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FacultyOf FisherySciences
SRP-425
Experimental learning programe
West Bengal University Of Animal And Fishery
Sciences

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A seminar on :-
soil & water quality managements
for sustainable aquaculture
Submit to : Submit by: Prof. T. K. Ghosh &
Sukalpa Mandal Dr. S. k. Sau roll no= f/2017/32
Dept. Of AQC reg no= 6159of 2017-18
Srp- 425 (aqua-farming)

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Topics Name Slide No.
Aquaculture Vs. Sustainable Aquaculture 4
Water Quality Management
1. Introduction
2. Temperature
3. Turbidity
4. Salinity
5. Alkalinity
6. pH
7. Hardness
8. DO
9. CO2
10. Ammonia
11. Nitrite
12. Nitrate
13. Hydrogen Sulphide
14. Biological Characteristics
5-7
8-9
10-13
14-16
17-19
20-21
22-24
25-29
30-32
32-33
34-35
36
37-38
39-42
Soil Quality Management
1. Introduction
2. Management practices
3. Parameter Suitability
4. Sustainable pond productivity
43-44
45-47
48
49
Conclusion 50
Reference 51

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• what is aquaculture?
Aquaculture has been defined in many ways. It has been called as the rearing of aquatic
organisms under controlled or semi controlled condition - thus it is underwater agriculture.
Another one is simply the large-scale husbandry or rearing of aquatic organisms for
commercial purposes.
• What Is Sustainable Aquaculture ?
Sustainable aquaculture is the cultivation of aquatic organism for commercial purposes by
means that have a good natured impact on the environment, contribute to local social community
development and to generate an economic profit.
It is a dynamic concept and the sustainability of an aquaculture system will vary with
species, location, societal norms and the state of knowledge and technology.

Introduction
◦ The success of aquaculture can be assured by selecting a suitable site with good
quality soil and water. It is essential to understand the pond soil and water
characteristics and their optimum requirements to increase the productivity off the
ponds.
◦ Succesfull pond culture operations mainly depends on maintenance of a healthy
aquatic environment and production of sufficient fish food organisms in the pond.
◦ A healthy water is boon to fish culture.

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• Selection of source water = Decide the efficient production
• Freshwater aquaculture= Ground water sources(springs & Wells)=Maintain a
constant temperature and free of biological nuisances = less contaminated than surface
water sources.
• Salt or brakish water aquaculture = source water should be away from ant
generator of pollution, such as industries,tainted rivers mouths, or agricultural areas
• Fish and Shellfish Health = Very sensitive to water quality

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• Physical Factors
1. Temperature
2. Turbidity
3. Light
• Chemical Factors
1. Salinity
2. Alkalinity
3. pH
4. Hardness
5. DO
6. Carbon dioxide
7. Ammonia
8. Nitrite & Nitrate
9. Hydrogen sulphide

Temperature
•Water temperature affects a multitude of important processes such as
∆ Physiological processes in fish such as respiration rates, feeding, metabolism,
growth, behaviour, reproduction etc
∆ Rates of detoxification and bioaccumulation
∆ Disolved oxygen level in water such as the solubility of oxygen
∆ Rate of oxidation of organic matter
∆ Solubility offertilizers can be affected by temperature
• Site selection = Ambient temperature
• Species selection = According to available water temperature

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Turbidity
◦ Measure of light penetration in water.
◦ Turbid condition = Dissolved and suspended solids (clay particles,humic substances,
plankton, coloured compounds etc.
◦ Pond turbidity
∆ Sediment resuspension
∆ Biological activity
∆ Addition of manure and feed
∆ Erosion of the pond slopes

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• Turbid waters
1. Gill damage and fish stress
2. Clof filters
• Affect the lights
1. Oxygen levels reduced due to photo- synthesis inhibition.
2. Phytoplankton dependent feeder may affected
• Turbidity = Avoid the growth of undesirable rooted plants.
• Channel catfishes are more tolerant with their fingerlings and adults surviving long –
term exposures to 100,000 mg/l with behavioural changes occuring above
20,000mg/l.
• Salmonid culture = <30 mg/l , <80 mg/l and < 25 mg/l

Secchi Disk

Treatment
• Colloids or very small suspended particles = Electrolytes such as alum .
• While alum is very effective but, reduce the alkalinity and pH. Lime can be added to
counteract these effects.
• Suspended clay = Organics such as barnyard manure, cottonseed meal or
superphosphate.

