WATER MANAGEMENT IN
FISH FARMING
Water is the basic factor decides the life and growth of the
fishes stocked in it. For culture fish to perform well, good quality water must
be guaranteed. Water quality are parameters or characteristics either physical,
chemical or biological of water body which determine the suitability of it for
fish production and other culture species e.g. shrimps prawn.
Water qualities usually induce by the water;
·
Source
·
Location
·
Nutrient level
·
The component organisms
Thus, it become essential to make detail PHYSICO-CHEMICAL and BIOLOGICAL analysis of water to access
the quality of the water to be used before the establishment of a fish farm.
Water quality maintenance is a primary concern for a fish
culturist because the poor management of his pond may result in high mortality
of the culture species. For example if there’s sudden reduction in oxygen
content of the water or sharp decrease in the PH the culture fish would be
stressed –up and proned to disease and poor growth rate.
WATER QUALITY AND QUANTITY DETERMINE
STOCK – DENSITY
The available water quality and quantity is the predetermine
factor of fish which can be produced.
To achieve calculated profit pond, water must be well
managed and sustained. A fish farmer should consult only professional aqua
culturist or limnology in the initial setting up period to determine the
various level of the important water quality parameter of his pond. And how to
manage it for result. The most important water parameters to be considered for
fish production are:
1.
Dissolved oxygen (3mg/l to saluration)
2.
PH
3.
SALINITY (SALT CONTENT) 0.5
4.
Water
Temperature 25-30oc
5.
Ammonia <0.002
6.
General hardness 20-80
7.
Carbonate hardness 20-80
8.
Chlorine <0.003
9.
Turbidity 30-50cm (light penetration)
10.
Hydrogen sulphide <0.003
11.
Total dissolved solid (TDS) <200mg/l
12.
Total suspended solid (TSS) <50
13.
Fe 0.00
14.
Microbial levels (Pathogen)
However, it is necessary to bear it in mind that various
parameter internet with other.
MONITORING AND MAINTAINANCE GOOD
QUALITY POND WATER
PH Factor :- Degree of alkalinity and acidic of the pond is
very crucial as it will have influence on other factors. Generally, fish
performance well in the PH range of 6.7-8.6 and below or above the range
inhabit growth and production, the extend of this depend on the species
cultured and control condition. The death points are approximately below and
above PH 4 and PH 11, Critical minimum PH level for most fish to survive is 4.5
Acidic water affects production, for instance Tilapia would
refuse to fecund at low PH. Low Ph reduces oxidation of plant and animal by
balancing activity.
Water containing Fe(iron) above 0.9ppm would rise the PH to
5.5 because Fe are hydroxide deposited on the fish gills thereby suffocating
the fish and death results. Any sudden change in the PH indirectly affect the
fish by instituting the onset of stress condition which lower the fish immunity
and predispose the fish to clinical and sub clinical condition.
CORRECTING POND WATER
PH
In fish farming industrials polluted water should be avoided
in totally except when treated which add more to the cost.
LIMING:-PH of
pond water is better corrected by the application of lime. However, water
analysis is imperative in order to know the quality of lime needed to correct
the water PH. Factor determine the dose
of lime to be applied are:- Ph level of the water (2) Chemical composition of
the liming material (3) Type of the Lime
HANDS ON PRACIUCAL IN
BREEDING OF CATFISH
Induced breading and artificial
fertilization in clarias gariepinus
collection of brood stock- parent fishes – sources
Natural culture
Selection of brood fish
– for successful breeding
Genital pore Female – well
round soft abdomen
Reddish & projected
Male
– elongated and slender in shape
Genital papilla elongated
Rearing of brood fish
Water quality Nutrient
Inducement – why
Hormone injection
Ova tide @ 0.5ml/kg
After
10 hrs stripping of ripe eggs
Sacrifices the male and
dissection out of tests (milt) from male
Over the Dilute in 0.9%saline
solution spread
Collected eggs
Min Artificial fertilization – Mix well-allow 2
minutes – mix for 5
Egg
+ milt
Fertilization eggs are spread in single layer in the
hatching tank
The eggs Allow
gentle water flow –not to disturb
Egg will hatch out after 24-36 hours depending on the
temperature
Feeding commences 72
hrs after hatching – when the mouth is seen
(i) artemia (ii) Daphnia (iii) Rotifers (iv)
Mino
Dead egg should be
removed in the process of development
Rearing the fry in the
hatchery
FILTRATION AND FILTER
APPARATUS IN INTENSIVE FISH FARMING.
Why
filtration is essential in intensive fish farming?
Intensive fish farming involve the two
following things
1.
High stocking density of fish per sq.m,
resulting in the high biomass per cu.m of water
2.
High feeding rate with great quantum of feed- to
feed the fishes in the tank.
These two things lead to the following conditions in the
tank water:
1.
