Markets[edit | edit source]
Local markets[edit | edit source]
Tilapia's reputation in tropical countries does not need any major promotion; the fish is well distributed and commonly accepted as a preferred fresh water fish. However, prices are very variable according to the country (see below: Actual price estimates). It is, however, strongly recommended to complete, first of all, a market study that will demonstrate:
- The importance of tilapia on the local market
- The main commercial products (whole fish, fillets, fresh, frozen, etc.)
- Realistic volumes of production that can be envisaged by the project (without causing market disruption)
- General market prices for competitive products (from aquaculture and fisheries activities).
- Competition in the market from other producers or farmers and, especially, imports
Export markets[edit | edit source]
In order to have successful access to European or American markets, 2 major points have to be considered:
The first is related to product quality and quality control procedures that we can not tackle in this publication. Regulations and recommendations for fish processing factories must be respected in order to match European and American standards otherwise there is no point in hoping for the export opportunity.
The second aspect concern production levels. For fresh products (airfreight and all related constraints), relatively small quantities can be considered; for example 500 kg to 1 tonne per week. Regularity of supply is not only very important for negotiations with airfreight companies, but also for negotiations with the client whose prime interest is surety of supply at known prices. For frozen products, shipments are usually around 20 tonnes (a complete container). Knowing that western markets are favouring fish fillets, and that the filleting yield of tilapia is around 32% (skin-off fillets), it appears that commercial projects have to look at substantial production levels.
Markets in neighbouring countries or countries of the same continent have also to be studied since they can provide interesting spot and long-term opportunities (usually for frozen products).
Current price estimates[edit | edit source]
On local markets, as was indicated previously, the sales values of tilapia can vary considerably dependent on the country.
Export markets concern tilapia fillets mainly. While this product is already well introduced on the US market, it has only recently been available on European markets. Tilapia fillet is marketed as a fresh or frozen product, the fresh fillet having a higher sales value. Regular prices for tilapia fillets on the European market remain to be established due to the variability in supply and the lack of consumer knowledge concerning the product.
For the US market, the CIF price for fresh fillet is about 7 US$/Kg and about 6 US$/Kg for the frozen product.
Eventually, one could predict that prices in Europe will follow the US prices; the first imports in Europe seem to be based on 6,54 US$/Kg, CIF price for the retail market. In Europe, in order to estimate the tilapia fillet price, one can base valuations on two product indicators. Firstly, the fresh cod fillet price (reference fish) which fluctuates between 6,00 and 8,3 US$/Kg. Secondly, the Nile Perch7 fillet price which is worth about 6,00 US$/Kg for fresh fillet and 5,00 US$/Kg for frozen fillet.
Nile Perch is fished from Lake Victoria and other Regional Lakes; exporting countries are mainly Kenya, Uganda and Tanzania
Legislative and legal aspects[edit | edit source]
Before the implementation of a fish farm, it is absolutely necessary to obtain all of the permits concerned by the construction and operation of the activity. Operating permits, water regulation rights (input and output-drainage), construction permits etc.
This aspect is particularly important because, in many countries, several months (sometimes, even years) are necessary to obtain all of the permits required.
Some countries do not allow the import of 'exotic'8 species. Even in the case of tilapia, the problem must be considered because the local tilapia species are not necessarily adequate for fish farming while a non-native tilapia species may provide a better economic performer.
'Exotic species' usually refers to non-native species
A stronger and important recommendation is to envisage the achievement of an environmental impact study (EIA), a study which shows that the promoter is conscious of environmental matters and has taken this particular aspect into consideration. Obviously, demonstration that there is no negative impact on water resources or other local environmental matters is a desirable position.
Mooring systems[edit | edit source]
Good care must be paid for the mooring (anchoring) system. This will be selected following the speed of the current, winds and any effect that could move the cage and require a special study. Note that mooring systems for square cages are cheaper than those for round cages.
Problems for aquaculture projects[edit | edit source]
Pollution[edit | edit source]
During the investigations for the suitability of an aquaculture project, it is important to identify any potential sources of pollution; these may be of organic, chemical or physical origin. Sites exposed to any major pollution risk must be rejected.
