Integrated Fish Production

Problem adressed Fish farming is an agricultural activity that can deeply improve already existing farming systems. For example, it can increase the water availability to other cultures or it can increase the farm income when livestock is associated or when cultures are conducted in the pond itself (rice when full, other cultures when drained). On the other side, fish farming can also benefit from agricultural by-products generated by other activities, as they can be used to increase the quantity of plankton, that is the natural food of fish. But in return, the management of such an integrated fish farm is complex and implies to respect some standards. | Problem addressed Objectives Techniques Costs Targeted Livestock System Impact Monitoring: EIA, Indicators References

Objectives

The objective is to obtain a high fish production with numerous positive impacts on the other activities, using as much as possible resources available on the farm. For the fish production, the technical results are a quick growth and a high yield. The economical results are the income and the profit, which are not always lineary linked to the technical results.

Techniques

Several factors will influence the success or failure of an integrated fish farming activity :

- The quality of the ponds. For many people, a fish pond is only a water body, but in fact, it is not. The technology for building ponds has made many progress. The front dyke must be large enough to avoid water and nutrient loss by seepage. The pond bottom declivity must be high enough to allow a complete and rapid draining, in particular at the end of the emptying operation when the fish suffer from the low water quality. In some cases, the pond profile has to be adapted to the culture of complementary productions during fish growth (rice) or draining.

- The fish density (number of fish per surface unit). The fish density must be adapted to the amount of food (natural and artificial) available. With a given feeding level, when the density is too high, the growth stops ; when it is too low, the yield is bad.

- The fish polyculture (culture of several fish species in the same pond). In an integrated fish farm, fish production relies mainly on the natural food, even if an artificial food is used. It is then convenient to use fish species with complementary feeding regimes (herbivory, benthivory, planktivory etc.), in order to exploit all available trophic resources. This is called polyculture. Some interactions between different fish species may even promote a better growth than if each fish was to be produced separately (for example, tilapia provide a better oxygenation of water, which benefits other species). But some other interactions are negative and induce a decrease of the fish production (trophic competition between fish species). The ratio between all the species is then to be clearly identified.

- The pond fertilization. It is possible to increase the quantity of natural food by fertilizing the water. The fertilizer’s or manure’s organic and mineral nutrients are used by bacterias and plants, mostly micro-algae, which are then consumed by filtrating organisms, mostly zooplankton. All these organisms are then eaten by fish, so that the production is greatly improved. Chemical fertilizers are efficient at a low dose, but some can induce toxicity problems. Organic fertilizers are cheap but can induce oxygenation problems, as a consequence of the microbial degradation of the organic matter it contains. Organic fertilizers can be applied by breeding livestock in shed over or near the pond.

- The management of other cultures and livestock. The production of other cultures in association to fish farming relies mainly on each crop’s traditional technologies, but some factors, in particular the variety, may be adapted. The use of some pesticide can also be restricted if it may kill fish or reduce its growth. In the case of an integration aquaculture-livestock, the animal quantity must be defined. For pigs, livestock generally recommended are 30 to 85 pigs.ha-1 and for ducks, 1000 to 3500 ducks.ha-1. The main constraint is related to the fact that the farmers have to master perfectly the two breedings.

Costs

The main cost is the construction of the pond, although many small farmers, with low financial resources but high working capacity during seasons where work on other cultures is reduced, can construct it themselves.

The most important cost during the production is the artificial food, but it isn’t so frequently used on integrated fish farms, as fertilization alone is very efficient and is more widely employed. Manure is cheap and efficient but the quantities needed to obtain a good production are so important that they make its use uneconomical if they are not available in the proximity of the farm and need to be transported. Mineral fertilizers are more expensive but sometimes, their use is economically more profitable.

Targeted Livestock Systems

Farming system with aquatic ecosystem management

Grazing System

LGA | LGS1 | LGS2 | LGS3 | LGH1 | LGH2 | LGH3 | LGT1 | LGT2 | LGT3
N | N | N | N | N | N | N | N | N | N

Mixed System

MCG | MCR | MCC | MFF | MEF
Y | Y | Y | Y | Y

Industrial System

IFP | IPL | IPG | IRM | IDU | ISL | ITN | IMP
N | Y | Y | Y | Y | N | N | N

Impact

- Positive environmental impact

- Improved use of all available farm resources.
- Promotion of locally available manure and agriculture by-products.
- With some endangered fish species (Arapaima gigas for example), diminution of the fishery pressure on wild populations.

- Negative environmental impact

- Water pollution (eutrophication) in case of excessive fertilization or if many farms are in production in the region.
- Low oxygen content of water in case of excess of organic fertilization.

Monitoring: EIA, indicators

> - Water turbidituy and colour: Secchi disk (black and white disk used to determine the turbidity by measuring the deepness at which the disk disappears when introduced in water).
> - Fish behaviour.
> - Intermediary growth and yield determination using sampling.

References

Billard R., 1995. Les carpes: biologie et élevage. INRA,. Paris, France : pp. 387.

Hepher B., Pruginin Y., 1990. Commercial fish farming. John Wiley & sons, New York, USA. pp. 261.

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