Water Chemistry Monitoring . Spectrophotometers & Reactives & Multi Parameters
WATER QUALITY MANAGEMENT IN SHRIMP AQUACULTURE
Water is a finite source.
Universal Solvent.
Only 3 % of water is Fresh water, 97 % saline.
Quality of water is more important than Quantity.
Shrimp is very sensitive to water quality and poor water quality effects Shrimp.
Water quality determines the success or failure of shrimp culture.
Maintenance of good water quality is essential for both survival and optimum growth of shrimp.
Water treatment is an important step for the maintenance of good water quality at later stage.
Water Quality Management-Pre-Stocking
After harvest of a crop, the deposits of organic debris in the pond bottom should be removed, or
treated, ploughed, tilled and levelled.
Three Stage water filtration with different mesh size shall be done before stocking it into reservoir
pond.
Chlorinate water in the reservoir with sufficient chlorine (10ppm) to kill any potential vectors or
carriers in the source water.
Water Quality Management-General Precautions
The pH should be in optimum level of 7.5 to 8.5 and should not vary more than 0.5 in a day.
Variations in salinity not exceeding 5 ppt in a day will help in reducing stress on the shrimp.
The optimum range of transparency measured using secchi-disc is 25-35 cm.
Total Ammonia Nitrogen ( TAN ) and nitrite N concentration should not be more than 1 and 0.5 ppm, respectively. Any detectable concentration of hydrogen sulphide is considered undesirable.
The use of aerators results in mixing of water at surface and bottom and break downs the DO and thermal stratification.
Water Quality Management-Physical Parametres
Very important in regulating the activities of cultured animal.
D.O. requirement will be higher in warmer waters than cold waters.
Low and high temperature leads to low and high metabolicrate, respectively.
Higher temperatures more weakens the physiological conditions of animal like low feed intake,
stress etc… and sometimes leads to mortality.
Higher temperature increases salinity, evaporation of pond water and increases mineral
composition.
Optimum temperature 25-30 oC for Penauesspecies, 28-32 oC for vannamei.
Increase of temperature can be managed by water topping and better aeration.
Turbidity is the measure of light penetration.
Turbidity is due to dissolved & suspended solids- clay- microorganisms, phytoplankton etc.
The tubidity in pond during culture– erosion of pond slopes, sediments, plankton.
Low turbidity indicates poor productivity whereas high turbidity causes several problems like
photosynthesis inhibition, reduction of Oxygen and gill damage. It can be treated by alum application
photosynthesis inhibition, reduction of Oxygen and gill damage. It can be treated by alum application
in pond water.
Turbidity due to plankton is good to certain extent for shrimp. But turbidity due to suspended silt
particles is harmful and undesirable for healthy pond.
Proper drying of pond bottom after the harvest, strengthening of dykes, recommended arearation
reduces soil particles thereby reduces turbidity.
Salinity as a single factor plays an important role in shrimp farming as it is responsible for many
functions such as metabolism, growth, osmotic behaviour, reproduction etc.
If the salinity is allowed to go beyond the optimal limit, the shrimp refrain from taking normal food and
hence are emaciated and becomes us ceptible to disease.
The pH indicates acidic or basic nature of water. It is an index of the presence of metabolites,
photosynthetic activity and the fertility of the solid water. Low pH is reported to be harmful to
crustaceans and higher pH can lead the alkaline death.
Fluctuations in pH are result of interplay of photosynthesis ans respiration.
During day time, phytoplankton absorb CO2 for photosynthesis, causing pH to rise.
At night respiration increases, creating carbonic acid and causing pH to fall.
Large pH daily changes can stress the animal.
Lower pH can be treated with lime application where as higher pH can be treated by the application
of alum or gypsum. ( If high alkalinity and low calciumhardness. )
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pH should not vary more than 0.5 in a day.
High pH value means water is too fertile, therefore, there is the possibility of plankton bloom, which
remove carbon dioxide for use in photosynthesis and more oxygen is formed.
High pH can dramatically reduce the ammonia ionisation constant increasing % of the toxic
unionized portion.
To reduce pH, carry out water exchange / apply jaggery solution or fermented juices.
DO is required for higher rate of organic matter decomposition by aerobic microorganisms,
supports ammonia oxidation by denitrifying bacteria, maintain aerobic conditions at the sediment
water interface and better feed utilisation.
If oxygen is short, the ability of shrimp to metabolize feed will be limited causing slow growth rate.
FCRs are obtained best when DO is maintained at or above 80 % of the saturation level.
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Alkalinity is the concentration of carbonates, bicarbonates and hydroxyl ions.
It is the measure of the acid neutralizing capacity of water or the bufferring capacity of water to
resist change in pH. Measures in mg/lit
Alkalinity is important for pH optimization and plankton development, metabolic activity of shrimp
and affects bottom metabolities.
If alkalinity is too low, water may not contain CO2 or dissolved carbonates to occur
photosynthesis. Prefer dolomite to increase alkalinity. Water pH and enhances the availability of
nutrients.
Hardness is the sum of polyvalent cation concentrations dissolved in water mostly Ca++ and Mg++ .
Mineral supplements can be given if hardness is less.
Hard waters have the capability of buffering the effects of heavy metals such as copper or zinc.