It is also important to evaluate auto-pollution risks for the project. The fish farm must be adapted to the environment within which it is to be implemented in order that the project itself not be considered as a source of pollution.
Diseases[edit | edit source]
Diseases often occur when rearing conditions deteriorate (poor tank/cage maintenance, pollution incidence, too high stocking densities, etc.). A good maintenance programme will reduce considerably the risks and incidence of disease. The tilapia species used for fish farming are generally very robust fish but poor sanitary conditions will inevitably lead to a decrease in productivity with the possibility of mortalities.
Numerous types of fish diseases can occur which can be of bacterial, parasitic or viral origin. It is advisable in all cases to obtain expert advice and take rapid action.
Holding a large variety of different species within the same fish farm will also increase the risks significantly.
The introduction offish from other fish farms to the project must be severely controlled before entry and mixing with the fish population on the farm (e.g. quarantine, disinfecting the new stock...).
Fattening/On-growing[edit | edit source]
Fattening or on-growing represents the final rearing stage before harvest and sale. It concerns the stage of fish growth between ± 40 g. to the harvest-size fish of 200 to 800 g., the individual size being determined by market demand. Generally, one can consider that urban markets are looking for fish that exceed 400-450 g. as a minimum market size and many developed(2) markets require >600 g.. These factors vary considerably between different market sectors and countries and, obviously, influence farm production planning and therefore its operational economics.
(2) 'Developed' refers particularly to European and North American Markets as well as supermarkets. Globally, the average growth of O. niloticus is between 1 and 2 g. per day (depending on individual size and growing conditions). This estimate constitutes a prudent average, referring to data for an intensive growing system for a mixed sex population reared at a suitable temperature (> 25 °C).
Better growth performance is achieved when 100 % male populations are used as the stock and also when improved genetic strains are reared. Some fish farmers can obtain growth of 4 g. per day, for fish >350 g. individual size under such circumstances.
It is therefore possible to forecast the necessary time required for the production of fish for the market, while integrating all of the rearing parameters that need to be assessed individually and the following graph represents the theoretical growth rate for Nile Tilapia in intensive farming conditions.
- Theoretical growth of sex-reversed O. Niloticus reared in intensive conditions
Nutritional aspects[edit | edit source]
The tilapia species that are commonly used in aquaculture (O. aureus, O. niloticus, O. mossambicus, etc.) are microphage species and, consequently, have a small stomach and a narrow oesophagus. Feeding methods must then be adapted to these physiological characteristics which necessitate frequent feedings during the day.
Feeding trials have shown that both the food conversion ratios3 and the growth rates are improved if 4 feed rations are distributed during the day. The use of more than 4 feed rations has not shown any real improvement under experimental conditions (except in the case of fry). Nonetheless, it is likely that increased feeding periods (>4 per day) that are combined with well-determined ration size, which would be variable following the individual size of the fish, could improve production significantly under commercial conditions.
3 F.C.R.
As mentioned previously, tilapia fry are more demanding in their diet than the adults, notably in respect of dietary protein requirements. A formulated (milled) meal, containing a 45 % protein level, satisfies the energy requirements of tilapia fry. It is important to note that the protein content must be partially of animal protein origin and that the use of vegetable materials as the unique source of dietary protein is not adequate.
Appropriate animal protein sources include abattoir by-products (e.g. blood, bone and meat meals) and fishmeals and oils can be integrated as well. Vegetable-based complements such as soya meal, maize meal, cottonseed cake etc. can also be used. Where possible, the incorporation of a vitamin complex is recommended in order to account for specific dietary requirements.
Feeding rates also depend on different parameters such as:
· Age and size of the fish. · Feed composition and its energetic value. · Temperature and oxygen levels of the water. · Water turbidity. · Rearing system used (intensive, semi-intensive, etc.)
Feeding rates are usually calculated as a percentage of the biomass concerned in the individual rearing units, relating to the average body weight of the fish population but can be adapted relative to the other rearing parameters.
The goal of all feeding strategies is to get the maximum amount of feed into the fish without losses; consequently the feed type, composition and manner of distribution is of key importance to the success of any commercial fish farm.