Salinity
• Salinity is a measure of the total concentration of dissolved ions (ppt).
• Freshwater = High concentration of carbonate, silicic acid, calcium, magnesium and
sodium .
• Salinity of sea water varies = Proximity tobyhe coastline , rainfall, rivers and other
discharges.
• Chloride and sodium ions contribute most significantly with sulfate , magnesium ,calcium
potassium and bi carbonate ions contributing to lesser degree.
• Salinity is immensely important to fish which must maintain the concentration of dissolved
salts in their bodies at a fairly constant level through the process of osmoregulation
(homeostasis).
• Euryhaline species (Asian sea bass) can be cultured in a broad range of salinity from
fresh to seawater but stenohaline fish (Cobia) can be cultured only in full strength
seawater.

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Species Salinity (PPT) Comments
•Salmon >24 Optimum
•Trout <20> Survival and growth decrease
above 20%
•Grass carp <10-14 Upper Salinity tolerance
•Tilapia and Tilapia nilotica 0-10 Optimum
•Red hybrid tilapia <17
•Channel catfish • 11-14
• >6-8
• 0.5-3.0
• <0.5
• <3
• 0.1-8.0%
• Can survive
• Growth is poor
• Optimal
• Can still grow well
• Optimal for egg
• Optimal for hatcheries

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Species Salinity (PPT) Comments
•Freshwater prawn 12% Optimum
•M.rosenbergii <0.5% Post-larval stages
•Brakish water prawn • 15-25%
• 10-35%
• Optimum
• Acceptable range
•P. vannamei 15-25% Optimum
•Marine fish • 33-35%
• 30-40%
• Optimum
• Acceptable range
Refractometer

Alkalinity
• Alkalinity is a measure of the acid neutralizing capacity of a water.
• Alkalinity in natural freshwater systems ranges from 5mg/l to 50 mg/l . Sea water has a
mean total alkalinity of 116 mg/l.
• The principal ions contribute to alkalinity are carbonate and bicarbonate and, to a lesser
degree, hydroxides, ammonium, borate, silicates and phosphates.
• There are no direct effects of alkalinity on fish and Shellfish.
• Alkalinity protects the organisms from major changes in pH.
• The metabolism and respiration of fish and micro – organisms = produce wastes and by
products which can change pH.
• Biological processes can change alkalinity itself by producing or consuming acids or bases.
• Alkalinity is too low (less than 20 mg/l) the water may not contain sufficient carbon dioxide
or dissolved carbonates for photosynthesis to occur , thus restricting phytoplankton growth.

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Total Alkalinity Effect Reference
1. 15-20 Phytoplankton production low Boyd(1974)
2. <30 Poorly buffered against rapid
pH changes
Meade(1989)
Tucker and Robinson (1990)
3. 20-400 Sufficient for most aquaculture
purposes
Meade(1989)
4. >100/150 Desirable Meade(1989)
Tucker& Robinson(1990)

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pH
• The pH of water is it’s hydrogen ion concentration ([H+])= -log[H+]
• Natural waters range between pH 5 and pH 10 while seawater is maintained near
pH8.3 .
• For most species, a pH between 6.5 and 9is ideal. Below pH 6.5 species experience
slow growth.
• Lower pH
◦ Species ability bto maintain it’s salt balance is affected.
◦ Reproduction ceases.
◦ Species die when pH<4 and > 11
◦ Reduces the amount of dissolved inorganic phosphorus and carbon dioxide available for phytoplankton
photosynthesis.
◦ Metal toxic to fish and shellfish can be reached out of the soil .
◦ Treated by using lime.

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• High pH
◦ Toxic from of ammonia becomes more prevalent.
◦ In addition phosphates,which is commonly added as a fertilizer,can rapidly precipitate at high pH.
◦ Alum can be used to treat high pH waters .
◦ High pH problem is due to excess phytoplankton photosynthesis in waters with high alkalinity and low
calcium hardness, gypsum can be added as a source of calcium.
pHmeasurement

Hardness
• Total hardness is a measure of the convey of all metal cations with the exception
bofbthe alkali metals.
• Calcium and magnesium are the most common cations contributing to hardness
in fresh water systems.
• To a much lesser extent , hardness also includes other divalent ions such a iron
(Fe2+)
and barium (Ba2+).
• Water is classified with respect to its hardness and softness.
Water classification Concentration (CaCo3/lt)
1. Soft 0-75mg
2. Moderate 75-300mg
3. Hard 150-300mg
4. Very Hard >300mg

Calcium
• Necessary for bone and exoskeleton formation and for osmoregulation.
• Crustaceans absorb calcium = when molting
• The water is too soft
1. Cease to molt
2. Bone deformities
3. Reduced growth rate
• Calcium reduced the toxicity bof metals, ammonia and the hydrogen ion.
• Higher ion concentration in hard waters
◦ Suspended soil particles settle faster in hard waters than soft waters.
• Alkalinity is high and calcium is low =Photosynthesis may increase the pH to levels that are toxic to fish.

