Previous Page Table of Contents Next Page

6. Options for environmental management of coastal aquaculture development

171. In this section, a number of environmental management options are presented, many of which are already being implemented. First, a general management framework for protection of coastal environments is described (6.1). An overview on the integrated coastal area management approach is given (6.2) and legislation governing coastal aquaculture is discussed (6.3). The role and functions of planning and management of coastal aquaculture development are addressed (6.4) and environmental management options at farm or project level are summarized (6.5). It is emphasized that these management options reflect approaches which are - to some extent - conceptually different.

172. Circumstances at local, district and central government levels will have to be considered in the choice and the implementation of these management options, possibly involving a selection or combination of relevant elements of these options. This choice should be based on a proper understanding of the interactions between aquaculture and the environment as well as adequate knowledge of environmental impact assessment methods and procedures.

6.1 A Management Framework for Protection of Coastal Environments

173. A management framework for protection of coastal environments follows, adapted from GESAMP (1991b). Environmental impact assessment efforts should be guided by predetermined development priorities and well-formulated environmental protection objectives. It is equally important that, based on environmental impact assessment, the environmental performance of coastal activities is monitored and controlled according to well-defined directives and regulations specific to those activities which pose a significant threat to the coastal environment.

174. GESAMP's environmental management framework has three components: the management planning process, the environmental impact assessment process and the regulatory process (see Figure 17). Ten action levels are specified in relation to important considerations and factors. This framework and the management processes it describes are continuous institutional functions and not functions that are triggered only by individual development proposals.

175. Within the management planning process both overall and specific goals (developmental benefits and desired environmental conditions) are adopted, and values and resource uses identified and prioritized. At action level (3) the task is to determine the environmental characteristics that sustain specified values and resources, and the extent to which these can be changed without causing harm.

176. These limiting values are normally expressed as environmental quality criteria that can be used to formulate site-and contaminant-specific standards. As stated before, due consideration should hereby be given to size/intensity of the waste-generating activity and the environmental capacity of receiving waterbodies. Fish consumption patterns should be reflected in contaminant levels established for edible species.

177. The environmental impact assessment process includes action levels (4) and (5) where the current environmental situation is assessed, and existing and potential inputs are identified and quantified. At level (6) current and projected resource uses are appraised in view of the environmental capacities determined. If necessary, means to reduce effects are formulated which should also include adaptation and modification of resource utilization. In the case that environmental capacity is exceeded, envisaged development will have to be reassessed. If required, all feasible mitigation and control options are compared at level (7) to select those that are most useful and efficient in meeting specific goals and priorities.

Figure 17: Comprehensive management framework for protection of marine and other environments (from GESAMP, 1991b)

178. Within the regulatory process, operational and corrective action is taken at level (8), whereby required controls are applied to activities carrying environmental risks as identified at level (5). Regulatory measures could range from imposed limits on the chemical concentrations in effluents, to the temporary banning of certain products and practices. They could also involve financial incentives or disincentives, subsidies, fines, imposed waste treatment or public awareness campaigns including consumer education. The effectiveness of control measures is measured - in level (9) - through monitoring programmes: first, to ensure compliance with controls imposed on certain activities, and second, to regularly measure those variables that are being used to indicate that specific goals are being achieved. Finally, there needs to be a commitment to act if the monitoring programme indicates either that there is a lack of compliance with controls, or that they are ineffective, or a trend indicates that limiting criteria are in danger of being approached. Such action - level (10) - following monitoring completes the management loop.

Basic prerequisites for implementation of GESAMP's management framework

179. With regard to implementation of these management processes, GESAMP emphasizes the following requirements:

180. Environmental planning: There is a requirement for coordinated multi-sectoral planning of developments that have the potential to affect the marine environment. This should include the assignment of environmental goals and priorities, resource allocations, and the preparation of integrated management plans for all relevant sectors.

181. Environmental impact assessments: All proposed large-scale developments and investments that are likely to have direct or indirect effects on the marine environment must be subject to a prior assessment. This assessment should encompass physical, chemical and biological changes, risks to human health, amenities and resources and, particularly, the benefits and detriments of the proposal to the satisfaction of environmental and development goals.

182. The need for precaution: Precaution is integral to scientific risk assessment. A pessimistic approach is essential to allow for uncertainties in measurements and calculations incorporated into predictions. Science should be used to resolve and reduce these uncertainties by providing accurate information on the relationship between the practice and its effect on marine resources. A further, and entirely complementary, use of precaution is to take all practical and economically feasible measures to minimize environmental contamination through inter alia good housekeeping and the application of efficient and low-waste technologies.

183. Acceptance of change: Implicit in this framework is an acceptance that change is both a feature of the natural environment and an inevitable consequence of human activities and social development. Human intervention to limit and control such changes is both necessary and legitimate.

Basic criteria for adapting an environmental management framework to coastal aquaculture

184. The following basic criteria may also prove useful in formulating, establishing and improving the institutional and regulatory framework for environmental management of coastal aquaculture (adapted from Muir and Baird, 1991). The environmental management system should be characterized by:

185. Simplicity: It should be as easy as possible to operate, and be clear and understandable to all those involved, including the public.

186. Equity: It should operate fairly on all those involved in 'using' coastal resources, according to the degree of use. This should extend to apply to all users, as well as aquaculturists.

187. Capacity: Implementing institutions may require strengthening through training and equipment; however, due account should be given to actual requirements and financial resources available.

188. Fair distribution of costs: The system should not be too burdensome, and either overload or excessively inhibit the activities it is designed to cover, or place too great an imposition on the institutions responsible for its operation.

189. Rationality: It should be based on logical and scientific foundations, providing testability and, once operational, offering predictive power.

6.2 Integrated Coastal Area Management (ICAM)

190. Coastal aquaculture is one of many activities utilizing coastal resources. The lack of appropriate cross-sectoral coordination and control of development of the various coastal activities has, to some extent, contributed to natural resources depletion, environmental degradation and resource-use conflicts. In many cases, it may be required that coastal aquaculture is developed within the overall framework of a coastal area planning and management programme. A brief overview on ICAM follows, which may prove useful for coastal aquaculture development planners.