The use of automatic feeders can assist avoiding use of these approximate calculations (different parameters4 can be difficult to appreciate and to integrate but influence the fish appetite; in many cases such considerations are the decision of the fish farmer and based on personal experience).
time of day, water turbidity, abrupt temperature change etc.[edit | edit source]
The demand feeder is a very simple mechanical unit composed of a pellet feed reservoir equipped with a pendulum system, which drops pellets into the water when the fish hits the shank of the pendulum. The fish feeds as desired, ad libitum. This significantly reduces feed wastage and encourages a feeding rate between optimal and maximal. This system is also labour saving because the reservoir need only be filled once per day compared to manual feeding of each unit 4 times per day.
Pressed or extruded pellets are the usual forms of presentation of commercial feeds. Extruded feeds, usually termed 'high-digestibility' due to the manufacturing process, are often considered to be the best option. These feeds can also be fully or partially floating pellets, which allows a higher stability of the pellet in the water rather than dissolving and being lost to the fish.
Pellet size is also important and must be adapted to individual fish size, in order to ease physical ingestion (due to the small oesophagus). Pellets that are too large can only be 'nibbled' and cause significant waste.
Feed quality is not only related to the formula of composition but also to the physical particle size of the raw materials employed. Small particle size will facilitate digestion of the food while poorly milled materials (particularly of hard components such as corn) can create health problems.
Important Factors and References
Feeds usually constitute the most important operating cost for any farm and efficient growth and food conversion are the main keys for profitability. It is therefore important to understand the key analytical tools that are used by all farmers in order to analyse and understand how a fish farm is performing.
Food conversion ratio (FCR):
This phrase expresses the amount of feed used for the production of fish biomass and is a numeric value; for example, a FCR of 1,8 means that 1,8 kg of food has been used to produce 1 kg of live fish.
Logically, a precise scientific conversion ratio should also take the water content in account, which is around ± 10 % in fish feed and ± 70 % in fish (according to species) but in commercial fish farming, the scientific conversion ratio is rarely if ever used.
Note: In commercial fish farming, the economical food conversion ratio is the more important.
It accounts for all of the conditions encountered including losses (due to mortality, predation, escapees, etc.) in order to give the real economical result of the farm. It is obviously interesting to know how fish perform in 'experimental' conditions that indicate, for example, the performance of a specific batch of fish in a specific tank.
However, it is essential to know how the whole of the fish stock of the farm is going to perform in commercial facilities, including all risks and constraints.
Growth rates:
In fish fanning, the growth rate is expressed in individual weight gain per day (e.g. 1.2 g./day). It can also be expressed as a % of the body weight gain of the fish per day (e.g. 1.5% for a fish of 25 g.).
Globally, the average growth for tilapia species, between fry up to 200 g., is considered to be ± 1 g./day for a mixed sex population. Obviously, small fish grow at a rate of some milligrams per day while bigger fish grow at more than 1 g. per day; the growth curve at early stages can be exponential but this stabilises at later stages.
Optimal feeding rate:
This is the feeding rate, expressed as percentage of body weight, which allows the lowest (therefore, the best) food conversion ratio. The fish receives the amount of food necessary for the maintenance of normal vital functions (swimming, respiration etc.) as well as encouraging growth.
Maximal feeding rate:
This is the feeding rate that allows the highest growth speed. The FCR is usually not as good as that obtained with the optimal feeding rate since the fish are induced to consume more food than is necessary, which leads to waste.
Maintenance feeding rate:
The 'maintenance' feeding rate is used to keep the fish at the same body weight where only the food necessary for sustenance is given. This is generally applied to adult fish and is not recommended for young fish. Tilapia, in case of environmental problems such as oxygen depletion or an abrupt drop in temperature, spontaneously adopts the maintenance rate. Managed administration of this rate is applied when fish have been manipulated (e.g. grading or treatment for disease). Generally, the normal feeding of fish that are stressed results in very poor food conversion.
Fish farming sites[edit | edit source]
The requirements of a fish farm have particular constraints, which limit the possibilities and choice considerably. Water is, of course, the main consideration, where quality and quantity are the prime factors.
In addition, sites must present geological qualities (soil, topography, etc.). geographic qualities (demography, roads network, electricity network, etc.) and economic qualities (production costs, access to markets, etc.).
