Fuente: http://www.fao.org/docrep/field/003/ab467e/AB467E04.htm
3. FEEDING METHODS - FERTILIZATION AND
SUPPLEMENTARY DIET FEEDING
3.1 Introduction
At present over 90 percent of finfish and shrimp aquaculture production within third world
and developing countries (including Latin America and the Caribbean) is realized within
semi-intensive or extensive pond production systems employing a fertilization and/or
supplementary diet feeding strategy. Here, in contrast to complete diet feeding, the dietary
nutrient requirements of the farmed species are met either entirely or partly (in conjunction
with an exogenous supplementary diet) through the production and consumption of natural
live food organisms within the water body in which the fish or shrimp are cultured.
3.2 Pond Fertilization
3.2.1 The pond ecosystem and primary nutrient cycles
Since the aim of a fertilization feeding strategy is to augment the production of natural food
organisms within a water body, it is perhaps useful to first describe the basic aquatic food
chain or ecosystem and the underlying primary nutrient cycles operating within a pond
ecosystem. Figures 8 and 9 show a generalized model of a simple aquatic ecosystem and
an example of a natural pond food web ending in common carp (C. carpio), respectively.
All aquatic ecosystems, including a fertilized fish or shrimp pond, rely on the simultaneous
operation of two interlinked food chains; a light dependent “autotrophic” and grazing food
chain, and a non-light dependent “heterotrophic” or detritus food chain. As the name
suggests, the autotrophic or organic matter synthesizing food chain relies on the fixation of
solar energy by green plants during photosynthesis with the production of new organic
matter from carbon dioxide and water, and the subsequent consumption of these plant
organisms by grazing animals. Although green plants, and in particular phytoplankton are
the principal autotrophs or “primary producers” operating within a pond ecosystem, certain
non-photosynthetic anaerobic bacteria and blue-green algae are autotrophic in that they
are able to synthesize organic matter (ie. new cell biomass) from inorganic carbon by
using chemical energy derived from the cellular oxidation of inorganic substrates such as
hydrogen sulphide, sulphur, nitrogen, divalent iron and hydrogen (collectively these are
termed chemosynthetic autotrophs as opposed to the photosynthetic autotrophs). By
contrast, the heterotrophic or organic matter consuming food chain relies on the
microbiological degradation of non-living organic matter or detritus into new microbial
biomass with the release of inorganic nutrients and carbon dioxide; the new microbial
biomass (mainly bacteria) serving as a feed source for protozoa, nematodes and other
benthic animals, and the released inorganic nutrients and carbon dioxide in turn being
available for further photosynthetic production by the primary producers or autotrophs.
All pond food organisms, including autotrophs and heterotrophs, consist mainly of carbonC, nitrogen-N and phosphorus-P (ie. composition of phytoplankton grown on a nutrient rich
medium being about 45–50%C, 8–10%N and 1%P on a dry basis: Edwards, 1982), and
consequently are dependent on the biological supply of these primary nutrients for their
growth. The basic chemical and biological pathways involved in the supply and cycling of
C, N and P within a natural pond ecosystem are shown in Figure 10, 11 and 12,
respectively. From an understanding of these nutrient cycles it can be seen that the natural
productivity of an enclosed water body can be increased with careful management,
through the controlled addition of chemical inorganic fertilizers (by feeding the autotrophic
food chain) and/or organic manures (by feeding the heterotrophic food chain).
Figure 8. Generalised representation of a simple aquatic ecosystem. The lightly shaded
blocks represent the biomass of each type of organism. The stippled arrows show the
direction and magnitude of energy flow while the single line arrows indicate the
transference of nutrients either through direct consumption, excretion or death, and
bacterial decay. Energy is the amount of solar energy taken up by the primary producers
(green algae and higher plants). Ecosystems are usually divided into a grazing food chain
of large animals and a detritus or decomposer food chain of microorganisms (Source:
Eltingham, 1971).
Figure 9. Schematic representation of a pond food web ending in common carp (Cyprinus
carpio; Hepher and Pruginin, 1981)
3.2.2 Preparation of the pond bottom prior to fertilization
The soil of the pond bottom, and in particular the mud layer 1, is considered to be the
“chemical laboratory” and “primary nutrient store” of the pond ecosystem, and as such
plays a vital role in the maintenance of pond productivity (Figure 10–12: Mortimer, 1954;
Huet, 1975; Vincke, 1985; White, 1986). However, the success of a pond fertilization
feeding strategy, in many instances, depends upon the initial drying and/or chemical
treatment of the pond bottom with lime.
3.2.2.1 Pond drying
The advantages of air drying and exposing the pond bottom to atmospheric oxygen and
sunlight prior to fertilizer application have been summarised by Mortimer (1954), Vincke
(1985), Clifford (1985), Fast (1986), Stokes and Smith (1987) and Wilson (1987), and
include:






1
Improvement in soil texture and primary nutrient availability for future phytoplankton
production by facilitating the breakdown and decomposition of organic matter
through oxidation with consequent mineralization of the surface mud layer.
Reduced mud sediment demand for oxygen once the pond is filled with water.
A well aerated and partially oxidised soil, makes the bottom better suited for
colonization by desired benthic food organisms.
Oxidation and removal of undesirable metabolites, such as hydrogen sulphide (a
by-product of anaerobic respiration of sulphur bacteria), which if allowed to
accumulate may inhibit the growth of phytoplankton and the cultured fish or shrimp.
Elimination of fish or shrimp predators, parasites and their eggs, and unwanted
aquatic macrophytes.
Facilitates the cropping of the cultured fish or shrimp and the removal of excessive
mud or silt deposits from the pond bottom, the latter being a valuable fertilizer for
agricultural crops.
The pond mud or sediment generally consists of a mixture of settled organic matter or detritus (dead plant/animal
fragments and faecal matter; fresh or in a state of bacterial/microbial colonization and decomposition), live benthic organisms
(algae, protozoa, nematodes oligochaetes, polychaetes, gastropods and insect larvae), and inorganic minerals. The latter
may be present as coarse sand or silt particles, precipitated mineral salts, bound cations adsorbed onto negatively charged
colloidal clay/humus particles, or as free dissociated cations within the interstitial water of the pond mud (Boyd, 1982; Coche,
1985).
Figure 10. The carbon cycle
Equilibrium depends on pH; the solubility of CO2 increasing with pH. In addition to the
inorganic C forms shown, precipitation of calcium carbonate may occur from the
1
bicarbonate (Ca(HCO3)2 ⇌ CaCO3 + H2O + CO2). Particulate and colloidal calcium
carbonate plays an important role in that it has the capacity to strongly adsorb a variety of
biologically active compounds, including humic acids and phosphates.
Figure 11. The nitrogen cycle
Figure 12. The phosphorus cycle
Equilibrium depends on pH; the solubility of orthophosphate acid increasing with pH.
2
Slow release of orthophosphate from pond sediments, particularly under reducing
conditions (caused indirectly through metabolism of anaerobic sulphur bacteria).
1
The drying out period for adequate mud mineralization is usually between five to ten days,
as evident by the appearance of cracks on the mud surface or by the ability of the pond
bottom to support a man's weight without subsiding (Vincke, 1985; Clifford, 1985; Wilson,
1987). For the culture of specific benthic food organisms, it is essential that the pond
bottom is not ‘bone’ dry; for example a drying period 7–10 days and 3 days is usually
recommended for the preparation of pond muds for the growth of “lab-lab” (algal mat
primarily composed of blue green algae and diatoms) and “lumut” (algae mat primarily
composed of filamentous grass-green algae) within brackishwater fish or shrimp ponds,
respectively (ASEAN, 1978). Although ponds are usually dried at the start of each new
culture cycle, in China fish ponds are normally dried for a 15–20 day period only every one
to three years (FAO, 1983). However, pond drying is not normally recommended for those
coastal and riverplain soils such as “cat's clay” and “mine overburn” which contain pyrite FeS2 and other sulphur containing minerals. Upon exposure to air these minerals oxidize
to form sulphuric acid and iron sulphate compounds (jarosite); the resultant “acid-sulphate”
soil is characterized by a very low pH (< 4) and yellow spots or streaks of jarosite (Coche,
1985). Other disadvantages often ascribed to pond drying include 1) loss in time otherwise
used for fish or shrimp production, and 2) additional labour and water cost (ie. cost of
draining and refilling the pond with water, including electrical pumping costs).
3.2.2.2 Liming
According to Thomaston and Zeller (1961) and Boyd (1986), for a freshwater pond to
respond properly to fertilization, the bottom mud must not be highly acidic and the surface
water should have a neutral-alkaline pH (7–8) and a total alkalinity and total hardness of
20 mg/l or more as calcium carbonate. Acidic muds strongly adsorb inorganic phosphates,
and pond food organisms (particularly phytoplankton) do not grow wellin an acidic
environment (pH5–6) or in water with a low base carbon and calcium concentration (Miller,
1976; Vincke, 1985; Fast, 1986; Boyd, 1986). However, these imbalances may be
corrected by applying quicklime (CaO) or limestone (CaCO3) to the pond bottom or water
column prior to the start of the culture cycle or pond fertilization programme. Boyd (1982)
lists three basic types of ponds that respond favourably to liming: 1) dystrophic pondswith
waters heavily stained with humic substances and muds with large stores of slowly
decaying organic matter (typical water quality: pH 5 – 6, alkalinity 1 – 5 mg/l CaCO3,
acidity 0 mg/l CaCO3), 2) ponds with waters of low pH and alkalinity because of
moderately acid muds and watershed soils (typical water quality: pH 5.5–7, alkalinity 3 –
15 mg/l CaCO3, acidity 0 mg/l CaCO3), and 3) dystrophic ponds with waters containing
mineral acidity resulting from acid-sulphate soils of watersheds (typical water quality: pH 2
– 4.5, alkalinity 0 mg/l CaCO3, acidity 10 – 250 mg/l CaCO3).
