Sustainable growth and expansion of aquaculture: an ecosystem approach

The Fish Site
by The Fish Site
1 April 2007, at 1:00am

By Food and Agriculture Organization of the United Nations (FAO) and extracted from The State of World Fisheries and Aquaculture 2006

The state of World Fisheries and Aquaculture 2006


The outlook for the Code’s implementation remains mixed in many countries even though there are strong indications that it is taking root in many of them and guiding efforts in the management and use of fisheries. Developing countries face a suite of constraints that impede governance and inhibit their capacity to implement the Code. All countries, irrespective of their level of development, are grappling with the implementation of new approaches to the management of fisheries. Conceptually, these approaches are readily elaborated and understood but constraints are encountered when action is required to put them into practice.

The need for ongoing capacity building and institutional strengthening, taking into account the difficulties and needs identified by developing countries, is critical if further progress is to be achieved. Efforts to build on past outcomes by broadening and deepening implementation are required. Countries will continue to be strained as they seek to implement the considerable number of international fisheries instruments concluded since UNCED, especially in fulfilling the obligations they have assumed through the acceptance of some of these instruments.

The logistical aspects of promoting “inclusive” approaches to fisheries, as envisaged in the Code, are proving to be a challenge for many countries and greater efforts should be devoted to achieving higher levels of participation in decision-making. In many countries, participatory approaches to fisheries are new, requiring fundamental adjustments in both thinking and organization. Coupled with broader stakeholder participation is the need to promote greater accountability among stakeholders.

Maintaining momentum to support the Code’s implementation is an ongoing issue for many countries. In the face of limited capacity and stressed by the workload, many fisheries administrations are buckling under the strain. This stress is also highlighting and exacerbating other administrative shortcomings that impede implementation. This situation points to the need for countries to continue monitoring their progress with regard to implementation and to take remedial action to the extent that their resources and capacities permit.

The Issue

Aquaculture has a long tradition in some parts of the world, and many examples of well-integrated aquaculture systems can be found throughout mainland Asia and in the Pacific Islands. In the past, these activities were generally limited in impact owing to their small scale and their low-input nature. The systems were reliant on locally produced inputs, often within the larger farming system. With the progressive development of aquaculture as a commercial enterprise capable of generating significant income at household or business levels, these linkages have tended to be broken. Even in less-developed economies (such as certain countries in Africa) where aquaculture was introduced some decades ago as a low-investment subsistence alternative, today’s production is increasingly aimed at satisfying market demands rather than supplying fish for household needs.

Commercial aquaculture development invariably involves the expansion of cultivated areas, higher density of aquaculture installations and the use of feed resources produced outside the immediate area. With more intensive production methods there are also tendencies to introduce alien species, use more intensive formulated feed regimes and, in some systems, administer chemicals for the control or management of diseases. All these practices can have an aggregated effect at the ecosystem level and compromise its overall integrity.

Common effects of many aquaculture practices on the ecosystem may include any of the following:

  • increasing demands on fisheries for fishmeal/oil, which are major constituents of carnivorous/omnivorous species feeds;

  • nutrient and organic enrichment of recipient waters resulting in a build-up of anoxic sediments;

  • changes in benthic communities;

  • eutrophication of lakes or coastal zones;

  • disruption, and sometimes permanent restructuring, of biological and/or social environments;

  • competition for, and in some cases, depletion of resources (e.g. water);

  • negative effects from escaped farmed organisms.

The large-scale (extensive and/or intensive) development of shrimp culture in some areas has resulted in the degradation of wetlands and mangroves, and has also caused water pollution and salinization of land and freshwater aquifers. The misapplication of chemicals, the collection of seed from the wild and the introduction of alien species have also caused concern in some locations. Even intensive aquaculture practices that do not require external feeds, such as mollusc culture, can under certain conditions produce local anoxia of bottom sediments and increased sedimentation. Expansion of commercial aquaculture has also led to instances of negative interaction with coastal small-scale fisheries, when there is competition for space with fishers and/or when escaped fish or environmental deterioration negatively affects fisheries. Some of these effects can indeed “jeopardize the options for future generations to benefit from the full range of goods and services provided by ecosystems”.