The evaluation of all of these parameters will guide the investor to the final selection for realising the project. In the tropical regions, a lot of sites have excellent technical characteristics, but are not suitable for the development of a commercial farm due to difficult access, lack of raw material suppliers, lack of personnel and essential support services, distance to markets etc..
Indeed, total assessment of the advantages and constraints has to be done in order to avoid costly mistakes.
Sites with a river boundary[edit | edit source]
The following characteristics need to be considered:
Topography:
It is particularly interesting to identify sites where the natural topography allows water supply and drainage to be done by gravity. This situation presents the major advantage of being much cheaper to operate and is also more secure (i.e. no power cuts). However, the site must be safe from floods and drought.
In some cases, pumping will be considered if cost-effective energy is available (public electricity or generator); in these cases, extensive or semi-intensive fish farming will probably be envisaged.
Altitude is also very important in the tropics; at heights over 1.000 meters; it is unusual to find tilapia farms due to low seasonal temperatures. At these altitudes, carp, bass and other temperate water fish can be reared and, over 1.500 m., trout farming may become possible.
Surface area:
Sites with only a small surface area have obviously more constraints because they imply that intensive (high density) fish farming has to be considered otherwise production potential is severely limited. It is possible to envisage a commercial fish farm on a small surface area for as long as good water supplies are available; for example, Piscimeuse S.A. (Sited at Tihange in Belgium) achieves a production of 450 tonnes per year on 2 hectares of land by using hyper-intensive growing methods. To be able to consider such an intensive fish fanning system, it is necessary to be assured of adequate water and constant energy supply, two factors that are inherent to the intensive farming concept.
In extensive fish farming, usually the productivity is around 6 to 8 tonnes per hectare per annum, consequently the surface required for profitable economics is usually large (>10 hectares)
In a semi-intensive system, involving complementary feeding and sometimes aeration, annual productivity of 40-60 tonne/hectare can be achieved.
In an intensive system, with feeding and aeration, production is estimated rather in g./m3. day (e.g. 150 to 250 g./m3.day), this measurement being a function of the volume of the installations (Tank, cage) rather than the land or water surface which is the alternative benchmark.
Soils
Clay soils are particularly suitable for pond building due to their impermeability. The ideal composition for a 'pond' soil is clay that mixed with some sand (sand acting as a binding agent). Clay alone cracks when drying in the sun while sandy soils are permeable; the mixing of these two elements offers the best material. Soils that are rich in organic material must be avoided due to their permeability and unstable physical nature.
If intensive farming is foreseen in concrete structures, the soil nature is less important, although the ground upon which they are built must be stable and compacted prior to construction. An easy test to appreciate the soil's impermeability is to dig a hole (>1m deep), to fill it with water and to observe if the water seeps away and how quickly. The test must be repeated in different places around the potential site. Taking a handful of soil and moistening it will also allow evaluating its behaviour in contact with water.
In certain cases, it is prudent to proceed to a detailed chemical analysis of the soil, particularly if the presence of potentially noxious chemical substances is suspected (metals, hydrocarbon, etc.).
Water:
Chemical analysis
The preliminary precaution is to obtain a chemical analysis of the water source at the site. The simplest test is to check whether fish and even the target species are present in the river or in adjacent water bodies.
If the specimens captured are systematically small and/or rare, this could indicate an environmental deficiency that is important to identify.
When the aquatic environment is naturally poor (oligotrophic), this is not necessarily a negative consideration, especially if artificial feeding is envisaged. In the case of extensive fish farming, supplementary fertilisation of ponds has to be foreseen.
All potential sources of pollution of the water source of a site must be identified and assessed for impact; this can be domestic or industrial pollution, including other fish farms or agricultural activity upstream.
Physical analysis
Water Temperature
Water temperature is a very important criterion for the assessment of potential fish farming sites. Weekly/monthly temperature data must be available in order to allow the formulation of projections for the growth potential of the fish as well as for the planning of breeding programmes.
For the farming of tilapia, a permanent water temperature of 27°C would be described as an ideal situation. These conditions are rare in real situations. However, the temperature must not drop below 18°C (except for a very short period) and must not exceed 34°C (dependent on stocking densities).