The beneficial effects of liming ponds can be summarised as follows:







Liming raises the pH and alkalinity of acid waters to desirable levels, establishing a
alkaline reserve or pH buffering system (Mortimer, 1954; Huet, 1975; Miller, 1976;
Boyd, 1982, FAO, 1983; Yamada, 1986).
By virtue of its effect on alkalinity, liming increases the availability of carbon for
photosynthesis (Mortimer, 1954; Miller, 1976; Boyd, 1982; Fast, 1986; Yamada,
1986).
Liming raises the pH of the mud bottom to desirable levels and consequently
reduces the capacity of the mud to adsorb plant nutrients such as inorganic
phosphates, thus increasing their bioavailabilityto pond food organisms (Mortimer,
1954; Huet, 1975; Miller, 1976; Boyd, 1982; FAO, 1983; Fast, 1986; Yamada,
1986).
By raising the pH of acidic sediments, liming creates a more favourable
environment for microbial growth and consequently accelerates the decomposition
and mineralization of organic matter within the sediment (Huet, 1975; Miller, 1976;
Boyd, 1982; Fast, 1986; Yamada, 1986).
By raising the alkalinity and hardness of water; liming serves as direct source of
soluble calcium for pond food organisms (Mortimer, 1954; Boyd, 1982; FAO, 1983).
Liming assists in the clarification of turbid waters by facilitating the flocculation and
precipitation of organic/clay colloids in suspension (including humic acids), there-by
improving light penetration for photosynthesis (Mortimer, 1954; Boyd and
Scarsbrook, 1974; FAO, 1983; Yamada, 1986).
Liming serves as a pond disinfectant, by killing fish parasites and their intermediate
hosts, animal competitors, and unwanted green plants (Mortimer, 1954; Huet,
1975; Miller, 1976; Boyd, 1982; FAO, 1983; Yamada, 1986).

By virtue of the above attributes, liming therefore, increases (all be it indirectly) the
natural productive capacity of freshwater ponds with acidic waters and low total
alkalinity and hardness (Boyd, 1982; Strumer, 1987). For example, Zeller and
Montgomery (1962) and Boyd and Scarsbrook (1974) reported increased live food
production (phytoplankton, zooplankton and benthic food organims) within fertilized
ponds which were pretreated with lime; liming increasing the effectiveness of the
fertilization strategy employed. A similar relationship exists for fish production
within such ponds; pretreating ponds with lime increasing the effectiveness of
inorganic fertilization with increased fish yields. For example, Arce and Boyd (1975)
and Hickling (1962) reported a 24.9% and 41.6% increase in Tilapia production,
respectively, within limed over unlimed ponds receiving inorganic fertilizer inputs.
However, it should also be mentioned that not all studies have demonstrated a
positive influence of liming on fish production (Swingle, 1947; Miller, 1976; Boyd,
1982). Thus on the basis of liming trials conducted within freshwater fish ponds in
Africa, Miller (1976) concludes that the use of lime in water of pH greater than 6.5
appears unnecessary. Similarly, with the exception of coastal acid-sulphate soils,
liming is not considered to be essential for saltwater pond preparation; seawater
exhibiting a strong buffering capacity and having a pH range between 7.5 to 8.4
(Sturmer, 1987).
According to Boyd (1982), the lime requirement for a fish pond should represent the
quantity of calcium carbonate required to raise the pH of the mud to 5.9 so that the base
unsaturation (proportion of acidic cations to total cations on particle exchanges sites) of
the mud will be 0.2 or less and the total hardness (and alkalinity) will be above 20mg/l.
Table 12 shows the recommended lime application rates for fish ponds as determined by
the Boyd technique. However, it should be remembered that the above relationship
between base unsaturation and pond alkalinity/hardness was determined for ponds in
Alabama, USA and relationships between mud pH and base unsaturation differ
geographically (Boyd, 1986).
Table 12. Estimated lime requirement (kg CaCO3/ha) needed to increase the total
hardness and alkalinity of pond water to 20mg/l or greater1
Mud pH
in water
5.7
5.6
5.5
5.4
5.3
5.2
5.1
5.0
4.9
4.8
4.7
1
7.9
91
126
202
290
340
391
441
504
656
672
706
Calcium carbonate required according to mud pH in buffered solution
7.8
7.7
7.6
7.5
7.4
7.3
7.2
7.1
182
272
363
454
544
635
726
817
252
378
504
630
756
882
1,008
1,134
404
604
806
1,008
1,210
1,411
1,612
1,814
580
869
1,160
1,449
1,738
2,029
2,318
2,608
680
1,021
1,360
1,701
2,041
2,381
2,722
3,062
782
1,172
1,562
1,548
2,344
2,734
3,124
3,515
882
1,323
1,765
2,205
2,646
3,087
3,528
3,969
1,008
1,512
2,016
2,520
3,024
3,528
4,032
4,536
1,310
1,966
2,620
3,276
3,932
4,586
5,242
5,980
1,344
2,016
2,688
3,360
4,032
4,704
5,390
6,048
1,412
2,116
2,822
3,528
4,234
4,940
5,644
6,350
Source: Boyd (1982)
2
7.0
908
1,260
2,016
2,898
3,402
3,906
4,410
5,040
6,552
6,720
7,056
2
Lime required (as CaCO3) is estimated from the pH of the pond muds beforeand after the addition of a buffer solution. The
mud sample for limerequirement measurement should be dried at room temperature by spreadingin a thin layeron a plastic
sheet. The dried mud sample is then groundusing a pestle and mortar and passed through a 20-mesh sieve
(0.85mmopenings) for pH analysis. The buffer solution is prepared by dissolving20g of p-nitrophenol, 15g of boric acid, 74g
of potassium chloride, and10.5g of potassium hydroxide in distilled water and diluting to one litrein a volumetric flask. Place
20.0g of the dried and ground mud sample intoa 100 ml beaker, adding 20ml of distilled water, and stir intermittently for one
hour. Measure the pH of the mud-water mixture with a glasselectrode while stirring. The value obtained is the mud pH.
Next,add 20.0ml of the prepared buffer solution to the mud-distilled watermixture and stir intermittently for 20 minutes. Set
the pH meter atpH 8.0 with a 1:1 mixture of buffered solution and distilled water,and then determine the pH of the muddistilled water-buffer solutionmixture while stirring vigorously. If the pH of the mud-distilledwater-buffer solution mixture is
below 7.0, repeat the analysis with10.0g dry mud and double the liming rate from the Table above (for adetailed description
of the method see Boyd, 1979).
Ideally, the relationship between pH and base unsaturation of muds should be determined
for every farm or region, and liming rates computed accordingly. A simple method for
determining the lime requirement of pond muds that does not require data on the
relationship between pH and base unsaturation has been developed by Pillai and Boyd
(1985); the liming rate (kg CaCO3/ha) is simply determined by measuring the pH change in
40ml of buffer solution (10g p-nitrophenol, 7.5g boric acid, 37g potassium chloride, and
5.25g potassium hydroxide dissolved and diluted to 1000ml with distilled water; the buffer
pH being adjusted to 8.00) caused by adding 20g of ground dried mud (particles <
0.85mm) and multiplying the observed pH change by 5600.
The above techniques for estimating lime application rates do not apply to acid sulphate
soils, since these sediments have both exchange and sulphuric acid acidity. Singh (1980)
recommends a soil tilling (pyrite oxidation) and leaching reclamation procedure, followed
by liming and inorganic/manure fertilization, for the management of acid sulphate soils. A
procedure for estimating the lime requirement of acid-sulphate soils is given by Boyd
(1979). Examples of lime application rates for aquaculture ponds suggested by other
workers are shown in Table 13.
For the composition and neutralizing value of commonly used liming materials see Boyd
(1979) and Tacon (1987a). Although the neutralising effects of quicklime (CaO) and slaked
lime (Ca(OH)2) on acid waters is higher and faster than that of agricultural limestone
(CaCO3), the latter is generally regarded to be the safest, cheapest and most effective
liming material for ponds (Boyd, 1982). On a general basis, liming materials should be
added 2 – 3 weeks prior to fertilization (Boyd, 1982; Miller, 1976), and applied by
spreading evenly over the pond bottom (in the case of empty ponds) or water surface. The
residual effects of liming depend on water exchange within the pond, and may last for
several years if water exchange is not excessive. For example, Boyd (1979) found that an
annual lime application rate of 25 percent of the initial dose of about 4400kg/ha agricultural
limestone was sufficient to maintain adequate water quality and mud pH for an eight year
period within annually drained fish ponds in Alabama, USA.
Table 13. Examples of suggested lime application rates for aquaculture ponds
a. Suggested liming rates for the treatment of low soil pH 1
Soil pH
4
4.5
5
5.5
6
6.5
1
2
Liming material (lbs/acre) 2
Carbonate of lime
Slaked lime
1487
1417
1320
1258
994
924
660
634
334
299
0
0
Caustic lime
994
898
634
466
239
0
Source: Clifford (1985)
1kg = 2.205 lbs, 1 ha = 2.47 acres
b. Suggested liming rates for pond muds based on pH and texture of muds
requirement (kg/ha of CaCO3)
Mud pH
4
4 – 45
4.6 – 5
5.1 – 5.5
5.6 – 5.0
6.1– 6.5
1
Heavy loams or clays
14,320
10,740
8,950
5,370
3,580
1,790
Sandy loam
7,160
5,370
4,475
3,580
1,790
1,790
1
Lime
Sand
4,475
4,475
3,580
1,790
895
0
Source: Schaeperclaus, 1933 (cited by Boyd, 1982)
c. Suggested liming guide for aquaculture ponds in Rwanda (Schmidt and Vincke,
1981)
Newly constructed ponds with acid water (pH 4–6.5): use of powdered agricultural
limestone at a rate of 1500–2000kg/ha by spreading on the dried pond bottom and
lightly tilling the lime into the mud surface layer, then filling pond with water.
Other ponds: monthly application of powdered limestone at a rate of 150–
200kg/ha.