191. There is a variety of approaches and concepts to coastal management. Sorensen and McCreary (1990) list and review 11 strategies for management of coastal resources and environments, including national economic planning, broad-scope sectoral planning of coastal uses or resources, regional seas, nation- or state-wide land-use planning and regulation, special area or regional plans, shoreland exclusion or restriction, environmental impact assessment of coastal development proposals, mandatory policies and advisory guidelines, acquisition programmes, coastal atlases and databanks.

6.2.1 Definitions and concepts related to ICAM

192. The coastal area is an interface between the land and the sea which extends inland and seaward to a variable extent. The term "coastal area" refers to a geographic space which has not been defined as a zone. Defining boundaries of a "coastal zone" in a given area ("zoning") will depend on political, administrative, ecological and pragmatic considerations. For example, where there is a broad array of possible coastal issues and impacts the boundaries may be taken as those of the area with highest intensity of conflictual use. If watershed issues are of concern, then an inland extension of the "coastal management zone" is necessary. Zoning, i.e., the process of defining the boundaries of a coastal area to be developed and managed, is an essential component of ICAM.

193. ICAM is both a concept and a tool for inter-sectoral coordination. It incorporates modern principles of decision-making in planning and natural resources areal management, interdisciplinary processes, intensive information bases. It is foreseen as an effective general framework for dealing with the interactions of the various uses of the coastal areas, based on consultation and participation of resource users and managers. ICAM aims at a balance between a variety of compatible uses whereby economic and social benefits are maximized and conservation and development become compatible goals. Integration hereby refers to (1) the various sectors (e.g., fisheries, waste disposal, marine transport), (2) to the tasks of which ICAM is comprised and (3) to the economic, technological, ecological, and institutional aspects involved.

194. ICAM is typically concerned with resolving conflicts among the many uses of coastal resources and trying to determine the optimal mix of uses over time, recognizing the dynamic nature of both resources and demands on those resources. An ICAM programme usually has the following attributes:

- It is implemented by government in response to very evident resource degradation, hazard exposure, and multiple-use conflicts, or as part of planning for regional or national economic development.

- As a programme it is ongoing and therefore distinct from a one-time project. It has longevity and is usually a response to a legislative or executive mandate.

- The programme relates to a physical area with landward and seaward limits defined as the coastal zone.

- It addresses a specific set of objectives or issues. These issues, and/or the relative importance among issues, are likely to change over time.

- The programme has an institutional identity, i.e. it is identifiable as either an independent organization or (more often) as a cooperating network of organizations linked to by formal mechanisms which allocate tasks among the organizations (entities, agencies).

6.2.2 Programme formulation

195. Objectives and priorities as well as content and complexity of an ICAM programme will vary from area to area according to development trends, conservation needs, traditions, norms, governmental systems, and current critical issues and conflicts. But compatible multiple-use objectives should always be the main focus. If human and financial resources are limited, ICAM programmes can be simplified to include only the following components (FAO, 1991c): (i) harmonization of sectoral policies and goals; (ii) cross-sectoral enforcement mechanisms; (iii) a coordination office and (iv) permit approval and environmental impact assessment (EIA) procedures.

196. According to FAO (1991c) ICAM programmes should relate to national planning and possibly to specific coastal development plans. They should provide advice to developers and managers, coordinate agencies and stakeholders towards agreed goals. They should provide opportunities for analyses of options, of legislation and institutions and for the creation of an information base. Some considerations which may guide the formulation of ICAM programmes are provided in Annex 7. An example for the development of an ICAM plan (Chua 1989) is given in Figure 18. Chua (1991) summarized processes in identifying ICAM issues and formulating ICAM plans (see Figure 19).

197. ICAM planning should start with a "strategy plan" that lays the foundation for the legislation or the executive order that is needed to authorize the programme development stage that follows. The strategy plan should (FAO, 1991c):

- state clearly the objectives of the ICAM programme;
- indicate how theses objectives will be met;
- assign responsibility for the programme to a particular agency;
- identify the funding necessary for programme development;
- ensure collaboration among the various sectoral agencies and private interests involved;
- state the time limits involved for various stages of programme development.

6.2.3 The information base

198. Information needs for ICAM planning should be determined in a preliminary analysis of the given situation, based primarily on existing data (Clark, 1991), aimed at:

(a) estimating the levels and spatial patterns of coastal activities, at present, and for target years in the future;

(b) estimating demands for use of coastal resources as a result of the activities in (a);

(c) analysing possible means for producing/satisfying the demands estimated in (b);

(d) analysing the impacts of the activities on coastal ecosystems, based on both waste discharge to the coast and on space occupancy of coastal areas;

(e) formulating and evaluating strategies for ICAM (a strategy being comprised of a mix of outputs, physical measures, operating procedures, implementation incentives, institutional arrangements, and financing programme);

(f) presenting the results to decision-makers and interested parties.

Figure 18: An example for the development of an integrated coastal area management plan (from Chua, 1989)

Figure 19: Processes in identifying coastal area management issues and formulating coastal area management plans (from Chua, 1991)

199. Some principal types of information needed for ICAM are given in Annex 8. Inventories, atlases, databases related to resources, habitats, environments and present or potential development activities are considered very useful in ICAM. Particularly useful are geographical information systems (GIS) which assist in retrieving, compiling and using existing but not easily available information on resources, environments and uses (Meaden and Kapetsky, 1991; Cendrero, 1989a; Kam, 1989; FAO, 1989a; Butler et al., 1988; Kapetsky et al., 1987; FAO, 1985b). These also help to identify data gaps, reducing the need for additional information to a minimum. For examples on the collection of ICAM information, the reader is referred to coastal environmental profiles which have been elaborated for several areas in Southeast Asia (McManus and Chua, 1990; White, Martosubroto and Sadorra, 1989; Chia, Habibullah and Chou, 1988; Paw et al., 1988; Chua et al., 1987).

6.2.4 Management strategies

200. Management may be reactive or proactive. Reactive integrated management is an issue-driven process and the nature of the particular issues dictates the type of programme to be created and the boundaries of the programme. In this mode, the effort and expense required to set up an ICAM programme would not be justified unless there were multiple issues of importance to be addressed. However, when there is a conflict between different interests, corrective measures might be very difficult to apply. Proactive integrated management is part of the development planning. It may help to avoid the most serious conflicts by making the "right" decisions early in the process. This consideration is particularly important for developing countries. Some premises and considerations for a management strategy in ICAM are given in Annex 9.