Lethal extremes of temperature for tilapia (dependent on species and stocking densities) are around 12°C and 42°C.
The objective therefore is to identify a site where the water temperatures range between 24 and 30°C for most of the year (i.e. >10 months per year).
Water turbidity
Turbidity (cloudiness) has an effect on fish appetite, feeding and, therefore, on growth. Turbidity due to plankton production is, on the contrary, rather beneficial to tilapia and especially for the microphagous species (O. niloticus, O. aureus), providing a complementary diet in this natural food.
For juvenile production, 'green water' is appreciated because it constitutes a natural food that will benefit the fry, principally by avoiding deficiency in some essential nutriments. Fry and fingerlings produced in these conditions are often more robust. When the water is very rich in phytoplankton, it is important to check regularly and often the levels of dissolved oxygen in the water, particularly during the night. One must also note that not all algae are 'good' and some species are even toxic upon consumption by fish.
Water turbidity due to the presence of mineral materials (sediments and silt) are always unfavourable for tilapia resulting in poor growth, disease and other pathological symptoms leading to fish losses.
This does not mean that tilapia cannot tolerate turbid water, but that sites which present this condition regularly or permanently must be avoided. This condition is not so important for catfish species (e.g. Clarias sp.) which survive well in turbid environments.
Quantitative aspects of water supply
The lowest levels of water availability, and their frequency, will determine the quantitative possibilities of the production as well as influencing the type of production system that should be used (extensive, semi-intensive, etc.).
Minimal and maximal water flows have to be known, evaluating the possibilities of drought and flood risks. Once these have been established, the consideration of 'water flow/surface area available' will determine the type of farming to be applied, integrating the aspects of the other production parameters (temperature, oxygen...).
It is very difficult to establish a universal equation that allows a consistently reliable means of choice; it is more of a case-by-case study that is needed. Globally, one can estimate that 5 m3 of water per hour are required for the production of 1 tonne of fish per year in an intensive farming system.
In an extensive system (or semi-intensive), 1 m3/hr. is necessary to produce one tonne offish per year, remembering that this is only a rough estimation.
Sites bordering a lake[edit | edit source]
Tilapia farming can also be done within floating cages, more often on lakes, but also on rivers. Even if cage farming is envisaged, a site on land is also needed for the production of fry and fingerlings. It is possible to breed tilapia in cages or 'hapas' (small mesh cages), but fry production is usually better in earthen ponds where the development of natural feed is encouraged. Moreover, for physiological and behaviour purposes, tilapia species breed better in conditions where a natural floor substrate is available (sand, clay, etc.) due to the nesting procedures of reproduction.
Note: As mentioned previously, cage farming can also be done on river sites. However, selection must be made with care in order to avoid site cages in strong currents which tilapia do not like and to be protected from flood conditions.
Characteristics of suitable sites:
Surface area:
To operate in optimal conditions, large water bodies must be selected; they offer more security from the points of view of water quality & quantity. The bigger the lake, the better is its capacity to absorb the environmental effects of the fish farming activity. In addition, the thermal inertia (less temperature fluctuation) of a large water body is an interesting factor. For a fish farm of commercial scale, it is recommended to investigate lakes that exceed 10 km2.
Depth:
Preference is usually given to the sites that are deepest since this factor decreases the negative effects of sedimentation of fish waste and uneaten feed that can accumulate underneath the cages. A bottom depth of more than 5 meters from the bottom of the cage is recommended. A depth of 20/25 meters is ideal since this allows a good dispersion of waste but does not present major difficulties for the installation of the anchoring system that is needed by floating cages.
Water Currents:
Ideally, one wants to provide shelter from storms by choosing a protected area while allowing a constant water flow through the cages to assure a good water exchange rate. This provides more constant water quality and good oxygen levels within the cages.
Water exchange in the Water body
This is an important parameter, particularly on small reservoirs where a good water exchange rate can compensate for a smaller surface area.
Temperatures:
As for the river conditions described, the temperature cycles of the lake must be known throughout the year. In remembering that the thermal inertia of big lakes is an important factor, the temperature fluctuations are reduced and the amplitude of variation reduced.
Note: Other aspects like site security (including theft), proximity of the processing factory, etc require study for site selection approval.