For a review on the use of lime in African countries see Miller (1976).
d. Suggested liming guide for aquaculture ponds - general (Huet, 1975)
Liming pondwater: the use of up to 200 kg/ha/day of quicklime (CaO). Liming pond
bottom to control parasites: the use of 1000–1500kg/ha of quicklime (CaO) or
1000kg/ha of calcium cyanamide. Liming materials should be spread on pond
bottom which is still damp.
Liming pond bottom to improve the mud before using other fertilizers: the use of
200–400kg/ha of quicklime (CaO) provided that the pond is not acid. If the aim of
liming is to increase the pH and alkalinity of an acid pond, in principle 200kg/ha of
quicklime (CaO) is generally sufficient to raise the alkalinity by one unit.
e. Suggested liming guide for African catfish ponds (Viveen et. al., 1985)
Newly constructed ponds: use of agricultural lime at a rate of 200– 1500kg/ha and
mixing with the upper layer (5cm) of the dried pond bottom. Pond is then filled with
water (till 30cm) and left for one week prior to fertilization.
Used ponds: use of 100–150kg/ha quicklime (CaO) added to damp pond bottom to
eliminate pathogens, parasites and invertebrate predators. Pond is then left for a
7–14day period and then filled with water to a depth of 30cm, and pH of water
adjusted by adding agricultural lime.
f.
Liming rates employed for aquaculture ponds in China (FAO, 1983)
Liming pond water: use of quicklime (CaO) at a rate of 750–900kg/ha and 900–
1125kg/ha for ponds containing 6–7cm water and containing little silt and silt
respectively. For ponds containing a considerable amount of water (unspecified) an
application rate of 1875–2250kg/ha/ month quicklime is used.
g. Liming rates suggested for car ponds in Hungary (Horvath, Tamás and Tölg, 1984;
ADCP, 1984)
Nursery ponds: use of 200–500kg/ha of lime (CaO) on dried bottom for disinfection,
followed by aeration of pond bottom by tilling.
h. Liming rates suggested for Colossoma sp in Brazil (Woynarovich, 1986)
Nursery ponds: use of 150–300kg/ha of limestone (CaCO3) on dried bottom.
i.
Liming rates suggested for Macrobrachium rosenbergii in Panama (MIDA, 1984)
Newly constructed ponds: use of 500–1000kg/ha of limestone (CaCO3) on pond
bottom.
j.
Liming rates suggested for newly constructed rural fish ponds in Thailand (Edwards
and Kaewpaitoon, 1984)
Acidity of new pond is tested using litmus paper after introduction of water to a
depth of 10cm. For water pH 4.5–6: 500kg quicklime/ha For water pH 4–4.5:
1250kg quicklime/ha. After one day, the pond should be filled with water and the
acidity checked again.
3.2.3 Chemical fertilization of aquaculture ponds
Chemical fertilizers are applied mainly to increase the primary productivity of aquaculture
ponds. The chemical nomenclature and composition of the major single and multinutrient
chemical fertilizers used in aquaculture has been presented previously (Section 1.2 and
3.12; Tacon, 1987a).
3.2.3.1 Effect on pond productivity and fish/shrimp production
Chemical fertilizers act principally on the autotrophic and grazing food chain by directly
stimulating phytoplankton production within the pond (Hepher, 1962; McIntire and Bond,
1965; Hall, Cooper and Werner, 1970; Djajadiredji and Natawiria, 1965; Boyd, 1973; Miller,
1976; Guerrero and Guerrero, 1976; Cruz and Laudencia, 1980; Davidson and Boyd,
1981; Hepher and Pruginin, 1981; Bishara, 1978; Rubright et. al., 1981; Nailon, 1985; Olah
et. al., 1986; Pruder, 1986; King and Garling, 1986; Yamada, 1986). For example, the
studies of Hepher (1962) showed that the production of phytoplankton within chemically
fertilized fish ponds in Israel was four to five times higher than equivalent ponds receiving
no fertilizer input; the primary productivity of chemically fertilized ponds ranging from a
carbon uptake of 4–8g/m2/day during the summer (mid-day water temperature 25–30°C) to
2.5–5g/m2/day during spring and autumn (mid-day water temperature 20–25°C). According
to Schroeder (1978) over 90% of the total primary production is smaller than 40 microns in
size. As a consequence of their direct effect on phytoplankton production, chemical
fertilizers also indirectly augment the production of grazing zooplankton (McIntire and
Bond, 1962; Dendy et. al., 1968; Hall, Cooper and Werner, 1970; Lyubimova, 1974;
Rubright et. al., 1981; Torrans, 1986) and benthic food organisms (Ball, 1949; McIntire and
Bond, 1962; Sumawidjaja, 1966; Rubright et. al., 1981; Boyd, 1981). For example, Torrans
(1986) reports a standard zooplankton biomass range of 2–10g/m3 within inorganically
fertilized static fish ponds.
Although aquaculture production within chemically fertilized ponds will vary depending on
the feeding habit and density of the culture species stocked, considerable increases in fish
and shrimp production are possible (Table 14). For example, Schroeder (1978) reports
that the maximum fish yields attainable with no supplementary feeding (in earthen ponds
in Israel) are 1–5kg/ha/day and 10–15kg/ha/day for ponds receiving no fertilizer input and
chemical fertilizers, respectively; common carp, tilapia and silver carp polyculture at 4500–
9500 fish per hectare. Similarly, Horvath, Tamas and Tolg (1984) report a fish production
increase (mainly carp polyculture) within earthen ponds in Hungary of 11–25kg and 15–
30kg from a 200kg fertilizer input of superphosphate or ammonium nitrate, respectively.
However, as mentioned previously, the success of a chemical fertilization strategy will
depend upon the ability of the farmed fish or shrimp species to take advantage of the
increased primary productivity within the pond. Adult fish and shrimp species which can
feed directly on primary autotrophs, include: Phytoplankton - Silver carp
(Hypophthalmichthys molitrix), Indian carp (Catla catla), Tilapia (esculentus, aureus,
niloticus, kottae, mariae, galilaeus, leucostictus, mossambicus), Bighead carp (Aristichthys
nobilis); Benthic algae - Milkfish (Chanos chanos), Tilapia (mossambicus, guineensis,
melanotheron, niloticus), Mullet (Mugil cephalus), Rabbit fish (Siganus sp.) Rohu (Labeo
Rohita), Freshwater prawn (Macrobrachium dayanum, M. lanchesteri), Metapenaeid
shrimp (Metapenaeus ensis M. affinis, M. macleay), Penaeid shrimp (Penaeus vannamei);
Vascular aquatic plants - Grass carp (Ctenopharyn-godon idella), Tilapia (rendalli,
niloticus, Mossambicus, zillii), Wuchang fish (Megalobrama amblyocephala), Rabbit fish
(Siganus sp.) Rohu (Labeo rohita) and occasionally freshwater prawns (Macrobrachium
sp.). For a review of the natural feeding habits of the major cultivated fish and shrimp
species see Ling (1969), Wickins (1976), Von Westernhagen (1974), Bowen (1982),
Cremer and Smitherman (1980), Bishara (1979), Cruz and Laudencia (1980), Guerrero
and Guerrero (1976), Rubright et.al., (1981), Weidenbach (1982), Swift (1985), Horvath,
Tamas and Tolg (1984), Torrans (1986), King and Garling (1986), New (1987), Hunter,
Pruder and Wyban (1987), and Lilyestrom and Romaire (1987).
Table 14. Reported fish and shrimp production increases within chemically fertilized ponds
compared with non-fertilized control ponds
Production
increase (%)
Species
Tilapia
mossambicus)
(O.
Fertilizer used
Source
440
Phosphate
Vander Lingen (1967)
Tilapia sp. (hybrid)
82–222
Phosphate
Lazard (1973)
Tilapia sp.
214
Phosphate
Strum (1966)
Tilapia (O. niloticus)
340
Phosphate
George (1975)1
Tilapia
hybrid)
302–420
Phosphate
Hickling (1962)
174
0:8:2 (NPK)
Varikul (1965)
170
8:8:2 (NPK)
Varikul (1965)
Carp (C. carpio)
752–945
Phosphate:Ammonium
Sulphate
Hepher (1963)
Carp (C. carpio)
109
0:8:2 (NPK)
Swingle,
Gooch
Rabanal (1963)
&
Carp (C. carpio)
137
8:8:2 (NPK)
Swingle,
Gooch
Rabanal (1963)
&
Catfish (I. punctatus)
565
0:8:2 (NPK)
Swingle,
Gooch
Rabanal (1963)
&
Catfish (I: punctatus)
476
8:8:2 (NPK)
Swingle,
Gooch
Rabanal (1963)
&
Mullet (M. cephalus)
167
Phosphate
El Zarka
(1968)
Phosphate/Urea
Rubright et. al., (1981)
sp.
(male
Tilapia
mossambicus)
(O.
Tilapia
mossambicus)
sp(O.
Shrimp (P. stylirostris) 89
&
Fahmy
1 Cited by Hepher and Pruginin (1981)
3.2.3.2 Fertilizer application rates
It is generally accepted that inorganic phosphate-P and nitrogen-N are the two major
soluble nutrients normally limiting the algal productivity of aquaculture ponds; phosphate-P
and nitrogen-N generally being the first limiting nutrients (ie. most essential from a pond
fertilization viewpoint) within freshwater and brackishwater ponds, respectively (Boyd
1982, 1986; Miller, 1976; ASEAN, 1978; Vincke, 1985; Smith, 1984; Nailon, 1985;
Yamada, 1986; Strumer, 1987; Boyd and Minton, 1987). It must be emphasized at the
outset that no two ponds are alike and that a fertilization programme developed or
recommended for one location may be totally unsuitable for another, the response of a
fertilization programme depending on the pond's morphology, hydrology, environment,
bottom sediment, and water quality, on the aquaculture species cultured and the fertilizer
used, and the fertilizer application method and rate employed (Yamada, 1986; Boyd,
1986). Clearly, every farm must be considered as being unique, and a personalised
fertilization programme developed accordingly. However, despite this rather daunting
picture, some generalisations can be made regarding pond fertilization.