201. Several specific management strategies have been used as elements of integrated coastal resources management programmes (Clark, 1991; Lowry, 1989):

202. Through zoning schemes, space and resources are allocated, explicitly and legally, to different types of uses which may include nature and biodiversity conservation.

203. Protected areas (and biosphere reserves) may provide custodial protection for critical or particularly sensitive areas and species. However, protected areas may also be coupled with multiple use zones; an approach which would include a strictly protected "core area" linked with adjacent buffering areas and multiple use zones. This combination is less likely to result in strong resistance than undifferentiated reserves.

204. Shoreline exclusion zones are designed to specifically prohibit or significantly limit uses within a strip or band in the coastal zone. The shoreline exclusion zone is primarily used to ensure public access, preserve the landscape and protect shore areas from erosion. The areas subject to shoreland restriction are typically landward to the high water mark.

205. Specific zones may be designated to priority activities. The priority activity in a particular zone may acquire "predominant use" status. Other "permitted uses" can be accommodated, but only as long as they do not jeopardize the predominant use. Zoning designations are usually designed to anticipate and coordinate future uses rather than respond to specific development proposals, as do permit systems.

206. In the typical permit system, specific coastal uses within a specified coastal zone are subject to authorization. Applications for permits usually require information about the intended activity and the nature of impacts likely to be generated by the activity (see sections on assessment of environmental impacts).

207. Facility-siting guidelines are special requirements for particular projects likely to have major coastal impacts. Some facility guidelines specify a particular review process with which a project must comply. Others specify standards with regard to emissions and effluents that a facility must meet (see sections on assessment of environmental impacts).

208. Establishment of ownership and tenure systems may be the most certain way to protect and manage critical habitats and their resources. If the areas are owned by the state, access may have to be restricted and controlled to avoid degradation due to competition. Exclusive user rights may be given for certain types of resources or areas, to coastal communities or to private interests. The devolution of user rights and management responsibilities to coastal communities may help to promote cost-effective coastal management. The use of financial incentives or disincentives may also help to control extraction or pollution rates.

209. Communication and negotiation patterns between parties involved in ICAM may need to be improved (see Lowry, 1989). Facilitated policy dialogues deal with policy conflicts at the planning stage. A neutral facilitator organizes meetings to resolve inter-agency or other conflicts. The facilitator helps the group structure an agenda and guides discussions in an orderly fashion. Mediation is important in multiparty resource-use or site-use disputes. This involves the use of a non-partisan party who designs a process which ensures that all relevant parties are represented and identify their interests; and who makes it possible for disputants to present options that deal with the interests of each party and to draw up agreements.

6.2.5 Implementation and enforcement

210. Experience in ICAM is limited because the integration of coastal areas development and management is a relatively new concept. Experiences in the planning and implementation of ICAM made so far in developing and industrialized countries are very diverse (Clark, 1991; Burbridge, 1991; Chua and Scura, 1991; Sorensen and McCreary, 1990; Chua and Pauly, 1989; Juhasz. 1991; Bashirullah et al., 1989; Merschrod, 1989; Chen, 1989; Katz, 1989; Kennedy. 1990; Chong and Manwan, 1987; Charlier, 1989: Cendrero, 1989b; Archer, 1988; Hildebrand, 1989; Gubbay, 1990). Coastal area management approaches specifically designed for coastal aquaculture in industrialized countries also exist (see for example Black, in press; Pedersen et al., 1988).

211. There are many ICAM-related strategies, policies and plans produced by experts governments and international organizations. However, implementation of ICAM programmes has often faced serious difficulties and constraints which led to poor achievement of ICAM objectives.

212. Main difficulties and reasons for failures of ICAM programmes include: lack of technical and financial support; lack of long-term political commitment; issues of common property resources and allocation of resource user rights; lack of people's awareness, motivation and participation; inadequate institutions and administrative fragmentation; inadequate definition of coastal zone boundaries; lack of clearly stated goals; lack of compatibility with sectoral development plans; dominance of "crisis" management over long-range planning and proactive management; inadequate information bases and research capacity; lack of trained personnel; difficulty to identify the competent counterpart agency.

213. Financial constraints are a particularly serious matter, especially for developing countries. Sources of funds for ICAM need to be identified which may include licences and user fees and taxes under the "polluter pays" and "user pays" principles, international grants and softloans, percentage on development programmes, etc.

214. Some level of enforcement is required in all management programmes. This presumes the existence of an operational legal framework and entails costs. Enforcement costs depend on the level of people's adhesion and cooperation as well as on the system of regulatory control measures, incentives and disincentives adopted. Right-based systems appear to be cheaper to enforce as they can rely more on self-enforcement.

6.3 Legislation Governing Coastal aquaculture

215. Legislative and administrative measures aiming at the environmental compatibility of the various aquaculture practices should be considered within the broader legislative context governing coastal aquaculture. Many countries have little or no aquaculture-specific legislation purposely designed to protect or allow this activity. However, many aquaculturists must cope with complex laws and regulations on land tenure, water use, environment protection, pollution prevention, public health and fisheries in general. Few of these are specifically drafted to promote or regulate aquaculture, and confusion, conflicts and overlapping exist (Van Houtte et al., 1989).

216. A particular legal regime for coastal aquaculture in an individual country must ensure that the needs of aquaculturists are met, but also that existing or future relevant laws are carefully integrated. Purpose and scope of legislative measures should be well defined. Legislation should clearly take into consideration:

(a) the purposes of the industry: e.g., food production and market (local or export), employment, recreation, etc.;

(b) the resources or species used;

(c) the system or elements utilized for production; and

(d) the environment in which production is conducted.

217. Various preventive and remedial measures for controlling and managing the environmental impact of aquaculture have been developed and applied (see for example Van Houtte et al., 1989; Bye, 1990; Quincy, 1990; McCoy, 1989; Howarth, 1990; Rosenthal et al., 1988). A summary of control options used in various industrialized countries is given in Table 15. Van Houtte et al. (1989) identified five regulatory approaches, including (i) land use planning and zoning, (ii) control over installation and operation, (iii) discharge limits and pre-discharge treatment to meet limits, (iv) fiscal incentives, and (v) prohibitions.