Sites on Water Springs or Bore-holes[edit | edit source]
Globally, sites that have access to a water spring, a natural resurgence or a well/bore-hole in the water table offer the advantage of using pollution-free water, at more constant water temperatures.
Care must be taken that in respect of water tables that are close to the land surface since these can be polluted through agricultural activities. Additionally, borehole water must be checked for the presence of heavy metals and, notably, for iron-containing salts. These can precipitate, once oxygenated, causing material and pathological problems.
On the other hand, de-gassing of this type of water is often necessary in order to eliminate the presence of super-saturated gases (e.g. nitrogen) and to oxygenate the water. For the other conditions, the considerations for these sites are the same as river sites.
Conclusions[edit | edit source]
The selection of a suitable site for aquaculture must take all of the parameters for safe and sure operation into account. Up to this point, only the technical aspects have been presented. In many tropical countries, many sites can be deemed as being suitable technically because they offer, for example, good water flows, good temperatures and land availability.
The limiting factors are more often the availability of fish feeds, local support services (electricity, telephone, qualified technical staff...), the distance to the market and other logistical considerations. Intensive fish farming can only be envisaged if formulated feeds of high quality are available or, at least, the raw materials required for the manufacture of such feeds.
Source: Food and Agricultural Organisation (FAO) of the United Nations[edit | edit source]
In terms of volume, tilapia is already the fifth most important fish produced in the world. There is no doubt, that, in the near future, this fish will have an important position on the market place in Europe, due to its physical and gustatory characteristics (white flesh, no bones, and light taste).
At the present, Asia is responsible for some 80% of the world's aquaculture production, while Africa produces 1% and Latin America 2% despite both regions having very good aquaculture potential.
Demand for fish and fish products is increasing by about 2 to 2,5 % per year and fisheries resources are considered to be at their maximum potential now and cannot be increased without compromising the equilibrium in the oceans.
The challenge for aquaculture is to double production during the next 15 years. Within such a context, aquaculture should have a good outlook for the future and particularly for species that are less demanding in protein, such as tilapia.
However, commercial aquaculture is a highly specialised field that requires a particular expertise. This activity, as for all agricultural projects, is also very demanding and requires a high level of motivation at all level if success is to be achieved.
See also[edit | edit source]
External links[edit | edit source]
http://web.archive.org/web/20180504063723/http://www.adf.gov:80/enews0804sal.htm Netting higher earnings for tilapia farmers on lake volta
Fish farming facilities[edit | edit source]
The following are the utilities that are used in fish farming.
Fry production[edit | edit source]
Earthen ponds:
Earthen ponds are the most commonly used system for tilapia fry production. Ponds of 200 to 300 m2 are preferred; this size eases the collection of fry while being, at the same time, highly productive. The average depth should be around 1 metre. If concrete walls are envisaged (to reduce the effects of long term erosion), it is important to remember that square ponds are better than long narrow ponds, due to the relation between surface area and perimeter. It is prudent to foresee the use of an aeration system, if possible, so the wiring for electricity distribution should be foreseen at the time of construction.
Breeding arenas:
Arena tanks are usually circular concrete tanks, the edges of which are very shallow and which allow, when the water level is dropped slightly, to harvest the fry that prefer the shallow, warmer areas, along the edges. The diameter of these tanks varies, but rarely exceeds 5 meters.
In this type of facilities, fry are collected daily using a small mesh, scoop net after dropping the water level by a few centimetres. They can be induced into the channel by feeding.
Hapas:
Hapas are small cages made of fine mesh (e.g. mosquito netting), generally suspended on stakes that are fixed in the bottom of the pond. Hapas are usually installed in shallow areas either in ponds or in protected areas alongside a lake. Brood fish are stocked in the hapas and fry are collected regularly, applying an appropriate harvesting technique (very common in Asia).
Note: If catfish (Clarias) farming is envisaged, a special hatchery has to be built. The main equipment is a water re-circulation system equipped with "zoug" bottles for the incubation and hatching of eggs. In the tropics, the catfish-breeding season starts at the beginning of the rainy season. Natural (or synthetic) hormones are used to both induce and synchronise the spawning. Breeding this fish requires technical knowledge and practise (See: Bibliography).