High production of fecal matter from the fishes
2.
Uneaten feed and dissolved feed particles in the
water
3.
High release of CO2 through respiration
4.
High intake of Oxygen from the water by the
fishes
5.
High production of nitrogenous waste such as
Ammonia and Nitrogen compound through the urine, fecal matter, decomposition of
high protein feeds and through microbial decomposition ( enzymes from microbes
and fecal enzymes).
6.
Enriched mucus secreted by the fish body
The above condition and enriched matter make the water unfit
for the fishes. This makes the Fishes to undergo great street and changes in
the body physiology so as to use much of the energy ingested to maintain the
body growth .
So the ultimate results are – (1) Poor growth or no growth,
(2) Disease outbreak due to varied microbial colonies develop in the water due
to accumulation o impurities, and (3) Sudden mass mortality.
To avoid all the above adverse conditions, it is necessary
to keep the water lean. Cleaning the tank and providing good and favorable
culture conditions is possible in two ways
1.
Completely changing the water almost daily
2.
Filtering the water and reuse
Advantages and
Disadvantages of both the method
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The complete exchange of water
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Merits
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Demerits
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Completely pure water available for the fishes daily
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The change is done only after accumulation of the wastes. So the
fishes have to live in the bad water for more time before getting the pure
water
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Ensures good living environment for the fishes
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Change of water involves considerable expenses everyday
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Change of water causes considerable stress to the fishes due to
complete removal of the water.
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The basic ecosystem is disturbed so that the natural conditions have
to be created every time changing the water
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The major reason is that the mineral and vitamins leached into the
water during the feeding and decomposition of the fecal matter will be lost
when water is drained out daily
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The filtration of tank water
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Merits
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Demerits
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Filtration gives a continuous movement of the water, which is
considered good for the fishes as that of the running water (steam).
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Filtration process involves apparatus and equipment necessary for
different types o filtration. So it involves cost .
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Ensures good living environment for the fishes through the water
movement. The waste accumulated is removed then and there so the fishes do
not expose to waste accumulated conditions
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Continuous monitoring of the filters is necessary choking of the
filters and pipelines should be avoided through continuous monitoring.
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The oxygenated due to the water splashing in the filtration process
help the loading of oxygen in the tank
water
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There will be a loss of water up to 5% everyday which should be
compensated
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Completely pure water available for the fishes continuously without
any break.
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No stress for the fishes as they are not kept out of water any time
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The natural condition is preserved as the same water is used
continuously
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The system is always rich in oxygen with reduced nitrogenous and
gaseous wastes
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The bio-filter oxidizes the nitrogenous waste to very useful nitrates
thereby the nutrients are enriched in the system for the fishes
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The UV radiation and ozone treatment help the water to be free from
all germs and pathogens as they kill all the micro organisms
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The mineral and vitamins leached into the water during the feeding
and decomposition of the fecal matter will be available to the fishes always,
as this water is not removed from the system.
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So it is clear from the above that filtration of the tank
water is better for the intensive farming of fishes over the change of water
daily and therefore
What are the components of a filtration
system in the intensive farming ?
The following are the components of a filtration system in
the intensive fish farming
1.
Screen
filter – to remove the big solid matter – not necessary for the system
where feed alone is the daily input.
2.
Sediment
filter- to remove the suspended solid matter (fecal matter. Uneaten feed,
etc in colloidal mass) – This can be either sedimentation chamber or rotary
filter or drum filter or multiple screen filter or fluidized bed or rapid flow
sand filter or any suitable filter.,
3.
Clarifiers
– to clarify the water and reduce the mineral and element level in the water accumulating
due to various biological and biochemical activities
4.
Bio
filter- to remove the dissolved gases and ammonia –very much necessary
where high nitrogen matter (high protein ) is used – This can be achieved
through fabricated bio-filter or bead filter loaded with beneficial microbes
5.
UV
irradiation – to kill the bacteria, fungi and viral pathogens in the water
6.
Ozonation
– to kill the germs and oxidize the dissolved organic matter so that the load
or organic carbon is reduced drastically.
7.
PH. Adjuster
- to keep the Ph in optimum level of 8.2
to 8.5 for better growth and metabolism
In addition to the above, sponge
filter to remove the solids can also be used in the place of Screen filter
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How the filtration system is fabricated (water flow
chart) in the intensive fish farm.
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What are the principle that are being
adopted in the filtration system in then intensive fish farming of fishes and
what are the advantages of the principles and the apparatus used for tat
The principles used/applied in the filtration system are,
1.
Removal of coarse suspended matter – this is
done by screen or sponge filter.
2.
Removal of fine suspended matter – this is done
in sedimentation tank of rotary belt filter, drum filter or sand filter.
3.
Removal of minerals and elements –this is done
by clarifiers
4.