As is the case in most food production systems, aquaculture has, or can have, negative impacts. These must be kept within socially acceptable limits.5 The inadequate environmental management of (intensive or extensive) aquaculture is an issue that needs to be taken seriously. Letting aquaculture development proceed irresponsibly or taking only partial approaches to its management incurs a risk that the negative impacts may counteract any benefits from aquaculture or that it will not produce the expected benefits. In the long term, aquaculture may fail to provide the additional fish supplies needed to meet the demands of a growing world population.

Nevertheless, aquaculture itself is also subject to the negative impacts of anthropogenic factors such as contamination of feed and of aquatic environments by urban waste and agricultural pollution, and landscape mismanagement. These factors limit the scope and nature of aquaculture development in some regions of the world.

Possible Solutions

The conventional approaches

It is not surprising, perhaps, that attempts to deal with the negative impacts of aquaculture have taken many forms. On the one hand, those responsible for governing the sector have developed broad principles (e.g. the Earth Summit) and codes of conduct (e.g. the Code of Conduct for Responsible Fisheries). On the other hand, those who are asked to harmonize the expectations of aquaculture entrepreneurs with the exigencies of the ecosystem often have recourse to control and command strategies (e.g. licences, standards for feed, use of pharmaceuticals).


In an attempt to control inadequate developments, countries worldwide have implemented a large number of aquaculture regulations. These have varied from the general – for example, banning of mangrove utilization for aquaculture practices – to the very specific – for example, determining maximum production per area, rules for disease control, and use of drugs.

However, these regulations – neither on their own nor taken together – do not provide a comprehensive framework for ensuring the sustainable use of aquatic environments. That will happen only when aquafarming is treated as an integral process within the ecosystem.

Advances in technology have made production more efficient and have facilitated intensification. Yet the regulations in place cannot guarantee sustainability, especially as most of them focus on the individual farmer and do not consider the additive (cumulative) or synergistic effects of multiple farms on a particular area. At the same time, farmers’ economic appraisals tend to have a narrow (short-term) view, focused on the more immediate production results. Such appraisals do not include the mediumand long-term revenues and costs that may be imposed on the farming activity itself and on the rest of the society in the form of a reduced supply of ecosystem goods and services.

Moreover, and equally important, the regulatory structure for aquaculture often does not allow, or facilitate, a production mode or approach that is conducive to a balanced ecosystem. Nutrient cycling and reutilization of wastes by other forms of aquaculture (polyculture) or local fisheries are frequently prohibited or discouraged.

Decision-making tools

Environmental impact assessment7 (EIA), in its various forms, is possibly the most common tool in use. EIA has been used worldwide by those in charge of controlling the impact of all kinds of human activities that are potentially damaging for the environment, including commercial aquaculture. A typical EIA considers the positive as well as negative aspects of the activity, whether direct or indirect, and of an environmental, social and economic nature. However, as employed, the EIA usually does not take into account other kinds of impact that are relevant for aquaculture. Frequently it is activity-oriented, even farmer-oriented, but does not consider strategic or integrated planning.

A wide range of EIA and monitoring procedures are currently employed worldwide and some of them are well adapted for use with aquaculture proposals and activities. Yet in many other cases such procedures are simply not used, not sufficiently developed, or are well known but not implemented. Also, they may be inadequately designed inasmuch as they are not capable of providing key information on changes in the ecological features of the specific environments that sustain – or are proposed to sustain – given aquaculture practices.8 A major drawback of EIAs is that they usually cannot be applied to existing aquaculture enterprises because they do not provide the detailed information necessary to apply remedial measures for any harm already done to the environment.

A further problem is that EIAs alone do not ensure a sufficiently coherent view of the ecosystem. Frequently, where aquaculture is practised there are also, inter alia, agriculture, industrial or urban development and tourism. These all use common resources (e.g. coastal areas, water), yet in many cases each is evaluated independently without considering the future likely development of other users and of the combined effect on the ecosystem. Likewise, EIAs often fail to take into account the human and social aspects of the target activity, in particular with regard to the poorest segments of society.

The ecosystem approach to aquaculture

The mandate

The concern about the impact of human development on the ecosystem goes back several centuries. Recently, the 1992 Earth Summit in Rio de Janeiro, Brazil, concluded that environmental management policies, often developed for one sector without much regard to other sectors, were not adequately covering the full impacts of human development and exploitation on the environment. Following the summit there was a concerted move to develop and apply a more holistic approach to policy decisionmaking with regard to sustainable development. This included a more ecosystemic approach to development and management.