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• The most productive waters for fish culture have roughly equal magnitudes of Total
hardness and total Alkalinity.
• Hardness averages 6,600 mg/l in ocean water and therefore is not a problem in
seawater or brakish water systems.
• Insufficient hardness is easily overcome.
1. Calcium hardness can be raised by adding agricultural gypsum or
calcium chloride.
2. Gypsum is preferable because it costs less,is more readly available ,
and does not affect alkalinity.
• It’s disadvantages= Variable purity of agricultural gypsum (70-98%) and it’s slow
reaction rate relative to calcium chloride.

Dissolved Oxygen
• Sources of dissolved Oxygen are photosynthesis and reaeration from the atmosphere.
• Oxygen – consuming process such as respiration from microbial life, fish and plants
and the degradation of organic matter by microorganisms (BOD).
• Influenced by temperature.
• The type of fish, life stage, feeding practices, level of activity and dissolved oxygen
concentration also influence the respiration rate.

Biological Oxygen Demand
◦ Measure of the amount of organic compounds that can be biological oxidized by
microorganism in water.
◦ BOD is the potential for it to deplete oxygen
1. Higher BOD promotes the microbial growth at higher temperatures. This can lead to the depletion of O2.
◦ Treatment are potassium permanganate and aeration
1. Potassium permanganate chemically oxidized organic matter, thus reducing BOD. But not suitable for production
system.
2. Most effective method = Aeration

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Oxygen is most important environmental parameter that exerts a tremendous effect on
growth and production through its direct effect on feed consumption and metabolism
and its indirect effect on environmental conditions. Oxygen affects the solubility and
availability of many nutrients. Low levels of dissolved oxygen can cause changes in
oxidation state of substances from the oxidized to the reduced form. Lack of dissolved
oxygen can be directly harmful to culture organisms or cause a substantial increase in
the level of toxic metabolites. It is sherefore important to continuously maintain
dissolved oxygen at optimum levels of above 3.5 ppm.

Marine water fresh water

Carbon Dioxide
• Sources = Diffusion from the atmosphere , fish respiration and the biological oxidation
of organic compounds.
• Surface water sources can have high levels of Carbon dioxide= Respiration high rates.
•CO2 concentration are too high= Fish blood CO2 incresed
◦ Impairing the ability of their hemoglobin to carry oxygen.
◦ Respiratory distress (Bohr – Root effect)
Aquaculture type Free Co2(mg/lt) Comments
1. Hatchery 0 Ideal
2. Trout <10
3. Warm water <15
4. Channel catfish <10 Ideal
5. Finfish <10-15 Maximum

Treatment
• Either calcium hydroxide, also known as salke or hydrated lyme, or sodium carbonate may be
added to reduce high levels of Carbon dioxide. However, calcium hydroxide is cheaper band
more widely available.
• Sodium carbonate is safer because, unlike calcium hydroxide, it is not caustic and will not
cause a substantial rise in pH.
• Vigorous mixing and aeration is also a good method for removing excess carbon dioxide.

Ammonia
• Initial product of the decomposition of the nitrogenous organic wastes and respiration
amd may indicate the presence of decomposing urea, feces and organics.
• High concentration of ammonia= Increase the pH is fish blood.
1. Gill damage
2. Reduce the oxygen carrying capacity of blood
3. Increase the oxygen demand of tissues
4. Damage red blood cells
5. Affect osmoregulation
• The toxicity of Total ammonia nitrogen (Tan which is equal to NH4+ & NH3) depends
on what fraction of the total is unionized , since this is more toxic from.
• Ionized and unionized ammonia-equilibrium – depending on pH, temperature, and
salinity.

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• Ammonia toxicity can be influenced by temperature and salinity.
• In general warm water fish are more tolerant to ammonia than cold water fish, and freshwater
fish are more tolerant to ammonia than marine fish.
• In brakish water shrimp farms , zeolites are known to be added to control ammonia
concentrations.
• Zeolites have been shown to be technically effective in freshwater .
• Other options include using aeration to oxidize the ammonia to nitrate (nitrification)or to adjust
the ammonia to nitrate (nitrification) or to adjust the pH and usebair stripping to volatilize the
ammonia.