218. When planning the use of land and water resources the zoning of areas for aquaculture purposes should be included. Also, once protected areas such as parks and nature reserves are established, it should be clearly stated where and under which conditions aquaculture practices would be permitted, if at all. Aquaculture practices should not be permitted in heavily polluted waters. Pollution hazards to aquaculture and its produce should be properly assessed in high-risk areas.

219. Environmental impact assessments (EIA) or environmental impact statements (EIS) on the potential effects of proposed large-scale aquaculture operations may be imposed prior to the authorization for the installation of an aquafarm. In the former, the investor is usually required to make a general statement of the effects of the project on the environment; in the latter the statement is much more rigorous and may require all facts about the project and a detailed estimate of its effects on the environment.

220. Specific coastal aquaculture activities/installations may be termed and classified as environmentally critical undertakings, being subject to special declaration or authorization procedures.

Table 15: A summary of aquaculture control options used in various industrialized countries (from NCC, 1989)

Control option






New Zealand




Substantial legislation


Distance limits

- between sites



- from conservation areas


Limits on production


- per farm



- cage area or number




- by volume


- by stocking density


Water depth regulations



Restricted areas


Moratorium on new farms



Regulations on ownership


Environmental Impact Statement (EIS) required


Water quality monitoring



Management plan required


Regulations vary with farm size




221. The installation of effluent quality control equipment or water discharge treatment facilities may be promoted through fiscal incentives like direct subsidies or tax deductions and exemptions. Charges or taxes on polluting effluents also exist.

222. The release of pollutants into adjacent waters through aquaculture or other industries may be regulated by setting quantitative and qualitative limits to the waste waters discharged. Also, in order to meet these limits, the treatment of effluents prior to discharge is often required.

223. Legislation should be enacted to regulate and control the movement of eggs, larvae/juveniles and adult stages of exotic fish species, which may be combined with compulsory certification of stocks to be free of certain diseases and banning of all movements of diseased stocks. Adoption and application of the EIFAC/ICES Codes of Practice on introductions and transfers of marine and freshwater organisms is recommended (Turner, 1988; Arthur and Shariff, 1991; Shariff and Subasinghe, 1990).

224. Coastal aquaculture products should conform with safety standards for seafood before they are allowed for human consumption (see, for example, WHO Expert Committee, 1974). The FAO/WHO Codex Alimentarius Commission is currently preparing a draft code of hygienic practice for the products of aquaculture (FAO/WHO. 1991 a), which includes most parts of a draft code of practice for the use of veterinary drugs in aquaculture (FAO/WHO, 1991b). GESAMP (1991c) proposed a code of practice for the use of inhibitory compounds in aquaculture, which is given in Annex 10.

225. Constructive and adaptive regulations are needed in order to avoid obstacles to coastal aquaculture development and, equally, to ensure that the environment is adequately protected. Apparent over-regulation and legal uncertainties can, however, hamper aquaculture development, by creating significant barriers to the establishment or the continued operation of aquafarms. It is emphasized that the particular role of aquaculture in utilizing land and water resources for food production calls for an integrative and flexible environmental legislation which is enforceable, effective and adapted to the socio-economic conditions and development needs in local communities, particularly as prevailing in developing countries.

6.4 Planning and Management of Coastal Aquaculture Development

226. National aquaculture development plans are always useful not only for identifying where in the country aquaculture should be developed, how this development should take place and the time frame and the resources required. They are also useful for regulating such activities to ensure better chances of success and to minimize developmental and environmental conflicts.

Past experiences

227. It has been stated that most aquaculture activities have been developed through isolated and uncoordinated efforts (Pillay, 1990). The growth of aquaculture in the Asian region has generally not been guided by relevant national development plans nor has the industry been adequately managed (Chua and Tech, 1990). Obviously, growth of aquaculture was and is still being driven by market forces. Most private sector-backed development follows these market forces wherein profitability determines the rate of expansion. Comparatively high profit margins have, for example, encouraged the large-scale development of shrimp farming, which, however, is now facing increased international market competition, resulting in considerable price and demand fluctuations and marketability problems. Unfortunately, too much concentration is often given to short-term profits and insufficient attention to long-range planning (see, for example, Hwang, 1992).

228. As for Asia, Chua and Tech (1990) also state that there was no effort to study the opportunities for aquaculture development and their social and environmental implications in the transfer of aquaculture technology from one country to another. This factor was considered to play a part in the failure of many aquaculture projects in Asia.

229. It has also been suggested (UNDP/Norway/FAO, 1987) that international efforts to assist countries in the preparation of national aquaculture development plans proved to be problematical due to: (i) a preoccupation with what is technically possible rather than with what is economically feasible and socially acceptable, (ii) too few and isolated efforts in plan preparation, and (iii) insufficient linkage with a national aquaculture policy. It was further stated that international assistance in the formulation of national aquaculture policies could have been possibly more effective if the assistance had been extended over a longer term and there had been access to decision-makers at a level higher than those responsible for aquaculture or fisheries.

Towards a more sustainable development of coastal aquaculture

230. Preliminary guidelines and strategies on improved planning and management of aquaculture development are available (see, for example, Maine and Nash, 1987; ADCP, 1989; Pillay, 1990). Many countries continue efforts to enhance their capacity for planning and management of the aquaculture sector. It is, however, emphasized here that sectoral development efforts be guided by the principle of sustainable development, which is defined by FAO (1988) as:

"Sustainable development is the management and conservation of the natural resource base and the orientation of technological and institutional change in such a manner as to ensure the attainment and continued satisfaction of human needs for present and future generations. Such sustainable development (in the agriculture, forestry and fisheries sectors) conserves land, water, plant and animal genetic resources, is environmentally non-degrading, technically appropriate, economically viable and socially acceptable."

6.4.1 Coastal aquaculture in national economic development

231. In many countries, the success of coastal aquaculture development will depend on the degree of prioritization and integration in national plans for economic and agricultural development. Likewise, the success of coastal aquaculture development plans will be determined by the degree of compatibility with development plans for other sectors. Taking the aquaculture practices as relevant for the achievement of sustainable agriculture and rural development (SARD), the following elements of a sustainability strategy are presented as identified by the FAO/Netherlands Conference on Agriculture and the Environment (FAO/Netherlands, 1991a):

(a) Creating the appropriate policy framework. Two important objectives should be aimed at:

- widening people's options so that they do not need to harm their environment;

- creating the conditions for market forces to operate efficiently, while providing for corrective measures in cases where the market cannot ensure sustainable management of natural resources.