The first principle for an ecosystem approach, as described by the Convention on Biological Diversity (CBD), is that the objectives of management of land, water and living resources are matters of societal choice. But, this novel approach to management of natural resources also implies focusing on changing human behaviour and attitudes towards the use of natural resources.

In 1995, the Code of Conduct for Responsible Fisheries was adopted by the FAO Conference. The Code also deals with aquaculture more specifically through Article 9, addressing many aspects relevant for its sustainable development.

All of the above amount to an implicit recognition by those concerned that a number of potential impediments to continued growth and intensification of aquaculture must be overcome, if this activity is to conform to the growing expectations of society for ecologically sustainable development (ESD).11 The ecosystem approach to aquaculture will indeed be the way to overcome these impediments and can serve as the ESD implementation framework that is essential to satisfy the conceptual objectives of UNCED, WSSD, CBD and other international instruments.

The implications

An agreed definition of the ecosystem approach to fisheries (EAF) already exists. The ecosystem approach to aquaculture can be modelled on this definition, as follows:

An ecosystem approach to aquaculture (EAA) strives to balance diverse societal objectives, by taking account of the knowledge and uncertainties of biotic, abiotic and human components of ecosystems including their interactions, flows and processes and applying an integrated approach to aquaculture within ecologically and operationally meaningful boundaries. The purpose of EAA should be to plan, develop and manage the sector in a manner that addresses the multiple needs and desires of societies, without jeopardizing the options for future generations to benefit from the full range of goods and services provided by aquatic ecosystems.

This definition implies the need to use proper instruments, processes and structures to deal effectively with issues of an environmental, social, technical, economic and political nature. Following the principles of the EAF and ESD, the EAA should have three main objectives within a hierarchical tree framework: i) human well-being, ii) ecological well-being and iii) the ability to achieve both, i.e. effective governance.

The EAA framework can be developed and applied/used at least at the scales or levels described below, but with the requirement to provide adequate norms and regulations for each level.

At the farm level with the implementation of sound EIA or similar decision-making tools (i.e. those that ensure proper consideration of, and accounting for, ecosystem effects of the proposed activity) for new aquaculture activities and the development of retrospective impact assessment and mitigation tools for activities that already exist. At this level, some of the relevant decisions to be made with an ecosystem perspective are site selection, production level, species to be used (exotic versus native), farming systems and technologies and, very important, the socio-economic effects at the local level. Likewise, improved management practices are usually implemented and followed up at the farm level.

At the proper geographical scale. This can vary and consist of, for example, the watershed, the coastal zone, the offshore marine area or the biogeographical region where aquaculture activities take place. The application of strategic planning and management guidelines and tools should promote the development of human societies around integrated and sustainable aquaculture. Issues such as escapees, disease transmission, contamination from and to aquaculture, competition for land and water use will be relevant at this level. Likewise, the implications for human well-being are highly relevant at this geographical scale, for example regarding job availability, rural development, consideration of indigenous communities and gender issues. The latter aspects need to be considered within existing scenarios and alternative projects for human development in the area.

While the EAA should be the responsibility of aquaculture agencies, its full implementation will require collaboration with, and cooperation from, agencies responsible for managing other activities that have an impact on the aquatic ecosystem (e.g. capture fisheries administration, coastal zone development bodies, watershed management organizations, agriculture, forestry, industrial development). The design of aquaculture management zones could be a relevant tool, particularly when including the benefits of integrated multitrophic aquaculture15/polyculture or integrated aquaculture–fisheries initiatives. Such approaches can also be relevant at the farm level. Further important aspects, at both farm and regional levels, are anthropogenic impacts on aquaculture and the need for increased protection from such impacts.

At the industry level. At this broader level the EAA should apply where issues such as availability of raw material (in particular fish) for feed manufacture and broader ecosystem impacts on fisheries and agriculture resources need to be considered. Tools such as lifecycle assessment (LCA) of aquaculture commodities could be useful at this level. Other relevant issues include those relating to markets and marketing, employment and salaries, and social opportunities for the region and the country.