According to Hepher (1963, 1967) there is no biological or economical justification of
applying higher fertilizer dosages than 0.5mg phosphate-P/l or 1.4mg nitrogen-N/l for
freshwater ponds in Israel; applications higher than these levels generally being fixed as
precipitated phosphates or lost to the environment as gaseous ammonia. The above levels
are equivalent to a fertilizer application rate of 60kg/ ha single superphosphate (11kg
P2O5/ha) and 60kg/ha ammonium sulphate (13kg N/ha) applied at 2-weekly intervals (0.8–
1.0m water depth, 8–10,000 m3 water/ha). This fertilizer application rate is currently the
standard dose for fertilizing semi-intensive ponds in Israel with densities of 2000–3000
fish/ha (Hepher and Pruginin, 1981). Boyd (1982) and ASEAN (1978) suggest chemical
fertilization strategies to maintain soluble nitrogen and orthophosphate at 0.1–0.5mg P/l
(Boyd, 1982) and 0.95mg N/1 and 0.11mg P/l (ASEAN, 1978) within freshwater and
brackishwater aquaculture ponds, respectively. The beneficial effect of using nitrogen
based fertilizers within freshwater ponds has met with variable results (Hickling, 1962;
Hepher, 1963; Miller, 1976; Boyd and Sowles, 1978; Boyd, 1982; Vincke, 1985; Yamada,
1986); Vincke (1985) suggest that the continued use of N-based fertilizers may not be
necessary within tropical freshwater fish ponds due to the high rate of N fixation by freeliving bacteria and blue-green algae within these ponds. Example of fertilizer application
programmes which have been tested and proven under pond farming conditions are
shown in Table 15.
Although various precise chemical methods exist for estimating the primary productivity of
a water body (Boyd, 1979, 1982; Schroeder, 1978; Davidson and Boyd, 1981; Olah et.al.,
1986), the effectiveness of a pond fertilization programme can be quickly determined by
measuring the turbidity (ie. transparency) of the water body by means of a Secchi disk.
This simple and practical method is based on the assumption that the main source of
turbidity within a fish or shrimp pond is the abundance of phytoplankton (Barica, 1975;
Almazan and Boyd, 1978; Boyd, 1979, 1982). Stickney (1979) and ASEAN (1978)
recommend a Secchi disk visibility of 30cm to achieve and maintain proper fertilization;
readings above (>35cm) and below (<25cm) this level indicating under and excessive
phytoplankton production, respectively. If a Secchi disk is not available, the rule of thumb
is to submerge one's arm to the elbow; if one is just able to see the ends of ones fingers
the water should be productive enough (FAO, 1981). The Secchi disk method is not
suitable for shallow brackishwater ponds intended for benthic algal production or for use
within turbid water bodies containing high concentrations of suspended clay particles.
3.2.3.3 Factors influencing the action of chemical fertilizers
Apart from the beneficial effect of liming (section 3.2.2.2) the following factors are known to
influence the success or not of a chemical fertilization feeding strategy;
1. Sunlight: In the presence of adequate inorganic nutrients, primary production
reaches a maximum value set by the amount of solar energy penetrating the pond
water (Schroeder, 1978, 1980; Wohlfarth and Schroeder, 1979). Although Tamiya
(1957) and Hepher (1962) state that the maximum primary productivity within
tropical waters is equivalent to about 10g of carbon fixed as algae/m2/day, Talling
et.al., (1973) have suggested that the upper limit for gross primary productivity is
17.8g of carbon fixed/m2/day or the equivalent release of 47g of oxygen (in general
2.6g of oxygen are produced for every gram of carbon fixed during photosynthesis;
Cassinelli et.al., 1979; Pruder, 1986). According to Pimentel and Pimentel (1979)
about 0.03% of the light reaching an aquatic ecosystem is fixed by phyto-plankton
and aquatic plants, and is calculated to be approximately 4 × 106 kcal/ha/year or
about one third of that fixed in terrestrial habitats.
From the above it follows that increasing water depth, water turbidity1 (caused by
suspended clay particles), over-cast skies and shading will reduce the amount of light
reaching the green autotrophs, and consequently will limit the primary production capacity
of a pond (Miller, 1975; Boyd, 1986). Furthermore, the continued application of chemical
fertilizer beyond a certain level will not result in increased primary productivity; the amount
of solar energy penetrating the pond water dictating the upper limit for autotrophic
production (Hepher, 1962; Schroeder, 1978, 1980).
1
The detrimental effect of water turbidity resulting from clay suspensions may be reduced by treating the pond water with
aluminium sulphate or gypsum (Boyd, 1986), barnyard manure (2–3 applications of 1 ton/acre at 3-week intervals; Boyd and
Snow, 1975), or a cotton-seed meal superphosphate mixture (3 : 1, 100 lbs/acre; Swingle and Smith, 1974).
Table 15 Examples of pond fertilization feeding strategies
FRESHWATER PONDS
1. Freshwater prawn (M. Lanchesteri/M. Lanceifrons montalbanense) and Tilapia
(nilotica, mossambica) polyculture - Philippines (Guerrero and Guerrero, 1976):
 Biweekly application of 50kg/ha ammonium phosphate 16:20:0 (NPK) using
underwater platforms, water depth 0.6–0.7m
 See also Guerrero (1981) for tilapia monoculture using 50kg/ha ammonium
phosphate to maintain productivity, and stocking fish two weeks after initial
fertilization.
2. Tilapia (nilotica) fingerling production - Rwanda (Schmidt and Vincke, 1981):
 Monthly application of 40kg/ha superphosphate (18%) and 20–40 kg/ha
ammonium sulphate or 10–20kg/ha urea and 100kg/ha agricultural
limestone
3. Tilapia growout - Ivory Coast (Lazard, 1973; cited by Miller, 1976):
 Monthly application of 60kg/ha triple superphosphate; monthly dose given
in two equal applications in baskets suspended in the surface water
4. Carp (C. carpio) fingerling production - Malagasy Republic (Vincke, 1970; cited by
Miller, 1976):
 Biweekly application of 20–40kg/ha triple superphosphate and 40– 80kg/ha
ammonium sulphate given every 2–3 weeks
5. Tilapia growout - Zambia (Strum 1966; cited by Miller, 1976):
 Monthly application of 56kg/ha double superphosphate (38% P2O5)
6. Carp (C. carpio, H. molitrix) and Tilapia (aurea or hybrid) polyculture - Israel
(Hepher, 1962):
 Biweekly application of 60kg/ha superphosphate (18%) and 60kg
ammonium sulphate
7. Carp nursery ponds - Hungary (Horvath, Tamas and Tölg, 1984):
 After pond drying and disinfection with lime, pond half filled (5–7 days
before fish stocking) with water and 150–200kg/ha ammonium nitrate or
carbamide added. Half of the application to be added during pond filling and
the remainder given in two applications after the first and second week of
nursing. Phosphorus should be added in a semi-dissolved state at 100kg/ha
when flooding of the pond occurs
8. General freshwater fish - Alabama USA (Boyd and Snow, 1975):
 Eight to twelve periodic applications per year of 45kg/ha 20:20:5 (NPK,
granular compound fertilizer), applied on to under-water platforms; first
application, followed by two applications at biweekly intervals, three
applications at triweekly intervals, and five applications at monthly intervals
 Subsequent studies have shown that nitrogen fertilizers may be greatly
reduced or omitted without reducing fish production (Boyd and Sowles,
1978)
 Dobbins and Boyd (1976) also found that potassium fertilizers are generally
unnecessary and that the standard phosphorus fertilization rate of 9kg
P2O5/ha/application could be reduced by half without significantly
decreasing fish production
 two to three weekly application of 6.6kg/ha ammonium polyphos-phate
solution (liquid fertilizer; 10:34:0 NPK; density 1.4g/ml; Davidson and Boyd,
1981)
9. Milkfish (C. chanos), Tilapia (T. nilotica) and Snakehead (O. striatus) polyculture Philippines (Cruz and Laudencia, 1980):
 Biweekly application of 50kg/ha ammonium phosphate (16:20:0, NPK)
10. General freshwater fish - China (FAO, 1983):
 Application of compound fertilizer (4:4:2, NPK) to maintain concentration of
0.9, 0.9 and 0.45mg/l respectively
11. General freshwater fish - Brazil/Hungary (Woynarovich, 1985):
 Biweekly application of 15kg/ha superphosphate (18%) and 30kg/ ha
ammonium nitrate
BRACKISHWATER PONDS
12. Shrimp (Penaeus stylirostris) growout - USA (Rubright et.al., 1981):
 Application of 15.7kg/ha pelletised urea (45:0:0) and 6.7kg/ha triple
superphosphate 19 days before shrimp stocking, and again 7 days after
stocking
13. Shrimp (Penaeus sp.) growout - Ecuador/Philippines (Clifford, 1985):
 Quotes initial application (while filling the pond) of 16.8– 22.4kg/ha urea and
1.1–5.6kg/ha triple superphosphate, followed by weekly application of 2.2–
5.6kg/ha urea and 1.1–2.2kg/ha triple superphosphate (application methods
- platforms, suspended perforated bags or dumping into intake water)
14. Shrimp (Penaeus sp.) growout - USA (Colvin, 1985):
 Quotes Parker et.al., (1974) who used weekly applications of 45kg/ha urea
once the shrimp reached 20mm in length, together with a 25% protein
pelleted shrimp diet
15. Shrimp (Penaeus sp.) growout - Ecuador (MIDA, 1985):
 Quotes substitution of pelleted feeds in Ecuador with weekly applications of
20kg/ha urea and 7kg/ha P2O5, final shrimp density 1.5–2/m2
16. Shrimp (Penaeus sp.) growout - Mexico (unpublished data):
 Initial application of 15–35kg/ha urea and 5–12kg/ha P2O5, followed by
monthly applications depending on water productivity
17. Shrimp (Penaeus sp.) growout - Brazil (unpublished data on commercial sector):

Initial application of 10–150kg/ha urea (mean 25kg) and 5–60kg/ ha triple
superphosphate (mean 15kg); followed by monthly applications depending
on water productivity
18. Mullet (Mugil capito) growout - Egypt (Bishara, 1979):
 Monthly applications of 20kg/ha superphosphate or 18kg/ha superphosphate plus 18kg/ha ammonium nitrate
19. Red drum (S. ocellatus) nursery - USA (Colura, 1987):
a. Fertilization schedule used at the GCCA/TPWD John Wilson Marine Fish
Hatchery in Corpus Christi, Texas. All fertilizer rates are calculated on a per
hectare basis:
Day
1
3
6
8
12
14
16
22
24
30
38
Treatment
Fill pond to 1/3 volume
Add 12L phosphoric acid and 28L ammonium nitrate (33%N)
Spread 455kg of cottonseed meal (CSM) over water surface
Finish filling pond
Add 12L phosphoric acid and 28L ammonium nitrate
Stock approximately 750,000 fry
Spread 114kg CSM over water surface
Add 12L phosphoric acid and 28L ammonium nitrate
Spread 114kg CSM over water surface
Spread 114kg CSM over water surface
Spread 114kg CSM over water surface
b. Fertilization schedule used at the TPWD Perry R. Bass Marine Fisheries
Research Station, Palacios, Texas. All fertilizer rates are calculated on a
per hectare basis:
Day
1
3
7
10
12
15
17
19
21
23
24
25
Treatment
Spread 282kg CSM on dry pond bottom; fill to approximately 100cm deep
Continue filling. Add 9L phosphoric acid and 4.6kg urea (45%N)
Spread 31.3kg CSM
Spread 31.3kg CSM, stock fry
Spread 31.3kg CSM, add 3L phosphoric acid and 4.6kg urea
Spread 31.3kg CSM
Spread 31.3kg CSM
Spread 31.3kg CSM, add 3L phosphoric acid and 4.6kg urea
Spread 31.3kg CSM
Spread 31.3kg CSM
5.7kg/ha salmon starter diet
Spread 31.3kg CSM, add 3L phosphoric acid and 4.6kg urea
20. ‘Lab-Lab’ (benthic blue-green algal complex) culture for milkfish (C. chanos)/shrimp
ponds - General (ASEAN, 1978):
 Pond bottom should be first dried for a 7–10 day period (not bone dry).