(b) Three sector policy goals are considered essential for sustainable agriculture and rural development:

- food security by ensuring an appropriate mix of self-sufficiency and self-reliance;
- employment and income generation in rural areas;
- natural resource conservation and environmental protection.

(c) Three objectives should guide the choice of options for sustainable agriculture and rural development:

- improving efficiency
- increasing resilience and minimizing risks
- promoting diversity

(d) Four major options are considered:

- intensification through specialization
- intensification through diversification
- combining on-farm and off-farm activities (pluriactivity)
- extensive systems

232. These options are not readily applicable in many cases, and the following major adjustments and changes may be required:

- decentralization by devolving more responsibility down to local level, by providing incentives for initiatives by local communities rather than relying on "top-down" administrative mechanisms;

- allocating clear rights with regard to resource use;

- relieving pressure on natural resources by undertaking improvement, rehabilitation and conservation work so that the resources can be used more intensively; encouraging demand for products which can be produced sustainably; and improving the man/land (and water) relationship through land reform and, where desirable and feasible, encouraging transmigration;

- using technologies adapted to sustainability objectives in order to provide relief at points where the environment is under particular pressure; providing farming system packages rather than handling each problem separately; seeking solutions in information technologies, good practices and know-how rather than in ever-increasing use of external inputs and hardware.

6.4.2 Coastal aquaculture and fisheries development

233. It is most important that coastal aquaculture planning and management give special emphasis to development efforts compatible with existing and projected conditions of inland aquaculture and capture fisheries, both coastal and inland (Bailey and Skladany, 1991). Effects of coastal aquaculture development on coastal fisheries resources and on consumer acceptance and marketability, especially distribution and marketing of fishery products, must be considered and forecasted. In some cases, it may even be required to limit expansion of coastal aquaculture in order to avoid detriment to coastal fisheries resource users, such as traditional small-scale fishery communities. Selection of aquaculture sites, methods and species should take account of both employment opportunities (part-time or full-time) for fishermen and local demands for species which are not provided by capture fisheries or which are caught only in insufficient amounts.

6.4.3 Coastal aquaculture and rural development

234. Coastal aquaculture development planners should, where required, actively participate in the formulation and implementation of trans-sectoral management plans aiming at coordinated land-use and resource development in coastal areas. The allocation of resources and potential sites to aquaculture and the selection of forms of aquaculture practice should be preceded by adequate on-site surveys and evaluations. It is important that coastal aquaculture development planners and experienced aquafarmers participate in coastal surveys leading to designation of zones with the resource uses specified.

235. Economic viability and social acceptability of existing aquaculture practices may be further promoted through increased horizontal and vertical integration within local economies. Aquafarmers may stimulate acceptance and support by stakeholders of other local activities when achieving agreements, for example, on changes in patterns of land and water use and waste disposal, diversification of methods, use of agricultural by-products, promotion of the local marketing system, encouragement of locally-based processing facilities, etc.

6.4.4 Coastal aquaculture and environmental policies

236. Coastal aquaculture planning and management will, in many cases, have to take account of established national policies aiming at environmental protection. In aquaculture development plans, it should be stated how the general management framework adopted for the protection of coastal environments has been adapted to meet the specific needs and characteristics of aquaculture practices. Environmental protection requirements for aquaculture should also be integrated in development plans of other sectors. Requirements and specifications on environmental assessment and monitoring of aquaculture practices should form an integral part of an organized development plan which should also contain options for mitigation of environmental impacts. Environmentally-acceptable aquaculture practices may be prioritized in development plans. Coastal aquaculture development planners should actively participate in the formulation of environmental legislation governing aquaculture.

6.4.5 Support to coastal aquaculture and limitations of development

237. Government development strategies in support of sustainable aquaculture should give increased emphasis to environmental considerations when promoting the following aspects (Chua and Tech, 1990):

- demonstration of technical and economical feasibility of aquaculture systems with guidelines in the choice of appropriate species and culture systems and appropriate farm operating procedure;

- basic infrastructure in the aquaculture zone in terms of water supply and delivery, electricity, roads, post-harvest and marketing facilities;

- availability of credit facilities and insurance schemes for aquaculture investment;

- technical and management training for small farmers, technicians and managers;

- technology development and transfer, supported by appropriate research.

238. When formulating or modifying coastal aquaculture development plans, it may prove useful to specifically address limitations to development imposed by (i) the present state of aquaculture technology and expertise, (ii) prevailing socio-economic conditions, (iii) institutional and regulatory weaknesses, (iv) access to and availability of resources required, and (v) the current state of the coastal environment and its capacity to further assimilate effects of contamination and physical modifications.

6.5 Environmental Management Options at Farm or Project Level

239. It is emphasized that environmental management at farm level can be achieved essentially through proper planning and design, and in particular, through adequate site selection allowing for sufficient water exchange, and through rationalization in farm operation and maintenance, including adequate selection of species, suitable stocking rates, appropriate feeding regimes and careful use of aquachemicals. Constant monitoring of conditions of cultured stock, water quality, and hygienic circumstances, is required.

6.5.1 Aquaculture project formulation

240. Accurate planning is essential when formulating sustainable coastal aquaculture projects. Guidance material on aquaculture project formulation is available (Insull and Nash 1990; see also Eid 1986; FAO, 1989c). The aquaculture Development and Coordination Programme (ADCP) published general guidelines for bioprogramming and design of an aquaculture facility (Brown and Nash, 1988). An elementary checklist for coastal aquaculture projects in tropical environments is given in Annex 11. In designing and building a new aquaculture facility, especially when applying new technology untried in a particular area, it may be prudent to develop the new system in stages so as to permit any necessary changes to be easily and economically incorporated.

241. The following are ten project-oriented "principles" of sustainable development, which may help prevent environmental and developmental problems in coastal aquaculture (Brindley, 1991):

(1) Consult with villagers, farmers and all other participants. Reach agreement on both problems and solutions before taking action.

(2) Plan small-scale, flexible projects. A plan should be a blueprint, not a prison. It should be able to incorporate new information that emerges during the project.

(3) Let the people benefitting from the project make the decisions. The expert's job is to share their knowledge, not to impose it.