Recent Developments

A good model for practical implementation of EAA can be found in Australia, were an ESD approach to aquaculture has been developed and is being implemented. The approach combines analytical and participatory methods and aims to achieve ecosystem and human well-being through effective governance.

A relevant step towards EAA was provided by GESAMP in 2001 when it published its guidelines and tools for the planning and management of coastal aquaculture development. The planning process proposed uses EIA but within a broader framework that considers the integration of aquaculture with other coastal activities and assesses costs and benefits in a more comprehensive manner.

Several research initiatives focusing on a more ecosystemic approach to aquaculture are currently in progress, such as the ECASA project in the Mediterranean Sea, which is facilitating the adoption of the EAA in this region.

Even though the EAA is still at a very early stage of development, relevant lessons can be drawn from its application within the ESD framework as well as from experiences and knowledge obtained from freshwater integrated fish farming and coastal polyculture systems (e.g. fish and mussels, fish and seaweeds). These experiences derive from the sustainable use of ecosystems through enhancing or combining aquaculture activities with other activities, such as fisheries (e.g. aquaculture-based fisheries) and agriculture (e.g. rice–fish farming). These culture systems contribute positively to environmental improvement by recycling nutrients and organic matter through integrated farming systems. Integrated aquaculture–agriculture practices have shown how rice–fish culture can help farmers reduce the use of environmentally damaging pesticides, while fish culture naturally improves the fertilization of rice fields, protein production and economic viability. Wastewater-fed freshwater aquaculture and coastal mollusc and seaweed farming can be used to recover excess nutrients, thereby reducing risks of eutrophication and other negative effects. These technologies and management approaches can also be considered as important mitigation strategies to be applied in existing farms for which no appropriate planning was done or for which EIA types of tools were not used, or were used improperly.

Considering consumers’ increasing awareness of environmental and food safety issues, some farmers and (more often) farmers’ associations/consortia have adopted a variety of standards and labels, most of which are specifically intended to allay consumers’ concerns about negative environmental consequences. Examples of such labels are the “better management practices”, clean production agreements, “principles of responsible aquaculture”, and certification and ecolabelling schemes. Certain portions of the industry, at least, in different countries and regions, are becoming more aware and better prepared to adopt a full EAA.

Other key aspects to be considered when implementing an EAA include the following.

Risk analysis

“Risk” has been defined as “a combination of the severity of consequences and likelihood of occurrence of undesired outcomes”, and “hazard” as “the presence of a material or condition that has the potential for causing loss or harm”. No matter how well managed a system is, there will always be associated hazards and risks. The process of risk analysis is driven by multiple objectives for resource protection as embodied in a number of international agreements and responsibilities. The principal components of a risk analysis process are illustrated below.

When applying any risk analysis, all people at risk should be included. Civil society dialogue and public–private partnerships should be promoted. The use and dissemination of reliable scientific information should be an integral part of risk management. At the national level, enabling legal and policy environments that support the application of risk assessments and management measures should be promoted. In order to understand more clearly the risks, hazards and vulnerabilities; to develop methods to assess them as well as study the connections between the different risk events and patterns; and to identify integrated approaches to risk management, awareness raising and capacity building will be necessary and should be treated as matters of priority, especially for developing countries.

Key challenges in applying risk analysis to aquaculture are the inadequacy of scientific information, both in terms of quality and quantity, and the lack of appropriate methodology.

Alien species in fisheries and aquaculture

The ecosystem approach, as defined by the Convention on Biological Diversity, recognizes that the decision to develop, use or conserve resources will be a matter of societal choice and the sovereign rights of governments. One aspect of these choices concerns the use or not of alien species. Wise choices will depend on accurate information.

Article 9.2.4 of the Code of Conduct for Responsible Fisheries recommends that “States should establish … databases … to collect, share, and disseminate data …” The FAO Database on Introductions of Aquatic Species (DIAS) contains over 4 000 records of introductions of fish, molluscs, crustaceans, aquatic plants and other aquatic organisms.

The information in DIAS is incomplete, however. This mostly reflects the fact that concerned authorities have not monitored and evaluated past introductions. Monitoring and evaluation of the use of alien species in fisheries and aquaculture need to be improved and preferably should include analysis of both environmental and socio-economic impacts.