Dried chicken manure (insecticide free) should be applied to dry pond
bottom at the rate of 350kg/ha to increase the organic matter content of
pond sediment; lab-lab growth being directly related to the organic matter
content of the mud - growth being very abundant in soils with 16% organic
matter or more. In the absence of chicken manure (or other animal
manures), chemical fertilizers may be applied at the rate of 50–100kg/ha
18:46:0 (NPK) or 100–150kg/ha ammonium phosphate (16:20:0, NPK).
Immediately after fertilization 3–5cm of water is introduced into the pond.
After one week, the same amount of fertilizer is applied and the water level
is raised to 10–15cm. The fertilization is repeated after the second week
and the water level is raised to 20–25cm. Additional water is added to the
pond as necessary to make up for see-page and evaporation losses. Many
farmers recommended fertilization every 7 days throughout the fish or
shrimp culture period. For further details see Padlan, Ranoemihardjo and
Hamami (1975).
 Yamada (1986) quotes the ‘lab-lab’ fertilization programme of Ballesteros
and Mendoza (1976) for milkfish culture in the Philippines: Initial application
of 100–200kg/ha 18:46:0 (NPK) onto dry pond bottom, and then allowing
water to enter the pond. Additional fertilizer applications of 50–100kg/ha
18:46:0 (NPK) every 10–15 days up to one week before stocking. One
week after stocking further application of 15–25kg/ha 18:46:0 (NPK),
repeating this dosage every 10–15 days until harvest.
 Djajadiredja and Poernomo (1973) quote a fertilization programme for the
production of ‘kelekap’ (benthic algal complex) for milk-fish ponds in
Indonesia: ponds are first drained and the mud thoroughly tilled so as to
make it as soft and fine as possible. Fertilizer application of 130kg/ha urea,
65kg/ha triple superphos-phate and 1000kg/ha rice chaff (locally known as
‘sekam’) by scattering evenly over the moist pond bottom. Immediately after
fertilizer application water level in the pond raised to 3–10cm. After a good
growth of benthic algae is noticed, water level raised to normal level of 30–
40cm and fish stocked. Djajadiredja and Natawiria (1965) observed that
8.8–28.1 tons (average 15.6 ton /ha) of ‘kelekap’ could be produced in 2
weeks with an application of 500kg/ha urea. However, chemical fertilizers
are rarely used for benthic algal production in Taiwan; preference being rice
bran and night soil (Chen, 1973).
 Proce dure for growing ‘lab-lab’ can also be used for freshwater fish ponds,
using an initial fertilization regime of 50kg/ha 16:20:0 (ammonium
phosphate, NPK), 22kg/ha 46:0:0 (urea, NPK), and chicken manure at
2000–2500kg/ha (Bautista, 1982; Oandasan, 1982).
21. ‘Lumut’ (benthic grass green flamentous algal complex) for milkfish (C. chanos) /
shrimp ponds - General (ASEAN, 1978):
 Soft mud bottoms with a pH 6.8–7.5 favour growth of ‘lumut’. Pond should
first be dried for a 3 day period, and sufficient water allowed to enter the
pond to moisten the soil. Moist bottom is then seeded with long filaments
from older or existing plants (it usually takes 2–4 weeks from planting until
the pond is ready for stocking). After seeding the pond is flooded to 30cm,
and 3–7 days later is fertilized with ammonium phosphate (16:20:0, NPK) at
a rate of 18–20g/m3 water, applied by broadcasting or by dissolving from a
platform placed 10cm below the water level. After one week the water level
raised to 40cm, and thereafter weekly applications of fertilizer given at a
rate of 9–10g/m3 water until 6 weeks before the crop is harvested. Rows of
twigs and small branches should be inserted into the mud bottom (lines 6–
15m apart) so as to minimise the destructive dis lodging action of wind and
waves on the ‘lumut’. With adequate wind breaks the water can be
maintained at a depth of 60cm.
2. Water exchange: For the beneficial effects of liming and chemical fertilizers to be
realized in the form of increased phytoplankton production it is essential that the
retention time of water in the pond be at least three to four weeks (equivalent to a
pond water exchange rate of 5%/day). Water exchange rates greatly in excess of
this will result in fertilizer and liming nutrients being flushed out of the pond before
they can be used (Boyd and Snow, 1975; Miller, 1976; Boyd, 1986). Excessive
water exchange rates may be a major problem in the tropics during the rainy
season.
3. Water chemistry: In waters with high calcium concentrations (hard water) and
elevated pH, the phosphate applied in fertilizers may be rapidly lost from the water
through precipitation as insoluble calcium phosphate, thus rendering it unavailable
to the primary autotrophs (Boyd, 1982). It follows therefore that phosphate fertilizer
application rates should be higher within hard waters of high pH than in softer
water with a more moderate pH (Boyd, 1986). In view of the above relationship,
phosphate fertilizers should never be applied at the same time or within one week
of liming (Viveen et.al., 1985).
4. Natural soil fertility: Ponds on fertile pasture soils require lower fertilizer application
rates than infertile woodland soils (Boyd, 1976). Similarly, rich alluvial soils with a
high organic matter content require lower fertilizer application rates than infertile
sandy loam soils for the growth of benthic blue-green algae (‘lab-lab’) within
brackishwater fish ponds (Tang and Chen, 1967; ASEAN, 1978).
5. Previous pond management: Newly constructed ponds generally require higher
initial fertilizer application rates than ponds with a history of fertilization and
accumulated bottom sediments (Hickling, 1962; Hepher, 1963; Swingle, 1965;
Boyd, 1986).
6. Aquatic weed infestation: Large populations of aquatic macrophytes will compete
with phytoplankton for available nutrients and sunlight, resulting in reduced
phytoplankton production (Boyd, 1982; Miller, 1976; Boyd, 1986). Weed infestation
may be controlled through liming, mechanical cropping, or through the use of
herbivorous fish species such as grass carp (C. idella), Tilapia (T. rendalli,
niloticus, mossambicus, zillii) or rabbit fish (Siganus sp.).
7. Algal taxonomic composition: Although chemical fertilization stimulates algal
productivity, the algal taxonomic composition is generally unpredictable (Boyd,
1986). Recommended dissolved nutrient concentrations favouring predominance
and growth of specific algal groups include: diatoms - 20–30:1, N:P (ASEAN,
1978); 10–20:1, N:P (Clifford, 1985); phytoflagellates - 1:1, N:P (ASEAN, 1978),
phytoalgal
plankton (general)
Bacteria (general)
- 4:4:1, N:P:K (Hora and Pillay, 1962)
- 4:1, N:P (Swingle and Smith, 1939; Nailon, 1985)
- 42:75:1, C:N:P (Hepher and pruginin, 1981)
- 50:10:1, C:N:P (Biomass composition; Edwards, 1982)
- 100:5:1, C:N:P (Growth medium, Edwards, 1982)
8. Fertilizer solubility: A fertilizer will only be effective if it is soluble. Although this is
not generally a problem for nitrogen based fertilizers (the majority being very
soluble), phosphate fertilizers vary in solubility depending on their particle size and
chemical composition (Table 16; Miller, 1976; Boyd, 1979; Hepher and pruginin,
1981). In this respect, liquid fertilizers (if available) are recommended over granular
and powdered fertilizers due to their faster solubilization and more uniform
distribution of nutrients in the water column (Musig and Boyd, 1980; Davidson and
Boyd, 1981).