Hardness is a vital factor in maintaining good pond equilibrium.
Both Hardness and alkalinity can be increased by adding either CaCO3 (Agri Lime) or CaMg (CO3)2 ( Dolomite Limestone ).
Dolomite promotes plankton growth and helps in photosynthesis of planktons.
Ammonia is present in two forms, un-ionized ammonia ( NH3 ) and ionized ammonia ( NH4+ ). The toxic form is unionised NH3. The total of both the ionised and unionised forms is total ammonia nitrogen ( TAN ). Shrimp utilizes only ionic forms for their metabolic activity. The uneaten feed and faecal matter are the sources of ammonia generation at the shrimp pond bottom.
Subsequently, ammonia is the initial product of the decomposition of nitrogenous organic. Subsequently, ammonia is the initial product of the decomposition of nitrogenous organic wastes which indicate the presence of toxic gas in the water. Usually, the equilibrium of ionized and un-ionized ammonia depends on pH, temperature and salinity. Hence, water exchange should be done to avoid this problem. In addition that, zeolite shall be applied to mitigate the toxic gases.
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Nitrite and Nitrate during the nitrification process, the ammonia is converted into nitrite by Nitrozomonas sp and nitrite is further converted into nitrate by Nitrobactor sp. In which, nitrite is more toxic to culture species when compared to nitrate. Hence, nitrite level shall be mitigated as like ammonia. Generally high nitrite are uncommon. It is found in intensive cultures. High Nitrate will effect osmoregulation and oxygen transport.
Water Quality Management-Biological Parametres
Biological Parametres – Plankton and Micro Organisms :
Plankton : Plankton abundance is higher in summer and diverse in winter crops.
Phytoplankton absorb nutrients from water for use in growth, and remove ammonia nitrogen from
water, which is particularly important in lessening concentrations of this potentially toxic metabolite
(Boyd). Over abundant phytoplankton in aerated ponds can cause unacceptably large in creases in
pH and associated increases in NH3 concentration. ( Boyd )
Bacteria, Fungi and Virus. Inwhich, pathogenic organisms cause disease to culture species.
Hence, the proper biosecurity should be maintained through out the culture.
Additionally, water and soil probiotics should be applied to eliminate the pathogenic bacteria from
the system.
Water Chemistry Monitoring . Spectrophotometers & Reactives & Multi Parameters
Magic Shell
Shrimp VIT Mix – Multivitamin and amino acid support for prawns
Vitamin C
Magic D plus Enzyme -Vegetable Enzyme breaks down Organic Solids to eliminate Sludge, Waste, Odors
Fork Dee for Aqua – Aqua Dee – Vitamin D3 Supplement – Liquid
3-Pro for Aqua – Probiotic Promoter Supplement
Nax Dine 99 for Aqua -Iodine Complex 90% – Antibacterial, Anti-Virus, Anti-Fungal Powerful Protozoa
D-Mag for Aqua – Concentrated minerals. Treats shrimp cramps & muscle stress
D-Tox for Aqua – Phosphate Remover
G-Phodo for Aqua
Probiotics
ReeFlowers Bacteria Feeder
Ready Made BioBacteria
Aquarium Bacteria Phosphate Filter Algea
Lodine – Antiseptic – Disinfectant – Povidon Iyot – Baticon Type
A 380 Micro Digest
Magnesium Oxide
Magnesium Chloride
Calcium Chloride
Potassium Chloride
BM – Minerals
Sodium BiCarbonate NAHCO3
Aquarium Salt – Ocean Salt
Ammonia NH3
Sodyum Nitrat NANO2
Triple Super Phosphate (TSP)
Agricultural Lime (CaCO3) for Aqua-Lime – Calcitic Limestone Calcite Agricultural Lime
Urea / H2N-CO-NH2 / Karbamit
MAP / Mono Ammonium Phosphate
Ammonium Chloride
Aquaxi Axyos / Algae and Snail Remover
Aquaxi Clear / Water Clarifing
Aqua Water Regulator / Water Conditioner
Sulfuric Acid / Hydrochloric Acid
Calcium carbonate (CaCO3 ) . Types of lime that can be used
Calcium magnesium carbonate (CaMg(CO3 ) 2 ) . Types of lime that can be used
Magnesium carbonate (MgCO3 ) . Types of lime that can be used
Magnesium hydroxide (Mg(OH2 )) . Types of lime that can be used
For more detailed information, ” Aqua Management Skills Pack ”, Check ” Our Consultancy Terms ”
Lime
When and why do you need to use lime in prawn ponds? Liming is a general term that refers to the application of calcium and/or magnesium oxides or carbonates to ponds for management of the soils and the water column. They can be applied before and during the crop and can be effective in:
Increasing pH (alkalinity) and hardness in the water column .
Guarding against extreme water pH fluctuations (acting as a buffer).
Improving the pH of pond sediments during dry-out periods to reduce disease in the next crop.
Flocculating suspended or soluble organic materials in the water column to improve light penetration.
Accelerating the decomposition of accumulated organic matter.
Improving fertiliser response.
Agricultural lime is normally the best material for treating pond acidity, due to its cost effectiveness, availability and safety.
Quality of water is more important than Quantity