsible consultants need to be protected from the bad image and fraudulent practices of these groups and individuals. References do not provide sufficient safeguard since few people will admit to having been duped, even fewer bother to check up and quite a few cannot be traced as they have gone out of business. Even when references do reveal problems the “consultant” is usually ready with a plausible excuse.
The development of a list of accredited consultants or a database of consultants backgrounds would be an invaluable source of information for anyone looking at the possibility of an aquaculture investment. The idea of a Chartered Institute of Aquaculture Consultants is not new but needs some governing group or body to take the first steps in developing the concept.
Small farmers may be simple but they are far from stupid. The level of innovation which is displayed by small farmers when something is perceived in their own interest is quite impressive. Simple, cost-effective solutions which are practical and pragmatic are, in my experience, much better left to the farmers themselves. Given a framework or limit within which they must operate, whether legal, physical or environmental, farmers will themselves find the best solution. The key point is in building or defining the framework within which they must operate. Once the framework is set, the most obvious and often easiest solution is to circumvent or avoid it. If this avenue is cut off the farmers will comply in the most cost-effective means possible.
Information and knowledge base
Information and its availability to local farmer groups and those working to support them is limited. Aquastar ultimately had to establish its own library to be sure that key tests and journals were available to allow technical and research staff easy access. Institutional library holdings were often limited or patchy due to budget constraints and the ending of particular grant funding which gave assistance to buy journals. The provision of assistance to establish and maintain, locally, information facilities to allow aquaculturists, research, technical and extension easy access to information on aquaculture developments would be a major benefit in promoting better understanding and more efficient dissemination of responsible practices.
There is also a drastic need to provide regular and periodic updates of current status of knowledge of aquaculture operations. This is particularly true in developing countries. The available information base is often small or non-existent, and frequently outdated. People still refer to old textbooks and papers as authoritative tomes, despite the many changes and advances in our knowledge of aquaculture techniques, species biology and culture methods and environmental impacts. This can lead to the persistence of undesirable ideas or inefficient methods of farming.
Technological developments to reduce environmental impact
Environmental considerations are a major concern and a constraint to the development of the US shrimp industry. As a result, many research activities have been, and continue to be, undertaken to reduce these and allow the industry to develop. The Gulf Coast Research Consortium combines many groups with the aim of reducing the US shrimp trade deficit, partly by substituting imports with home-grown shrimp. Work on low environmental impact techniques is being carried out as part of this effort. A paper presented at the recent World Aquaculture Society meeting in New Orleans gave some impressive results and yields using very low rates of water exchange. This kind of work needs to be continued and attempts made to apply it on a larger scale to demonstrate its commercial feasibility.
Crop insurance is quite well-developed for salmon culture but is in its infancy for other cultivated species. The main concern of the insurers is that the risks are known and quantifiable to a sufficient extent so that they have a reasonable basis for calculation of the premium. Although some shrimp crop policies are available, the requirements of the insurers are generally such that it is only available to large companies with a fairly high level of technical expertise. Premiums are generally quite high and claims procedures are complicated with many deductibles or exclusions. Further development of the insurance market is desirable but will require more information on risks associated with particular practices. Limiting of insurance cover to farmers practising sensible, sustainable culture methods would be one way of encouraging their use.
Summary and recommendations
It should be recognised that the aquaculture industry consists of many different groups, not all of whom are equally dependent upon its success. Any actions should be taken after discussion and agreement with those groups with the greatest involvement in the long-term well-being of the industry.
Means should be found to discourage the short-term profiteering which leads to many environmentally unsound practices and to encourage those groups and individuals who take a long-term view of the industry.
The level of educational support for aquaculture needs to be reviewed as a means of training qualified staff and teaching environmentally sound attitudes towards aquaculture practices.
Scientists and researchers should be encouraged to go into the field more often. The benefits from this are two-fold. Firstly, they will be able to keep in touch with commercial practices. Second, this will encourage farmers to listen to the advice given by the scientists and to respect their opinions leading to a much better informed aquaculture community.
Key areas of shortage should be identified (e.g. veterinary aquaculture) and courses established to supply these areas.
Academic and vocational courses should have a high practical component to ensure that the graduates are capable of working in their chosen fields.
Vocational courses should be emphasised distinctly from degree courses with a view to supplying the specific need of industry for practical and business skills.
Site selection, or identification of suitable sites, should be carried out by independent, responsible bodies or according to guidelines stipulated by these. Construction of farms on sites which are unsuitable should be prohibited.
Farmers should be encouraged to build along open coastal areas and to use ambient salinities to avoid discharge and pollution problems associated with tidal and restricted bodies of water.
With sustainability as a goal, different systems of culture should be characterised as to their sustainable limits. The effect of different inputs on these levels should be investigated.
Methods of partial harvesting need to be refined so that a farmer can easily remove part of the crop once the sustainable level is reached, leaving the rest of the shrimp to be cultured to a larger size.
The use of stocking densities as a criterion should be changed to one of biomass. This will avoid difficulties related to differential survival rates and yields.
Farmer and industry self-help schemes should be encouraged as a means of allowing them to seek their own solutions to problems or compliance with regulations.
Frequent contact between government, academic and private sector representatives should be encouraged as a means of tackling development issues jointly and gaining the support of the private sector for the initiatives taken.
Governments should provide accreditation of labs and services offered to the aquaculture industry to limit the opportunity for unscrupulous groups and individuals to prey upon the ignorance of the farmers and to promote a climate of professionalism in the service sector.
Drug and chemical use should be monitored and regulated to prevent the use of harmful, dangerous and short-sighted methods. Farmers should be trained and have access to information on the proper application of approved chemicals to avoid the tendency to overdose as a safety measure.
Consultants and consultancy companies should be registered to protect farmers and investors from bogus or fradulent operators. Regular audits could be made to ensure that standards of professionalism are maintained.
Farmer innovation should be harnessed by identifying objectives and desired modes of operation and building a framework to promote and encourage these rather than by issuing highly detailed methodologies which may not represent the most efficient and practical means.
Information databases should be set up so that farmers and researchers have ready access to up-to-date information. Regular updates of “state of the art” techniques and technologies should be provided to prevent the use of old, outdated texts being used as instruction handbooks by new farmers.
Researchers should be able to communicate regularly with each other and industry to develop technological improvements to reduce environmental impacts and promote their widespread use.
The legal and regulatory framework concerning aquaculture should be simplified as much as possible and/or co-ordinated to ensure that all of the government bodies concerned work together towards a common objective.