Table 16. Percentage dissolution of phosphorus and nitrogen from selected
fertilizers after settling through a 2-metre water column at 29°C 1 2
Fertilizers
Superphosphate
Triple superphosphate
Monoammonium phosphate
Diammonium phosphate
Sodium nitrate
Ammonium sulphate
Ammonium nitrate
Calcium nitrate
Nutrient solubility (%)
Phosphorus
Nitrogen
4.6
5.1
7.1
5.1
16.8
11.7
61.7
85.9
98.8
98.7
1
Source: Boyd (1982)
The above solubilities are specific for the study in question:solubility also varying with fertilizer particle size and
water quality
2
9. Fertilizer application method and frequency of application: The fertilizer application
method used can have a profound effect on the success of a pond fertilization
regime. This is particularly true for granular and powdered phosphate fertilizers,
which if allowed to come into direct content with the pond bottom will become
rapidly adsorbed by the soil particles and so rendering the phosphate unavailable
to the planktonic algae. To overcome this difficulty, phosphate fertilizers should be
either dissolved in water prior to distribution or applied within floating perforated
cannisters, suspended perforated sacks or by placing onto underwater platforms
(Figure 13). The latter application methods rely on the gradual dissolution and
distribution of the fertilizer by wave action and water circulation within the pond; it
follows therefore that such devices should not be placed near the pond outlet (Van
der Lingen, 1967; Vincke, 1970; Boyd and Snow, 1975; Davidson and Boyd, 1981;
Viveen et.al., 1985; Boyd, 1982; Sanchez and Quevedo, 1987). However, it should
be emphasised that the fertilization of brackishwater ponds for the production of
benthic algae (ie. milkfish ponds) is radically different from that of freshwater ponds
where the main aim is to produce planktonic algae (Chen, 1973; Djajadiredja and
Poernomo, 1973; ASEAN, 1978). For the preparation of ponds for benthic
production fertilizers are applied directly onto the exposed and dried pond bottom
(Table 15).
For the maintenance of the pond primary productivity, fertilizers should be applied on a
‘little and often’ basis, preferably at weekly or biweekly intervals throughout the culture
cycle; the residual effect of an applied fertilizer dosage lasting for only two to four weeks
depending the water management strategy employed (Hepher, 1963; Miller, 1976; Boyd
and Snow, 1975; Hepher and Pruginin, 1981; Viveen et.al., 1985; Vincke, 1985; Boyd,
1982).
a) Underwater platform
1
b) Perforated floating can or
basket
c) Suspended perforated sack
Figure 13. Mechanical fertilizer application methods
1
The base of the platform should be 15–20cm below the water surface, andlocated near the pond water inlet or at the end of
the pond from which theprevailing wind comes. A single platform is sufficient for ponds up to 7hawhen plankton is grown.
Suggested platform top sizes for ponds of differentsizes include:
Pond area
(ha)
1
2
3
4
Platform top
dimensions (m)
0.85 × 0.85
1.25 × 1.25
1.50 × 1.50
1.70 × 1.70
5
6
1.90 × 1.90
2.10 × 2.10
7
2.25 × 2.25
Source: ASEAN
(1978)
3.2.4 Organic fertilization of aquaculture ponds
Organic fertilizers are applied mainly to stimulate the heterotrophic food chain of
aquaculture ponds. Although virtually all biological materials can be considered as
potential organic fertilizers, the commonest fertilizer used in aquaculture is animal or
farmyard manure (ie. farm animal faeces, with or without urine and bedding material).
Apart from being a readily available and inexpensive commodity, animal excreta
represents a nutrient packed resource containing 72–79% of the nitrogen and 61–87% of
the phosphorus originally fed to the animal (Taiganides, 1978). The average nutrient
composition of animal manures and other commonly used organic fertilizers has been
presented previously (Section 3.13; Tacon, 1987a). However, it must be emphasised at
the outset that the nutrient composition of animal manure is highly variable (depending on
the diet of the animal, the age and species of the animal, the type and proportion of
bedding material present, and the handling and treatment of the manure prior to usage),
and consequently each manure source must be considered as being unique and
chemically analysed accordingly. Sadly, the majority of published aquaculture production
trials involving the use of animal manures rarely report nutrient analyses of the ‘pig’,
‘poultry’ or ‘cattle’ manure used, the presence or not of bedding material, or whether the
quantities of manure applied to the pond were on a dry or fresh weight basis.
3.2.4.1 Effect on pond productivity and fish/shrimp production
In contrast to chemical fertilizers which act directly on the autotrophic food chain, organic
fertilizers act mainly through the hetero-trophic food chain by supplying organic matter and
detritus to the pond ecosystem; the manure serving principally as a substrate for the
growth of bacteria and protozoa, which in turn serve as a protein rich food for other pond
animals, including the cultured fish or shrimp (Figure 14). Whereas autotrophic production
within fertilized ponds is limited by available solar energy (Table 17), heterotrophic
production will depend upon the carbon and nitrogen content of the added manure and its
consequent susceptibility to microbial decomposition (Schroeder, 1978, 1980; Wohlfarth
and Schroeder, 1979). The C:N ratio of the applied manure will determine its rate of
bacterial decomposition in water and hence the time lag between application and
increased heterotrophic pond productivity; manures with a low C:N ratio (< 50; animal
manures, green weeds, grass, oilseed meals) being more rapidly decomposed by bacteria
than wastes with a high C:N ratio (> 100: straw, sugar cane bagass, sawdust; Tacon,
1987a, Sturmer, 1987). Schroeder (1980) suggests that the ideal C:N ratio for a bacterial
growth medium is about 20:1. It follows from the above that the smaller the particles of
organic matter the faster will be the colonization and decomposition by bacteria and
protozoans (Geiger, 1983); for example, fresh animal manure readily disintegrates in water
into colloidal particles. Schroeder (1980) estimates that the aerobic digestion of organic
matter by bacteria fixes about 20–50% of the substrate carbon into new bacterial biomass;
the yield of bacterial biomass obtained by aerobic digestion being about 10 times higher
than by anaerobic digestion (McCarty, 1972). According to Cassinelli et.al., (1979) for each
gram of organic matter decomposed, 1.2g of oxygen is consumed, and that for each gram
of carbon fixed during photosynthesis, 2.6g of oxygen is produced. These authors
concluded that the major source of oxygen to a shrimp pond was derived through algal
photosynthesis and that the major oxygen sink was algal and bacterial respiration (cited by
Pruder, 1986).
Figure 14. Fate of applied organic fertilizer in aquatic systems (adapted from Edwards,
1982; Delmendo, 1980 and Moore, 1986)
Table 17. Primary productivity and fish yields attainable within chemically fertilized and
manured ponds in Israel 1
Fertilizer input
Control - no input
Chemical fertilizers 2
Chemical fertilizer + organic manure 3
1
Primary productivity
(kg/ha/day)
6 – 12
30 – 60
30 – 60
Fish yield
(kg/ha/day)
1–5
10 – 15
32 (max)
For standing water ponds receiving no supplemental feeds (Schroeder, 1980)
Ammonium sulphate and superphosphate applied once every 2–3 weeks at60kg/ha
3
Manure application 6 days/week, at a daily dry organic matter loadingrate equivalent to about 3% of the fish biomass (field
dry chicken manureat a rate of 100kg organic matter/ha/day).
2
The beneficial effects of organic fertilization on natural pond productivity are well illustrated
by the studies of Schroeder (1980) and Rappaport, Sarig and Bejerano (1977), and their
results are summarised in Table 18. For additional information on the stimulatory effect of
manure on pond biota productivity see Tang (1970), Noriega-Curtis (1979), Olah et. al.,
(1986), ASEAN (1978), Malecha et. al., (1981), Lee and Shleser (1984), Barash and
Schroeder (1984), Wyban et. al., (1987), Garson, Pretto and Rouse (1986), and Zhang,
Zhu and Zhou (1987).
Intense organic and chemical fertilization of aquaculture ponds has resulted in fish and
shrimp yields as high as 5–10 tons/ha/year or 15–32 kg/ha/day with no supplementary
feeding (Fish- Tang, 1970; Schroeder, 1974, 1980; Schroeder and Hepher, 1979; Moav et.
al., 1977; Wohlfarth, 1978; Buck, Baur and Rose, 1978; Delmendo, 1980; Nash and
Brown, 1980; Edwards, 1980; Maramba, 1978; Djajadiredja and Jangkaru, 1978; ADCP,
1979; FAO, 1983; Vincke, 1985; Zweig, 1985; Plavnik, Barash and Schroeder, 1983;
Behrends et. al., 1983; Shrimp- Wyban et. al., 1987, Lee and Shleser, 1984). However,
these high production levels can only be achieved by using appropriate management
controls, and paying particular attention to fish/shrimp stocking density and species
selection (Schroeder, 1978; Wyban et. al., 1987). For example, Schroeder (1978)
correlated fish yields in ponds receiving only cattle manure and chemical fertilizers with
stocking density and found a linear relationship up to 9300 fish/ha (ie. the carrying capacity
of the pond; Figure 15). For each fish stocked, up to 9300 fish/ha, an annual yield of
0.75kg fish was obtained (as compared with an annual yield of 1kg for fish ponds
employing conventional pelleted feeds; Hepher and Schroeder, 1974). These results also
indicated an efficient manure conversion efficiency into new fish tissue; for every kg of fish
produced, approximately 3–3.5kg of manure dry matter was used (conversion efficiency
cited by Hepher and Pruginin, 1981). Wohlfarth and Schroeder (1979) report a conversion
efficiency of 2.7 and 3.5 for cattle and chicken manure for manuring trials conducted at
Dor, Israel, with a polyculture of common carp, silver carp, tilapia and grass carp. By
contrast, Garson, Pretto and Rouse (1986) report a shrimp (P. vannamei/ P.stylirostris)
conversion efficiency of 17 and 20 for chicken and cow manure, respectively (conversion
efficiencies calculated on a manure dry weight basis and for whole shrimp). Recalculation
of the data of Wyban et. al., (1987) with shrimp (P. vannamei) ponds receiving only feedlot
cattle manure shows a conversion efficiency (dry manure:whole shrimp) of 21 and 11 for
shrimp at stocking densities of 5/m2 and 15/m2, respectively; these authors also reported
that the carrying capacity of their manured ponds receiving 1800 kg feedlot
manure/ha/week was equivalent to about 1700 kg shrimp/ha.