(4) Look for solutions that can be duplicated in the hundreds of thousands for the greatest impact on development. But the solutions must still be tailored to fit local needs.

(5) Provide education and training, particularly for young people and women, who remain the most effective agents of change because they are bound to the realities of the family's survival.

(6) Keep external inputs to a minimum to reduce dependency and increase stability. Subsidies, supplements and inappropriate technology are unsustainable.

(7) Build on what people are doing right. New ideas will be adopted only if they do not run contrary to local practice. New technologies must support existing ones, not replace them.

(8) Assess impacts of proposed changes. A multi-disciplinary team, ideally including specialists from the same culture, should look at economic, social, cultural and environmental aspects.

(9) Consider both inputs and outcomes. The failure of projects focusing on a single outcome, such as agricultural productivity, has proved that more is not always better.

(10) Maintain or improve the participants' standard of living. Long-term environmental improvements are unsustainable unless they also address the problems which the poor face today.

6.5.2 Adaptive and mitigatory measures

242. Properly sited and managed aquaculture activities should not result in unacceptable ecological change. Nevertheless, should change occur, measures can be taken to avoid or minimize it.

Rational use of mangrove wetland

243. GESAMP (1991c) recommends that the use of mangroves along the shore front or fringing river banks for aquaculture be discouraged in view of their significant contribution to coastal stability preventing soil erosion, and their role as valuable habitats. Unlike extensive shrimp farming in mangrove swamps utilizing tidal energy for water exchange and shrimp larvae supply, modern intensive shrimp farming uses mechanical pumps for water supply and seeds from hatcheries. As such the use of mangrove swamps for intensive shrimp culture cannot be justified in environmental terms. Traditional use of mangrove wetland for extensive aquaculture has minimal negative ecological impacts.

244. Burbridge et al. (1988) suggest the following approach for fish and shrimp pond construction in mangrove areas:

(1) In mangrove areas, the location of ponds inland from the mangrove should be considered as the first alternative.

(2) Rehabilitation of abandoned ponds and/or the improved management of existing ponds should also be considered before the clearance of additional mangrove areas is envisaged.

(3) Where there is no alternative to the conversion of mangrove, the following guidelines should be observed:

(a) avoid soils with high acid-sulphate potential;

(b) if this is unavoidable, incorporate into the pond design the ability to exchange approximately 25 percent of the pond water volume daily by either tidal exchange or pumping;

(c) if adequate exchange cannot be achieved, lime should be used to neutralize acids, or non-acid soils brought to the site to form the bunds and to line the ponds;

(d) do not site the ponds over tidal creeks because they are believed to form the primary habitat for the post-larval stage of several fish species normally cultivated in ponds; the creek beds also form poor foundations for bunds and slumping is likely to result;

(e) do not block tidal creeks and other channels which allow tidal flushing of adjacent mangrove;

(f) avoid the diversion of freshwater runoff away from the mangrove; where freshwater has to be diverted, it should be redirected to the mangrove by means of shallow channels along seaward margins of the ponds.

245. Kapetsky (1987a) emphasizes the need for long-term integrated management of mangrove areas. Frequently proposed remedies such as the intensification of pond culture in place of extensification, and the promotion of non-destructive aquaculture techniques such as pen, cage and raft culture as alternatives to pond culture, are often not acceptable because of technological end economic constraints. Thorhaug (1987; 1990; see also Coats and Williams, 1990) has reviewed methods and results of mangrove and seagrass restoration as a means to benefit fisheries and aquaculture, both ecologically and economically.

Waste management

246. Treatment of effluents may be required, particularly in intensive aquaculture systems. However, high volumetric flow rates and relatively dilute concentrations of contaminants in such effluents pose significant problems. Treatment technologies are being developed in industrialized countries based on sedimentation, decantation, biological oxidation and filtration (Warrer-Hansen, 1982; see also Petit and Maurel, 1983). Often, these techniques are designed for "high-tech" systems (see for example Mäkinen et al., 1988; Cripps, in press; Beveridge et al., 1991; Dryden, 1991). Huguenin and Colt (1989) review water-recycling approaches, including nitrification and biofilters, foam fractionation, carbon adsorption, ion exchange, algal systems and ozone.

247. Economic constraints in production and operating costs often make the treatment of farm wastes difficult to support (Muir, 1982), particularly in developing countries. Treatment facilities must be efficient, yet economically feasible to install and to operate. However, use of suitably designed sedimentation ponds appears to be a cost-efficient practice in many commercial farms. Whilst sedimentation methods are generally effective for the removal of suspended solids (Henderson and Bromage, 1988), the process itself may increase the rate of release of dissolved substances during solids decomposition (NCC, 1989). The sludge accumulated in sedimentation ponds or in culture ponds should be deposited on land on mud bunds of the ponds.

248. Removal of suspended matter from ponds may also be achieved in sedimentation ponds stocked with filter-feeding organisms, such as oysters or mussels. Nutrient loads can be reduced when seaweeds such as Gracilaria and Caulerpa are polycultured with shrimp or milkfish in ponds or cultivated in exit canals (Chua, in press). Integrated practices, for example, off-bottom polyculture of bivalves and seaweeds (Ruying and Qingyin, 1992), salmonid cage culture combined with mussel culture (Folke and Kautsky, 1989), use of mullets in bottom cages underneath seabream cages (Porter et al., in press), or shrimp/oyster co-production systems (Wang, 1990) may prove very successful in reducing effects of waste loads from sea-based farms (see also Shpigel and Fridman, 1990).

249. Changing culture sites is an approach which may be used with sea-based aquafarms to avoid excessive accumulation of organic sediments. Site rotation may contribute to sediment recovery through natural dispersal and disintegration of wastes during periods where farming areas are left to lie fallow. Additional trawling of sediments is sometimes applied to assist oxygenation and mineralization of wastes. Sediment loadings per unit area may be reduced through single point mooring systems in cage farms (Ives, 1989).

250. Sophisticated technology, such as submersible pumps and mixers, and funnel-shaped waste catchment devices or collectors, is being experimented which perhaps may be used regularly in the future to collect or disperse organic wastes deposited (NCC, 1989; Weston, 1991).

251. Implementation of approaches such as site rotation and dispersal of sedimented waste may, however, appear undesirable in certain cases, since these practices may only result in the disturbance of a greater area of the bottom (Gowen et al., 1990; Weston, 1991).

