1.1 Aquaculture
1.2 Systems and scale
1.3 Rural aquaculture
Aquaculture or farming in water is the aquatic equivalent of agriculture or farming on land. Defined broadly, agriculture includes farming both animals (animal husbandry) and plants (agronomy, horticulture and forestry in part). Similarly, aquaculture covers the farming of both animals (including crustaceans, finfish and molluscs) and plants (including seaweeds and freshwater macrophytes). While agriculture is predominantly based on use of freshwater, aquaculture occurs in both inland (freshwater) and coastal (brackishwater, seawater) areas.
FAO (1988) introduced a definition of aquaculture which reduces its confusion with capture fisheries:
Aquaculture is the farming of aquatic organisms, including fish, molluscs, crustaceans and aquatic plants. Farming implies some form of intervention in the rearing process to enhance production, such as regular stocking, feeding, protection from predators, etc. Farming also implies individual or corporate ownership of the stock being cultivated. For statistical purposes, aquatic organisms which are harvested by an individual or corporate body which has owned them throughout their rearing period contribute to aquaculture, while aquatic organisms which are exploitable by the public as a common property resources, with or without appropriate licences, are the harvest of fisheries.The above definition is significant as it introduces a social criterion (ownership of the stock throughout the rearing period) to qualify the production technology aspects.
In some countries, aquaculture depends on capture fisheries for its supply of wild seed and feed. The production of seed from a hatchery is defined as aquaculture but the subsequent production of adult fish falls within aquaculture only if the stock is owned by an individual or corporate body during grow-out. If hatchery-produced seed are stocked in a large water body, and the production harvested by the public, it is categorised as culture-based or enhanced fisheries.
Ownership of fish-aggregating devices such as brush parks in large water bodies does not confer ownership of the capture fisheries and is not aquaculture.
Although the FAO definition of aquaculture is an important contribution to our understanding of aquaculture, grey areas remain especially in relation to ricefields and culture-based fisheries. FAO classifies rice-cum-fish culture as aquaculture but there are complex inter-relationships between wild fish and aquaculture in ricefields which defy generalisation and definition. Farmers have caught wild fish in ricefields since time immemorial, often building trap ponds to harvest them when water levels fall at the end of the rainy season. The fish benefit from the modified rice field which, besides providing them with a habitat, also facilitates harvest. Farmers may also make the rice field dikes and screen outlets higher to facilitate growth and harvest of wild fish without resorting to either feeding or intentionally stocking wild or hatchery-raised seed.
Stocking of water bodies with either wild or hatchery-raised seed is aquaculture if the stock is owned individually or by a corporate body until harvest but it becomes capture fisheries if there is open access for the general public. Complex social issues relating to use of traditionally communal water bodies for aquaculture lead to difficulties, often at the expense of the rural poor.
The type and scale of intensity of aquaculture systems are best considered in relation to the evolution of agriculture since agricultural and aquaculture systems follow similar paths and are often integrated. Indeed, most small-scale aquaculture may need to be integrated with agriculture, as future fish farmers already farm crops and livestock and nutrient inputs for aquaculture are most likely to originate on-farm in inland areas (Edwards et al., 1988).
Settled agriculture was classified into three phases to illustrate the way aquaculture may evolve on small-scale farms (Ibid.), recognising that there are examples of Phase 2 which are skipped in the process of modernisation:
1. Settled Agriculture Phase 1 (crop-dominated) is characteristic of pre-industrial societies with most land under food crops. Livestock are kept mainly for draught; the system includes scavenging poultry and pigs. There is limited integration between crops and animals. Large ruminants that depend on rough grazing stubble in the fields after crop harvest and are fed straw. Rice bran is fed to pigs and poultry. Livestock manure fertilises the field but the farming system is mainly crop-based due to the limited number of livestock. This system was characteristic of much of Western Europe until about 1850 and applies to many small-scale farms in developing countries today, particularly those in marginal areas. In areas of lighter population density where fish is a traditional part of the diet, farmers rely mostly on capture fisheries. As population densities increase and capture fisheries decline, there may be recourse to aquaculture. Most small-scale farmers in Asian developing countries as well as in Africa and Latin America fall within this category as they have little or no involvement in aquaculture.
2. Settled Agriculture Phase 2 (integrated crop/livestock) was characteristic of much of Western Europe and the eastern USA from 1850 to 1945. These were called mixed farms because livestock production was based on arable crops and improved pasture. Livestock were closely integrated with crops because the former fed on the latter, and manure helped maintain soil fertility together with nitrogen fixing legumes. They were almost a closed self-sustaining system relying on local or farm-based nutrient cycling (Tivy, 1987). Their aquaculture equivalent is the traditional Chinese integrated agriculture-aquaculture system.