Table 18. (a) Standing crops of phytoplankton, zooplankton, chironomid worms and
bacteria in manured and non-manured ponds with or without fish in Israel 1
Natural food organism
Phytoplankton (gDM/m3) 2
Zooplankton (gDM/m3) 3
Chironomids (100's/m 2)
Bacteria (1000's/ml) 4
1
Without fish
Manured
Non-manured
0.2–4.3
0.06
0.3–42.4
0.06
79–215
1–7
17–27
-
Manured
0.3–1.4
0.1–1.0
1–4
1.6–6.7
With fish
Non-manured
0.06–0.2
0.06
0–2
0.7–4.3
Source: Schroeder (1980) - water temperature 9–15°C, using cowshedmanure and a common carp, tilapia and silver carp
polyculture
2
Phytoplankton retained on a 50 micron net, grams dry weight/m 3
3
Zooplankton retained on a 150 micron net, grams dry weight/m 3
4
Bacteria concentration within the pond water column (for pond bottomswith an organic matter content greater than 1%, the
bacterialconcentration is 100–1000 times higher on the pond bottom than in theoverlying water column; Schroeder, 1978).
(b) Natural food organisms found in water and bottom soil of manured and non-manured
fish ponds in Israel 1
Manure input
Chicken droppings 2
Liquid cattle manure 3
Coral manure 4
Chemical fertilizer 5
Control - no input
Phytoplankton
(1000's/ml)
16.4
5.6
3.0
4.6
2.5
Rotifers
(No/ml)
1000
867
247
340
170
Chironomids
(No/500cm2)
340
82
38
43
59
1
Source:
Rappaport,
Sarig
and
Bejerano
(1977)
Dried manure allowed to stand covered with water for 7 days, and appliedat a rate of 5kg dry matter/ha/day
3
Dung
and
excreta
containing
about
10%
dry
matter,
application
as
forchicken
droppings
4
Fresh cow dung, also containing remnants of feed and coarse bedding,treated as for poultry droppings
5
20kg ammonium sulphate and 15kg superphosphate/ha/week.
2
Figure 15. Relationship between polyculture stocking density and fish yield in standing
water earthen ponds receiving fertilizer inputs only (Schroeder, 1980)
If maximum benefit is to be gained from the wide variety of live food organisms available
within a well fertilized pond (ie. phytoplankton, zooplankton, bacterial enriched detritus,
macrophytes, benthic algae and animals) it is essential that these ponds be stocked with
fish and/or shrimp with diverse feeding habits (Stickney, 1978; Schroeder, 1980; Wohlfarth
and Schroeder, 1979; FAO, 1983; Vincke, 1985; Malecha et. al., 1981; Zweig, 1985). Fish
polyculture strategies date back to the Chinese Tang Dynasty (7th centuary A.D; Zweig,
1985) and in China rest on three basic principles (FAO, 1983):



“complete use of the pond, both in depth, from the surface to the benthic zone and
over its entire surface area;
complete use of all types of natural food present in the pond: phyto- and
zooplankton, benthos, aufwuchs, detritus, aquatic plants, and
taking advantage of mutual benefits while avoiding competition for food. 1 Several
different species are therefore reared together in the fattening pond. Depending on
the type of food available locally, one or two of the main species of Chinese carps
are chosen: silver, bighead, grass, black or mud. They are then combined with
complementary secondary species on the basis of the principles set out above and
the ecological requirements of the species considered, for example:
i.
since the droppings of the grass carp are rich in undigested plant fibres,
they help the development of plankton which feeds silver and bighead carps
;
ii.
to control molluscs, 75–100 black carps/ha are added to the pond, while, to
control small fish and red shrimp, 450–600 carnivorous fish may be added,
if the pond is drained annually;
iii.
the common carp scours the bottom of the pond to obtain its nourishment
and this helps aerate the sediment, oxidize organic matter, recycle minerals
and finally encourages the development of plankton and the growth of
plankton-feeding species, and
iv.
nevertheless, competition may develop between the common carp and the
mud carp, the silver and bighead carps, or the silver and mud carps, which
makes it necessary to limit the number of one or the other of these species
(common carp: 150–225kg/ha; silver carp: 300–450 kg/ha)”.
Out of a total of 25 fish species cultured in China, nine species have sufficiently different
feeding habits that they can be cultured together at the same time in a single pond: grass
carp (C. idella) and wuchang fish (M. amblyocephala) feed on terrestrial plants and aquatic
macrophytes; silver carp (H. molitrix) and bighead carp (A. nobilis) feed mainly on
phytoplankton and zooplankton, respectively; black carp (Mylopharyngodon piceus) feed
on molluscs (snails); mudcarp (Cirrhinus molitrella) feed on bottom detritus; and common
carp (C. carpio) feed on benthic invertebrates and most of the above food items with the
exception of plankton (Zweig, 1985). Table 19 shows the natural feeding habits of adult
tilapias and other important fish and prawn species. Species ratios which have been found
to give satisfactory results in fertilized ponds include:
1. Common carp:tilapia (aureus): silver carp, 5:2.5:1.5; total of 4500–9500 fish/ha
(Israel - Schroeder, 1978, 1980).
2. Silver carp:bighead carp:grass carp:common carp, 65:1:4:12, with a combined
density of about 5500/ha, together with freshwater prawn (M. rosenbergii) at
density of 7.9/m2 (USA - Malecha et. al., 1981; for other prawn polyculture studies
see Wohlfarth et. al., 1985, Rouse, Naggar and Mulla, 1987, and Cohen, Ra'anan
and Barnes, 1983).
3. Silver carp:bighead carp:grass carp:wuchang fish:crucian carp(Carassius
carassius):common carp, 4500:1500:4500:3000:3000:1500/ha, total 18000 fish/ha
(China - Shan et. al., 1985).
4. Common carp (50–70%), silver carp (20–30%), bighead carp (10%), grass carp (5–
10%), and sheat fish (Silurus glanis; Hungary, ADCP, 1984).
5. Silver carp:bighead carp:grass carp:common carp, 7500:1550:4500:1500/ha, total
15000 fish/ha; silver carp:wuchang fish;crucian carp:bighead carp: grass
carp:common carp, 4500:3000:3000:1550:4500:1500/ha, total 18000 fish/ha
(China - Zhang, Zhu and Zhou, 1987; for other Chinese polyculture ratios see FAO,
1983).
6. Silver carp:bighead carp:grass carp:tilapia (niloticus, males): tilapia (aureus,
males), 2500:250:150:7500:5000/ha, total 15400 fish/ha (Alabama USA - Behrends
et. al., 1983).
1
For example, in Israel Yashouv (1971) reported a common carp production of 390kg/ha in monoculture and 714kg/ha in
polyculture with silver carp (silver carp production 1923kg/ha; both ponds receiving equal inputs of inorganic fertilizers and
poultry manure). Yashouv explains the improved growth to be the result of a “positive (synergistic) interaction on the basis of
increased food sources. Each of the fish species processes a food source; thus making it available to the other. The faecal
pellets of silver carp, which are rich in partially digested phytoplankton, make this food source available to common carp
which otherwise could not utilise the phytoplankton. The common carp, by digging and ploughing the pond bottom, release
into the water minute organic matter, which is then strained out and utilised by silver carp”.
The ultimate choice of species ratio and stocking size will depend upon the type of farming
activity envisaged (rural/subsistence or commercially oriented farming activity), the
availability and cost of fertilizers and feeds, and on the natural productivity of the water
body in question. For information on the calculation of fish polyculture ratios and stocking
densities see FAO (1983) and Horvath, Tamas and Tolg (1984).
Table 19. Natural feeding habits of some pond cultured fish and prawn species
Species
Reported adult feeding habits
1
Tilapia
- esculentus Phytoplankton
- rendalli
Macrophytes, attached periphyton
Macrophytes, benthic algae, phytoplankton, periphyton, zooplankton, fish larvae, fish
mossambicus eggs, detritus
- aureus
Phytoplankton, zooplankton
- niloticus
Phytoplankton
- kottae
Phytoplankton, detritus, invertebrates
- mariae
Phytoplankton, invertebrates
- galilaeus
Phytoplankton
- zillii
Macrophytes, benthic invertebrates
- guineensis Algae, detritus, sand, invertebrates
Algae, detritus, sand, invertebrates
melanotheron
- variabilis
Algae
- leucostictus Phytoplankton, detritus
- sparrmanii Periphyton
- shiranus
Macrophytes, algae, zooplankton
- pangani
Periphyton
-jipe
Periphyton
Milkfish (C. chanos) 2 3Algae, phytoplankton, detritus, periphyton
Grey mullet (M. cephalus) 2 3 Algae, phytoplankton, detritus, macrophytes
Prawn (M. rosenbergii) 4 Benthophagic detritivore/omnivore
1
Bowen (1982)
2
Schroeder (1980)
King and Garling (1986)
4
Malecha et. al., (1981)
3
3.2.4.2 Manure fertilization through straight manual application
The stimulatory effect of an animal manure on natural pond productivity will be determined
to a large extent by its method of distribution and application (ie. quantity and frequency of
application) to the pond. The better the distribution of the manure over the pond area the
better the fertilization effect achieved (Woynarovich, 1985; Delmendo, 1980; Edwards,
1982). Furthermore, manures which produce fine colloidal particles are more rapidly
colonised and decomposed by bacteria, and consequently will be more effective, than
manures presented in large lumps or heaps (Hepher and Pruginin, 1981). Woynarovich
(1979) found that when soft fresh animal manure was mixed with pond water and
repeatedly spread over the entire pond area that sufficient amounts of carbon compounds
were liberated to maintain a high primary productivity. This was believed to be due to the
fact that approximately 30% of the total dry matter content of the liquid cow manure
existed in a colloidal state and thus acted as an ideal substrate for bacterial and protozoan
growth on the pond bottom and within the water column (Moav et. al., 1977). Similarly,
Schroeder (1980) reported that as much as 40% of the total solids of fresh cow manure
remained in suspension in the water column; 50–60% of which being in the form of
inorganic materials. However, he also noted that approximately 90% of the coarse organic
matter settled to the pond bottom after one to two hours, and that sediment accumulations
of more than a few mm resulted in the development of anaerobic sediment conditions. It
follows from the above that there is a maximum amount of manure that a pond can
aerobically digest/unit area/unit time; the addition of manure above this maximum level
leading to the accumulation of organic matter on the pond bottom and the development of
undesirable anaerobic interstitial conditions (Edwards, 1982). According to Schroeder
(1980) the maximum amount of manure that a pond can safely digest without undesirable
anaerobic effects is about 100–200kg manure dry weight/ha/day or 70–140kg organic
matter/ha/day (for Israeli pond conditions). These values correspond approximately to the
manure produced from 100–200 pigs weighing 100kg each/ha/day, 15–30 cows weighing
500kg each/ha/day, or 2000–4000 poultry each weighing 2kg each/ha/day (Edwards,
1982). To obviate the possible dangers of water deoxygenation within manure loaded and
eutrophic ponds (due to unchecked peaks in bacterial growth and phytoplankton blooms),
manures should be added as frequently as possible, at least daily, on a little and often
basis (Hepher and Pruginin, 1981; Wohlfarth and Schroeder, 1979; Schroeder, 1978;
Woynarovich, 1979). Although the oxygen demand of the manure itself is not great if the
manure is evenly distributed over the pond surface, it is recommended to apply manure to
a pond during mid-morning when oxygen levels are rising rapidly due to photosynthesis;
this in turn would minimise the oxygen demand caused by the bacterial breakdown of the
manure itself during the critical pre-dawn hours (Woynarovich, 1980; Edwards, 1982). In
addition, since the manure requirement of a pond will depend upon the dietary live food
requirements of the fish/shrimp biomass present, it follows that the manuring rate will have
to be increased (up to a maximum safe level) with increasing fish biomass or standing crop
(Hepher and Pruginin, 1981). Figure 16 shows the relationship between total standing crop
and daily manure requirement obtained by Wohlfarth (1978) for Israeli fish ponds.