Rational use of feeds and fertilizers

252. Since inputs of fertilizers and, in particular, feeds are often the main cause of deterioration of environmental quality within and outside the culture unit, improvements are required in the management (i.e., choice, storage, handling and application) of these inputs. The reader is referred to existing relevant documentation such as, for example, Tacon (1988); New (1987); Tacon (1987a, 1987b). It is emphasized that the choice and adoption of appropriate "low-pollution" feeding methods and feeds will, in many cases, be governed by financial circumstances aquafarmers are facing.

253. Excessive use of inorganic and organic fertilizers should be avoided. Under farm conditions, it is difficult to precisely predict or adjust the degree of fertilization required. Monitoring of pond water quality should be carried out regularly. It is suggested to record time, frequency and mode of application as well as the type and amount of fertilizers applied. It should be ensured that fertilizers be well dispersed or diluted. Piedrahita and Giovannini (1991) discuss new developments in the engineering and management of fertilized non-fed pond systems.

254. Unfortunately, to date there is little or no information on the dietary nutrient requirements of warmwater fish or shrimp species under semi-intensive pond farming conditions, or concerning the natural food productivity of ponds with different management (i.e., water, aeration, fertilizer and feed) techniques (Tacon, in press). However, direct transfer and application of intensive complete diet feeding strategies to semi-intensive pond farming systems is current practice. For example, at present almost all commercial shrimp farmers in Latin America and Asia employ a complete diet feeding strategy for their semi-intensive shrimp ponds with no provision within the artificial diets used for natural food availability (Tacon, in press). Clearly, this situation must be remedied if farmers are to reduce both production costs and feed-derived waste loadings to the environment.

255. It cannot be over-emphasized that feeding regimes need to be adapted to specific feeding habits and behaviour of cultured species, particularly in intensive (feed-lot) farming systems. Ideally, feed inputs should be determined based on knowledge of species-specific feeding behaviour and nutritional requirements as well as on estimates of biomass in the culture units. However, calculation of optimum feeding rates is problematic since appropriate methods to accurately assess exact weight and number of stock per culture unit still need to be developed.

256. In many cases, feed wastage due to over-feeding can be reduced by careful hand-feeding. Feed supply by automatic feeders should be closely monitored. It may be required that feeds be evenly dispersed over the culture unit, or feeding strategy may have to be adjusted according to territorial behaviour of cultured stock or water currents prevailing in the culture unit.

257. Meticulous recording is suggested of amount and type (e.g., trash fish, compound feeds, water content, chemical composition, particle size, etc.) of feeds given, of feeding methods and devices (hand-feeding, demand/automatic feeders, boat feeding, feed blowers, etc.) as well as of feeding time and frequency per day or of any change in feeding strategy, such as position of operator/feeder as related to the culture unit. Feeding response of cultured stock should, where possible, also be observed. With this information recorded, the significance of farm-specific food conversion ratio (FCR) values may be increased as the parameter relevant for assessment of feeding efficiency.

258. Feed losses in salmonid cage culture have been reduced by the use of slow sinking feed pellets and, more recently in Scandinavia, by the introduction of floating pellets which are released from the base of the cages and float slowly to the surface (NCC, 1989). These floating pellets allow feed wastage to be monitored and uneaten pellets to be removed. Such techniques, which aim at maximizing the opportunity for ingestion of pellets, are still very much at the development stage, but may have potential for significantly reducing solid loadings. However, dispersal by currents of uncaptured pellets over wider areas may be considered advantageous or disadvantageous for the environment. As related to the water content of pellets. NCC (1989) recommends that the use of moist or wet diets be discouraged in Scottish salmonid culture.

259. Currently, increasing attention is also being directed to reducing waste output through development of nutritional strategies aiming at improved composition of feeds for intensive aquaculture as carried out in temperate countries. These strategies include the application of biotechnology to pre-processing of feed ingredients to increase digestibility and aim at attaining optimal nutrient and energy balance in the diet thereby leading to high nutrient retention. Cho et al. (1991) state that diets which are highly digestible, of high nutrient density and with a well-balanced protein: energy ratio are the most desirable feed. However, it is also stated, that feed cost per unit of fish production must, at the same time, be acceptable to the market place. An overview on current discussions and experiences related to improved feed formulation and processing for intensive aquaculture in temperate countries can be found in Cowey and Cho (1991). The reader is further referred to Akiyama (1991); Jensen (1991); Enell and Ackefors (1991); Carter (1991); Seymour and Bergheim (1991); Clarke (1990); New (1990b. 1989).

Chemical usage

260. Aquaculture chemicals including biocides and biostats, chemicals in construction materials, etc., should be used with extreme care. With environmental awareness growing worldwide, it can be expected that the issue of chemical usage in aquaculture will become a very significant criterion influencing consumer acceptance and marketability of aquaculture products.

261. Farmers should be encouraged to reduce, as far as possible, all treatments required through the use of sound husbandry practices aiming at stress prevention, including careful minimal handling and, in particular, avoidance of over-stocking (NCC, 1989). More emphasis should be given to preventive measures, especially in intensive culture systems. Use of chemicals should be considered as the last tool when other measures have proven inadequate.

262. Prevention of diseases should, wherever possible, include strict quality control of stocking material; proper storage, handling and application of feeds; regular water-quality monitoring and inspection of species; early detection of unusual behaviuor, loss of appetite, etc. and segregation or removal of any sick or dead farmed organism. Biological control methods, such as the use of wrasse species (Ctenolabrus spp.) to remove lice parasites on Norwegian salmon, may help to reduce application of hazardous chemicals (Anonymus, 1990).

263. Prophylactic use of antibiotics should be avoided and antibiotics should be administered only for the purpose of curing infectious disease (ADB/NACA, 1991; Braaten and Hektoen, 1991). The environmental risks involved may be reduced by limiting exposure to specific drugs, through, for example, modified formulations, avoidance of frequent use of a single compound, rotation of drugs, changes in application methods, and due timing of applications.

264. For proper aquaculture drug use in Canada, it has been recommended (Johnson and Ronnie, 1989, quoted in Schnick, 1991) that the aquafarmer (1) obtain an accurate diagnosis, (2) use an appropriate compound and route of administration, (3) use doses for the minimum time, (4) keep records and evaluate treatments, and (5) be aware of residues. Evidently, specialized expertise is required to assist aquafarmers in the diagnosis of disease problems, in improved disease-preventing farm operation and appropriate use of drugs.