Analysis of the information contained in DIAS revealed that the ten species most often introduced include omnivores, herbivores and carnivores, as listed below ranked from most to least common:

  1. Common carp (Cyprinus carpio)
  2. Rainbow trout (Oncorhynchus mykiss)
  3. Mozambique tilapia (Oreochromis mossambica)
  4. Silver carp (Hypophthalmichthys molitrix)
  5. Grass carp (Ctenopharygodon idella)
  6. Nile tilapia (Tilapia nilotica)
  7. Large-mouth bass (Micropterus salmoides)
  8. Mosquito fish (Gambusia affinis)
  9. Big head carp (Aristichthys nobilis)
  10. Goldfish (Carassius auratus)

Aquaculture was the main reason for the deliberate movement of aquatic species across national borders (see Figure).

Although DIAS does contain reports on the impacts of alien species, the information is incomplete and indicates that improved monitoring and assessment are needed. Impacts of introduced species fall into two broad categories: ecological, which includes biological and genetic effects, and socio-economic effects. However, these two categories are not independent and socio-economic changes brought about by alien species can, in turn, cause further ecological changes. Although records in DIAS indicate that there are more positive social and economic benefits than negative impacts from the use of alien species, adverse impacts can be serious.

  • There is a need to define relevant policies and regulations at the farm, regional, subsectoral and sectoral levels that focus more clearly on aquaculture as an integral means for human development. This implies involving the farmers and the private sector in decision-making (implementing the ecosystem approach with all stakeholders), which may require clarifying the costs and benefits of an EAA as well as defining rights and duties at all levels. The EAA may not be implemented successfully if it is not fully understood and adopted by the industry and the individual farmers. It may also be necessary to create economic and other incentives for an EAA. In general, an EAA can be a powerful pathway to meeting ecocertification requirements as well as the broader objectives of food security and safety. It can favour the joint certification of fish production clusters (e.g. aquaculture clusters or fisheries/aquaculture clusters).

  • The future of the EAA will be highly dependent on government actions. As is usual when implementing sustainable development-related approaches, the capacitybuilding process in research, administration and industry will be a crucial element.

  • Within the EAA, the economic evaluation of projects (including externalities) will become essential for decision-making. Tools and comparative approaches are becoming available that will facilitate such evaluations.

  • Relevant tools will include proper research to understand the implications for the ecosystem of different aquaculture practices and to define the risks both from and to aquaculture, and the application of risk analysis in aquaculture.

  • There will be a need to facilitate an operational definition of ecosystem boundaries for management, for example to assess carrying capacity or water-management needs and to clarify administrative and legal jurisdictions. This will require the use of different tools and methodologies (e.g. geographic information system tools). However, defining the ecosystem boundaries and evaluating their implications could be very challenging, for example when addressing the ecosystem boundary effects of the use of fishmeal or other feeds such as soybean.

Negative environmental impacts, which are not always immediately obvious, have included loss in native biodiversity from:

  • direct ecological interactions such as predation and competition;

  • genetic contamination when alien species breed with local strains or species;

  • disease transmission when alien species bring in new pathogens;

  • habitat alteration.

Negative economic impacts may arise when the biodiversity that is affected supports agriculture or fisheries. An example of this is the introduction of the golden apple snail into 15 countries, mostly in Asia, in the hope of developing an export industry. However, none of these 15 countries has reported snail exports and, instead, rice farmers in these countries have suffered as the snail consumes large quantities of paddy (rice). Other examples include the European crayfish and European oyster industries that were destroyed by pathogens that accompanied crayfish and oysters imported from North America.

There are benefits to the use of alien species, however. Agriculture provides a clear example – most of the world’s agriculture is based on animal and plant species grown outside their natural range. Such benefits can also be obtained in aquaculture. Chile introduced Pacific and Atlantic salmon in the 1970s and is now the world’s leader in farmed salmon production. The oyster industry in Europe is now based on the Pacific oyster. Tilapia, a group of species originating in Africa, is cultured worldwide and provides income and high-quality protein to many rural areas. Tilapia production in Asia is increasing both in farms and in culture-based fisheries, and many of these farmers and fishers are in the lower income classes.

Further Information

To view the previous articles by FAO;
Fishers and Fish Farmers, please click here

Aquaculture Production, please click here

To view further articles from The State of World Fisheries and Aquaculture 2006, please click here

April 2007