Nitrite
• Nitrite is formed primarily as an intermediary in the conversion of ammonia to nitrate, a
process known as nitrification.
• High Nitrite concentration deactivate hemoglobin in the blood of fish thus causing
hypoxia. This condition is referred to as brown blood disease. A similar effect is found in
crustaceans.
•Nitrite toxicity reduced by ions such as calcium, chloride, bromide and bicarbonate. As
a result ,it is rarely a problem in saltwater and brakish water.
• Treatment = Aeration can be used to promote the nitrification process.

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Species or Water Conc. Comment
Hard water <0.1
Soft water <0.1
Fresh water fish <0.5 Hatcheries
Brakishwater Fish <4.1
P.monodon <4.1 Post-larval growout
P. Vananmei <1.0 Optimum
Salmonid • <0.01
• <0.1
• Soft water
• Hard water

Nitrate
• Nitrate is the least toxic of the major inorganic nitrogen compounds.
• High levels of nitrate can affect osmoy and oxygen transport
High nitrate levels
Eutrophication, excessive growth
of algae and aquatic plants-
negative impact on culture
species.
Species Conc(mg/l) Comment
Carp <80 Optimum
Trout <20 Optimum
Freshwater
hatchery
<3 Optimum
P. Vannamei 0.4-0.8 Optimum
General • <3
• <100
Permissible

Hydrogen Sulphide
• Hydrogen sulphide (H2S) is produced by bacteria under oxygen starved
(anoxic) condition.
• It is very toxic to fish.
• Even extremely low concentration of hydrogen sulphide cause hypoxia and are
deadly or extremely harmful to fish.
• Concentration as little as 0.05 mg/l have caused death after only a brief
exposure and concentration less than 0.01 mg/l have inhibited reproduction.

Treatment
• Oxidation with potassium permanganate or dilution through water exchange are the
best method of hydrogen sulfide removal.
• Prevented by vigorous aeration and circulation to eliminate banaerobic zones.
• As a method of hydrogen sulfide removal , some companies in Asia are selling
photosynthetic bacterial additives which claim to convert hydrogen sulphide to sulfate.

Biological Characteristics
Phytoplankton, Diatom, Dinoflagellates
Zooplankton
Benthos
Water plant
Water insect
Protozoa
Bacteria
Fungi

Nutrient Cycle
• Bacteria from the bas eof the food chain within an aquaculture pond.
• Bacteria break down organic matter to produce nutrients such as Phosphorus,
Nitrogen & Carbon etc.
• These products are then utilized by phytoplankton, microscopic algea to produce
oxygen via photosynthesis.
• Oxygen and phytoplankton are then consumed by zooplankton, the tiny aquatic
organisms.
• Fish feed on zooplankton asa well as larger aquatic plant and supplementary feed that
may be added to the aquaculture pond.
• Uneaten supplementary feed, dead aquatic organisms (including planktonic organisms
and aquaculture species) and animal wastes on the pond floor.
• Bacteria will feed on this decaying organic matter and the cycle will commence again.

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Successsion
• An aquatic organisms within an aquaculture system will vary over the time.
• It is therefore important to have a good understanding of the population dynamics within your
pond to stabilize population number of aquactic organisms and to ensure that system will not
crash.

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Water Quality Suitability

Soil Quality Management
Introduction:-
Aquaculture ponds are normally built on soils. Selection of potential and suitable sites is the
first and foremost step for successful aquaculture. The success of fish culture depends on
Essential features namely good bottom soil and better quality of water. Aquaculture ponds are
normally built of soils. Properties of soils should be considered in selecting a site, designing
earthwork, and specifying construction methods to provide a water-tight pond with stable
levels and bottom slopes. The nature of a particular soil type is dependent on its physical
properties and nutrient content. Soil quality is an important factor in pond productivity as it
controls pond bottom stability, pH and salinity. It also regulates the quality of the overlying
water.

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• Bottom soil is considered as the chemical laboratory of the pond. However, suitable soil
quality problem are common in aquaculture, and therefore, many methods are used for
purpose of improving pond soils.
Soil Texture : The nature and the properties of the parent material forming the soil
determine the soil texture. An ideal pond soil should not be too sandy to allow leaching of
the nutrients or should not be too clayey to keep all the nutrients absorbed on to it. For
sandy soil, heavy dose of raw or composed farmyard manure varies from 10000 to 15000
kg/ha/year is required.