3. Settled Agriculture Phase 3 (industrial monoculture) is based on agro-industrial inputs. Initially developed in 1850, it only began to replace the traditional mixed farming system in Western Europe in 1950. Its major features are improved genetic varieties, chemical fertilisers, herbicides, pesticides, pharmaceutical chemicals, feed concentrates, pelleted feed and mechanisation. Most phase 3 farms raise only a single species because of increasing technical complexities and economies of scale. Much western and Japanese aquaculture belong to phase 3, as is recently developed intensive shrimp culture.
This classification may be compared to that of the World Commission on Environment and Development (WCED 1987) which was elaborated further by Chambers et al. (1989), and utilised by Demaine (1994) for his analysis of the agenda for sustainable agricultural development in the Asia-Pacific region.
Global agriculture is divided into three classes: resource-poor agriculture; Green Revolution; and industrial agriculture. The third type of agriculture is associated with rainfed dryland, upland and swampy lowland, often peripheral areas where farming systems are much more fragile and as a consequence, complex and diverse. Abbreviated as “Third CDR” (complex, diverse, risk-prone), it broadly corresponds with Settled Agriculture Phase 1.
Green Revolution agriculture is usually found in national “agricultural heartlands” in fertile areas, either irrigated or rainfed lowlands, close to major population centres. Although it includes both large and small farms it essentially corresponds to Settled Agriculture Phase 3 as does the WCED industrial agriculture; both are monoculture which rely heavily on agro-industry. The latter comprises large farms and is mainly found in the developed world although there are enclaves in developing countries.
Table 1. General correlation between various schema for the classification of scale of farming systems.
|
System |
Authors |
||||||
|
Settled Agriculture Phase 1 (crop dominated) |
Settled Agriculture Phase 2 (integrated
crop/livestock)* |
Settled Agriculture |
Edwards et al., (1988) |
||||
|
Resource-poor agriculture |
|
Green revolution agriculture |
Industrial agriculture |
WCED (1987) |
|||
|
Subsistence* |
Artisanal* |
|
|
Lazard et al., (1991) |
|||
|
|
Specialised* |
Industrial* |
|
||||
|
Type 1 aquaculture* |
|
|
Martinez-Espinosa (1995) |
||||
|
|
|
Type 2 aquaculture* |
|
|
|||
|
|
Balanced model* |
|
Edwards et al., (1996) |
||||
An important difference between the types of agriculture defined by Edwards et al. (1988) and WCED (1987) is the inclusion of an integrated crop/livestock category by the former in Settled Agriculture Phase 2. This has been proposed as an important pathway by which resource-poor small-scale farming households may become aquaculturists (Edwards, 1993). However, a balanced model that uses both on-farm and off-farm resources may be required for aquaculture to contribute significantly to increased welfare (Edwards, et al., 1996). Other schemes for defining scale or intensity of aquaculture systems may be related to the classification discussed above (Table 1).
In a study of Francophone Sub-Saharan Africa, Lazard et al. (1991) characterised four types of aquaculture by degree of commercialisation:
More recently, Martinez-Espinosa (1995) proposed two types for the development of rural aquaculture:
These categories may be compared with the more common classification of aquaculture based on productive technology, particularly feed, dividing culture systems into extensive, semi-intensive and intensive. These terms are widely use but defined in various ways, often imprecisely, or not at all. The usage outlined below is in common use (Edwards et al., 1988; 1993):
Although the classification is based on feed, increasing intensification is correlated with higher levels of other inputs such as seed, labour, capital and management. The system is less relevant for molluscs than for crustaceans and finfish because molluscs are always cultured on natural food irrespective of the level of other inputs. It has limited relevance for cultivation of aquatic plants.
The term rural aquaculture derives from the traditional dichotomy of development: rural or agricultural and urban or industrial. The overriding priority in rural development is to address widespread poverty and inequity in developing countries (WCED, 1987). Implicit in the term is the promotion of aquaculture systems appropriate to the resource base of small-scale farming households either through extensive or semi-intensive aquaculture (Martinez-Espinosa, 1995). Given that the term implies an orientation towards the needs of the lower socio-economic groups, rural aquaculture may cover both inland and coastal aquaculture systems.
There is also a need to consider intensified production but in an environmentally sustainable way. Once farmers gain confidence and experience at lower levels of production, they may wish to change their level of production from subsistence or artisanal to entrepreneurial or commercial and become increasingly specialist aquaculture farmers. This requires increasing use of off-farm, agro-industrial inputs and greater involvement with urban markets. But it needs to be done in a balanced way, combining Settled Agriculture Phases 2 (integration) and 3 (agro-industrial inputs) to avoid environmental degradation (Edwards et al., 1996).
Rural aquaculture is broadly defined as follows:
... the farming of aquatic organisms by small-scale farming households or communities, usually by extensive or semi-intensive low-cost production technology appropriate to their resource base. The resource-poor base of most farms requires off-farm agro-industrial inputs to intensify production. This implies use of mainly inorganic fertilisers rather than formulated feed to provide low market value produce affordable to poor consumers.An abbreviated version of the definition is as follows:
... the farming of aquatic organisms by small-scale farming households using mainly extensive and semi-intensive husbandry for household consumption and/or income.