Examples of manure fertilization programmes which have been employed by other
workers are shown in Table 20. It must be remembered, however, that the manuring rates
shown are pond and farm specific, and as such should only be used as tentative
‘guidelines’ by persons wishing to develop their own pond fertilization programmes.
Figure 16. Relationship between manure requirement and standing crop in Israeli fish
ponds (Wohlfarth, 1978)
Three basic methods are currently employed for the distribution of animal manure to fish or
shrimp ponds (Woynarovich, 1979):



The dilution of the manure on land and the distribution carried out by hand from the
shore or from a small boat. This method is normally used for small ponds (Figure
17, A1–3).
Soft manure is shovelled into a basket of parallel iron rods (approx. 2–2.5cm
apart), suspended 10–20cm below the water line, attached to the side of a boat,
and dispersed as the boat moves and forces water into the basket (Figure 17, B1).
The use of a pump built into the bottom of a boat; the manure is shovelled into a
hopper, diluted with pumped water and sprayed out into the pond through a flexible
hose (Figure 17, C1).
Figure 17. Organic manure distribution methods (Woynarovich, 1985)
Table 20. Examples of manure fertilization programmes for pond fish and shrimp
FRESHWATER
1. General fish - Israel (Schroeder, 1980):
- Manuring rate computed as dry organic matter at 2–4% of the standing fish biomass daily.
Calculation is based on the dry organic matter content of the manure, and so excludes ash. The
manure should be distributed in liquid or moist form, retaining the urine and faeces. At this
manuring rate, with a polyculture of 9000 fish/ha, the fish yields are 20–30kg/ha/day (in
conjunction with standard inorganic fertilization rates - Table 15).
2. General fish - Panama (MIDA, 1985a):
Recommended
manuring
dried pig manure - 68kg/ha/day
rates:
dried poultry manure - 50kg/ha/day
dried cattle manure - 100kg/ha/day
3.
-
4.
-
5.
6.
-
7.
-
8.
9.
-
-
-
10.
-
dried goat manure - 100kg/ha/day
To ensure a good production of pond food organisms, the authors recommend the single
application of one months manure supply to the pond two weeks prior to stocking.
General fish - Brazil (Woynarovich, 1985):
Recommended manuring rates: Fresh poultry manure - 500kg/ha/1–2 days or 1000kg/ha/1–2
weeks Fresh pig manure - 700kg/ha/1–2 days or 1400kg/ha/1–2 weeks Fresh cattle manure 1000kg/ha/1–2 days or 2000kg/ha/1–2 weeks
Carp/tilapia polyculture - USA (Behrends et. al., 1983):
Liquid pig manure added daily to the pond at a mean dry matter loading rate of 61kg/ha/day
with a combined stocking rate of 15,400 fish/ha (for species ratio see polyculture section of this
report, 3.2.4.1). Average total solids content of liquid manure was 0.4%, and supplied an
average of 5.5kg nitrogen, 4.3kg phosphorus (as P2O5) and 33kg carbon/ha/day. Liquid pig
manure was composed of a mixture of faeces, urine and wasted feed.
Carp polyculture - China (Shan et. al., 1985):
Liquid pig manure added to the pond at a nominal daily rate of 2% (dry weight basis) of the fish
biomass (18,000 fish/ha; for species ratio see polyculture section of this report, 3.2.4.1).
Tilapia hybrid (hornorum males X mossambica females) - Costa Rica (Gonzalez et. al. 1987):
Dried poultry manure added daily to the pond at a rate of 110kg/ha/day; 15 days prior to
stocking (1.5 fish/m 2) the limed pond bottom was treated with 1200kg dried poultry manure. The
poultry manure used had a moisture content of 9–14% and a ash content of 25–28%. A
manure:fish conversion efficiency of 7.9 was obtained over the 255 day culture cycle
(conversion efficiency includes manure used for pond preparation and daily application rates)
with a extrapolated total fish production of 4926kg/ha/year (4363kg/ha/year - net production).
Manure application rates of 55–175kg/ha/day were also tested.
Tilapia - Rwanda (Schmidt and Vincke, 1981):
Recommended manuring rates:
General animal manure:
300–500kg/ha/2weeks (T. nilotica spawning ponds)
500kg/ha/2weeks (T. nilotica fingerlings, 5/m 2)
Cow manure: 300kg/ha/week; Horse manure: 2000–3000kg/ha/month; Poultry manure: initial
application of 2500kg/ha, followed by monthly application of 1000kg/ha (T. nilotica fingerlings,
2/m2).
Red drum - USA (Colura, 1987):
Manuring nursery ponds with cottonseed meal (for application rates see Table 15).
Carp polyculture - Hungary (Olah et. al., 1986):
Liquid pig manure with a mean dry weight of 10% applied daily using a rotary sprinkler at a rate
of 2m3/ha/day. Polyculture employed consisted of silver carp (3500/ha, mean weight 190g) and
common carp (1800/ha, mean weight 150g).
Sedimented raw domestic sewage applied daily using a rotary sprinkler at a rate of
100m3/ha/day. Polyculture employed consisted of silver carp (1500/ha, mean weight 190g),
bighead carp (800/ha, mean weight 180g), common carp (1400/ha, mean weight 200g) and
grass carp (300/ha, mean weight 170g).
Woynarovich (1980) reviews the use of pig manure for fish production, and describes manuring
rates (by daily water dispersion) of 300–600kg/ ha/day for pig manure, 1000–1500kg/ha/day for
the thick liquid phase of the manure, and 1.2–2.5m3/ha/day for commercial piggery sewage in
Hungarian polyculture fish ponds.
Tilapia nilotica - Thailand (Edwards et. al., 1984):
Liquid Bangkok cesspool slury applied daily at an organic loading rate of 150kg COD (Chemical
Oxygen Demand)/ha/day; stocking density of 1fish/m 2. The total solids (TS) and total volatile
solids (TVS) content of the cesspool slury used varied between 13.75–29.42g/1 (mean 20g/1)
and 9.49– 22.67g/1 (mean 13.9g/1). The mean COD of the cesspool slury used was 28.7g/1;
ponds receiving an equivalent dry matter loading rate of 75.7– 124.5kg/ha/day.
- For further information on the use of human waste waters in aquaculture see Edwards (1984)
and Johnson Cointreau (1987).
11. Tilapia/freshwater prawn polyculture - USA (Teichert-Coddington et. al., 1987):
- Liquid pig manure applied daily at a rate of 17 or 51kg/ha/day (dry matter basis). Highest prawn
production observed with the lowest manuring rate tested. Polyculture consisted of 3 prawn post
larvae/m2 with T. nilotica and T. aurea fingerlings at 0.8/m 2.
12. Tilapia/freshwater prawn polyculture - USA (Rouse, Naggar and Mulla, 1987):
- Ponds fertilized prior to stocking with dry chicken manure at a rate of 1000kg/ha, followed by
weekly applications at 200kg/ha. Polyculture consisted of a freshwater prawn density of 3.5–4
post-larvae/m2 and a tilapia (fry or fingerling) density of 0.5–1.5/m2 (T. nilotica/T. aurea).
BRACKISHWATER/MARINE (see also Table 15 for ‘lab lab’ production)
13. Shrimp (P. vannamei) - USA (Wyban et. al., 1987):
- Ponds fertilized with feedlot cattle manure at a rate of 1800kg/ha/week (shrimp density 5–
10/m2). Moisture content of manure not given. However, since the application rate used was
based on the results of the study of Lee and Shleser (1984), it is assumed that the manure
application rate employed refers to the use of sun-dried manure.
14. Shrimp (P. stylirostris/P. vannamei) - Panama (Garson, Pretto and Rouse, 1986):
- Ponds fertilized with 910kg/ha (dry weight) of chicken manure or cow manure 60 days prior to
stocking, and thereafter applied every 2 weeks at a rate of 450kg/ha. Stocking density
employed was 5 shrimp/m 2. Average shrimp yield (tails only) over a 120-day production cycle
where reported as 262kg/ha (chicken manure) and 218kg/ha (cattle manure).