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Problem Preventive measure
Low soil pH • Neutralize acidity of new pond bottom soil
before initiating aquaculture.
• Use urea and ammonium fertilizers
conservatively.
• Monitor total alkalinity of pond water and soil
pH to assure that total alkalinity is above
75mg/lit and soil pH is above 7 in water body.
High soil organic matter • When bottom soil are organic , apply
agricultural limestone and urea (200 to 400
kg/ha) to encourage degradation of organic
matter during follow periods.
• Use moderate stocking rates to avoid high
inputs of nutrients and organic matters in
fertilizers, manure and feeds.
Continue…….
Management practices for pond bottom – soil quality

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Problem Preventive Measure
High soil organic matter • Dry ponds between crops ,apply agricultural
limestone according bto soil pH, and till heavy
textured soils to encourage oxidation of organic
matter by bacteria.
• In areas where pond bottom soils cannot be
dried , apply nitrate fertilizers.
• Monitor soil organic matter concentration
annualy.
Loss of oxidize layer • Follow preventive measure for avoiding
accumulation of organic matter on bottom.
• Where a surface layer high in organic matter has
developed in bottom soils, use turning plough to
expose higher quality soil.
• Monitor appearance of soil. The upper few
milliliters should be of natural natural soil color or
brownish. A grey or black colour nat surface
indicates reduced (anaerobic) condition.
• Maintain adequate plankton to restrict light and
prevent mats of benthic algae.

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Problem Preventive Measure
Excessive accumulation of soft sediment • Remove soft sediments from water body.
• Use proper side slopes and compaction when
constructing new ponds or renovations old ones.
• In ponds with mechanical aeration, install
aerators to prevent water currents from eroding
insides of embankments.
• If sites of active erosion are observed,
measures for lessening erosion should be
installed. These measures may include
installation of rip-rap , proper sloping and
compaction, grass cover etc.
• Do not leave ponds empty longer than
necessary during rainy season to prevent erosion
from shallow area to deeper area.
• Monitor pond bottoms periodically, avoid
operating equipment that will cause ruts and
other inundation in pond bottom.

Soil Parameter Suitability

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Sustainable PondProductivity
Nutrient removal : It is possible to precipitate phosphorus from pond water by applying sources of iron,
aluminium or calcium ions. Alum (aluminium sulphate) or ferric chloride are commercially available of which
the former is cheap and widely used. Alum @ 20-30 ppm is more suitable in alkaline water (>500 ppm) and
gypsum (calcium sulphate) @ 100-200 ppm is better in low alkaline water.
Plankton removal : Copper sulpahte @ 1/100 of the total alkalinity is recommended for reducing
phytoplankton abundance and blue-green algae in particular.
Chlorination : It is possible to disinfect bottom of empty pond and waters in newly filled and unstocked
ponds by applying chlorine products @ 1ppm or more of free chlorine residual. The residuals will detoxify
naturally in a few days so that ponds can be stock safely.
Liming : Liming should be always done depending upon the pH of the water and the soil. As the health of
the soil determines the nature of the pond water, pH of the water can be taken as reference to determine
appropriate dose of application

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1. Good bottom soil and water quality are vital ingredient for any successful
aquaculture practices.
2. Although such problems are related to site characteristics bottom soils have
undesirable properties viz acid sulphate, high organic and excessive porosity
etc.
3. Similarly, the water may have poor quality, viz highly acidic, rich in nutrient
and organic matter, high in suspended solids or polluted with industrial or
agricultural chemicals.
4. Maintaining a good pond environment through use of proper management
practices will reduce the stress, risk of disease, increase production, improve
productivity and livelihood.
Conclusion

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• Ecourse.icar.in / Handbook of ICAR
• Lawson, T. B. 1995. Fundamentals of Aquacultural Engineering. New York:
Chapman and Hall.
• Lloyd, R. 1992. Pollution and Freshwater Fish. West Byfleet: Fishing News Books.
• Bureau of Agricultural Statistics. 2006. Fishery Production in 2006.
http://countrystat.bas.gov.ph/PX/Dialog/Saveshow.asp
• Boyd, Claude E. 1990. Water Quality in Ponds for Aquaculture.
• FAO.Org.In /Committee on Water quality. Technical Report Series no. 776. Geneva.
References

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