265. It may be desirable to establish public aquaculture health management services which may cover requirements for quarantine, diagnosis, treatment, monitoring and product quality control. It should be ensured that related efforts also benefit small-scale aquafarmers, for example, through training and extension.

266. Farmers should keep records on chemical usage, including type, amount and combinations of chemicals used; reasons for application; mode, frequency, start and end of administrations; amount/number and sizes of stock treated; and time of harvesting of treated stock. Safe storage and disposal of chemicals are essential.

267. Ideally, detailed inventories of chemicals used should be established for use by designated authorities. Registration, marketing licences and other control requirements may be imposed on those importing, manufacturing, processing (e.g., feed producers) or selling hazardous compounds. Aquafarmers buying produce containing potentially hazardous compounds should be provided with understandable information for appropriate use including warning statements, contra-indications for use, dosage recommendations, treatment procedures, drug retention times, recommended withdrawal times, etc. The reader is further referred to FAO/WHO, 1991a; ICES, 1990; Bernoth, 1991b; Ellis, 1991; Meyer and Schnick, 1989; Schnick et al., 1989; Williams and Lightner, 1988.


268. It is due to the capacity of bivalves to concentrate and accumulate pathogenic microorganisms and chemical substances from polluted waters, coupled with the tradition of consuming shellfish raw or only lightly cooked, that bivalve molluscs present a risk for the unwary consumer.

269. Several measures are being implemented or tested to prevent related human health problems (Canzonier, 1988; Thrower, 1990). Documentation on experiences with depuration and sanitation of shellfish in developing and industrialized countries can be found in NACA (1989) and Otwell et al. (1991).

270. Methods of post-harvest heat treatment of bivalves, ranging from steam blanching to full sterilization in processes such as canning, are appropriate only for bivalves which contain heat labile contaminants and which are acceptable by the consumer as cooked products. Application of several marinading solutions may help to wash off bacteria and clay particles holding heavy metals from the gills and feeding palps. Irradiation techniques, though costly, may be used to sterilize products, but may result in undesirable changes in flavour, odour and texture.

271. Relaying is the harvesting of the shellfish from a contaminated site and allowing them to purge themselves of contaminants in unpolluted waters for relatively long periods. This practice, which may indeed achieve effective removal of some contaminants such as heavy metals, is, however, time- and labor-intensive.

272. In depuration processes, the animals are transferred to special tanks with constant or frequent exchange of clean seawater whereupon pathogens are supposedly eliminated. The efficacy/duration of the process is quite variable, depending on the nature of the contaminant, the species being depurated, the metabolic rate of the species, and the water quality in the tank.

273. Without adequate disinfection systems, depuration may serve to spread pathogens from a few contaminated animals to many others in the depuration system. Seawater is therefore often sterilized by using chlorine, ozone or ultraviolet light. However, high levels of chlorine may well inactivate many pathogens but may also adversely affect the animals. With some disinfectants, the animals close up, and, therefore, do not depurate. Although costly, ozonation appears to be an effective method. Moreover, residual ozone in the water, which does not adversely affect the filter-feeders, results in the inactivation of bacterial fish pathogens, certain parasites and, possibly, viruses, including poliovirus (GESAMP, 1991c). Controversy still rages over whether or not depuration will remove pathogenic viruses (Thrower, 1990). Use of ultraviolet light is most widely used, and has the advantage of relative low costs and the absence of residual taints and odours from chemical residuals (Thrower, 1990).

274. However, depuration on a small-scale is not economically feasible, and may require a collaborative operation by aquafarmers and processing industry, possibly supported by public authorities. The use of the process also imposes severe time restraints in marketing procedures and may require the application of stringent control measures in the handling and distribution of the depurated product. Canzonier (1988) emphasizes that operational requirements for effective depuration are so onerous that they are frequently either circumvented or the process is abandoned altogether.

275. Other types of contaminants such as certain hydrocarbons, heavy metals and biotoxins, may be so avidly sequestered in the tissues of the bivalve that the depuration process is virtually useless in reducing them to acceptable levels. Shumway (1990, 1989) reviewed attempts to detoxify shellfish contaminated with phycotoxins aiming at reducing the duration of "off-market" times. While relaying is satisfactory for many species, toxin retention times vary considerably between species, and some species remain toxic for extended periods. Ozonation may prove effective in some cases, while it is useless in detoxifying bivalves that have ingested algal cysts or have had the toxins bound in their tissues over longer periods. At present, the economic feasibility of efficiently detoxifying shellfish on a large scale basis in artificial systems is not promising (Shumway, 1990).

276. In Japan and other countries, application of chemicals such as peroxocarbonate, cupric sulphate, formalin and others, is being considered to remove red tide organisms (Okaichi, 1991). Even though the use of such chemicals may be restricted to aquaculture ponds or very limited water areas, ecological and economic feasibility of this type of countermeasure remains to be thoroughly assessed. In view of the increasing number of algal bloom events, Maclean (1991) emphasizes the need for monitoring of shellfish and/or plankton combined with hydrographic research as well as public education.

277. Algal bloom countermeasures at farm level may include (Black, 1988): (i) provision of multiple water intakes (e.g., pumping of plankton-free water from various depths); (ii) vertical movement of cultured organisms (e.g., sinking of cages); (iii) relocating of culture units to unaffected areas which requires detachable moorings and towable structures; (iv) pre-emptive harvesting; (v) reduction of food supply and stress to lower metabolism of cultured stock; (vi) on-site shielding of stock (e.g., bubble curtains, injection of clear water, non-porous barriers); (vii) cortisone treatment to reduce gill-swelling.

278. In concluding, it appears that efforts directed at decontamination of aquaculture produce may, in many cases, be the second best option to cope with problems related to coastal water pollution and algal bloom events. Aquaculture production in unpolluted waters and low risk areas combined with effective hazard assessment and regular monitoring should be promoted. Public awareness programmes may urge consumers to eat only cooked seafood without entrails and gills, specifying periods and species for safe consumption. Unfortunately, in some cases, it may be necessary to enforce temporary bans on harvesting, transporting and marketing of possibly contaminated shellfish.

Previous Page Top of Page Next Page