Removal of harmful gases and ammonia – this is
done by bio – filtration
5. Remove of
harmful bacteria’s and other micro organism – done by UV radiation and Ozonation.
The advantages of the principle:
1. All
the above principle is with application of the only physical and biological
method of filtration and not the chemical methods. This is the greatest
advantage, as the water filtration will not have any harmful chemicals.
2. The
water is pure as that of fresh new water without any micro organisms like
bacteria, fungi and viruses.
3. The
water is enriched with nutrients (nitrates) after bio – filtration, which will
be more harmful for the fishes.
4. Oxygen
is enriched in the water, so that anaerobic condition will not arise in the
water.
How the different
filter component are useful in the intensive fish farming.
Screen / Sponge filter: This filter is less applied in the
intensive fish farming rearing system, as this filter is much used in the
sewage and surface water filtering, which may contain big floating or coarse
suspending materials.
Sediment filter: The major function of this filter is the fine and
tiny suspended solids can be removed by the process called “sedimentation “The
multi chambered sediment tanks constructed below the bottom level of the
culture thanks affect this .This positioning will give the higher velocity for
the water flowing into the chamber, which will enhance the settling of the
solid particles. The heavier solid particles are sedimented in the first and second chambers of the tanks
and the clear water from the top is allowed to go to the next chamber for
further clarification.
Clarifiers: This is generally not required for the low level
intensive fish farming operations, particularly when the catfishes are reared,
as they can tolerate high minerals in the water. But most effective in the case
of intensive fish farming of the Tilapia and Bass. Naturally aquatic plant will
be used in the tank for the removal and clarification of the fish tank water
after removal of solids.
Bio – filters: The most important components in any water filtration
system, as it alone remove the dissolved gasses and harmful ammonia from the
water.
The fish tank water is, by nature
loaded with the gasses (CO2 ) due to respiration and ammonia ( NH3 ) as the
resultant product of the excretion . In addition to the above harmful gasses
like H2S and SO2 are also added to the water due to microbial degradation of
the organic matter. These gasses are VERY HARMFUL to the fishes as they are not
to be expected to the conditions. Therefore they are to be removed.
In bio – filters, first the water will be passed through the wool
filter or sand filter to remove the tiny particles, which might not be
deposited in the sedimentation chamber .After this, the water will be allowed
to pass through the activated charcoal (activated carbon) The minute pores and
large surface area in the charcoal helps in the absorption of the gasses from
the water thereby the gasses are removed.
After this the water will be
passed through ceramic rings or ceramic tubes, which will remove any excess gasses
left by the charcoal. After the complete removal of the gasses, the water is
passed through bio – media (bio – balls or bio – fibers or bio – coils). The
Nitrifying bacteria’s such as nitrosomonas and nitrobacter present in the
bio-media will oxidize the ammonia in the water to nitrite and then nitrates.
Thus the water is fully cleaned of all obnoxious gases and ammonia. After the
water will be allowed to pass the UV chamber.
UV Radiation: The water will be passed over the UV light inside the
UV chamber, where the UV radiation will kill the bacteria that might be carried
in the water. This is a disinfecting action.
Ozonation: Ozone generated in the ozone processor will be supplied
into the water so that all the germs and cysts will be killed. (Ozone is a
highly reactive gas, which will penetrate into the cells of the micro-organism
and kill them) In addition to the disinfection, the dissolved organic matter in
the water will be removed by the oxidation property of the ozone. This is an
additional disinfection measure, which will ensure removal of all pathogens
completely and enrich the system with oxygen for oxidation of the organic
matter.
Ph Adjuster: This is an optional component in the filtration
system, when the PH of the water is tilted to unfavorable level. Due to the
loading of so much organic matter, the resultant decomposed products shift the
PH to lower level (about 6 to 7) The basic PH (8.5) should be restored for
better growth of fishes by adding the diluted basic solution. However, only based
on water quantity this will be added in the filtration system.
FEEDING PRACTICE AND
SPECIFICATION
Culture Days Expected
Weight Feed
Type
20 – 45 50 – 100g CP 58% Fat 12%
45 – 65 105 – 250g CP 46% Fat 12%
66 – 85 250 – 500g CP 46% Fat 12%
85 – 105 500 – 750g CP 40% Fat 10%
106 – 125 750 – 1000g CP 35% Fat 8%
126 – 145 > – 1000g CP 30% Fat 8%
1. This recommendation is based on optimal water quality
(PH, 02) Nitrate and Ammonia level and right stock density and temperature.
2. This specification is only a guideline for using DARMO –
AQUAMASTER feel formula.
3. Feeding and feed could be adjusted based on water factors
and growth performances.
4. Water management is most singular factor for feed cost
benefit.
5. Give your fish split feeding 31/2 hrs, 2 hrs for adult,
young fish respectively.
6. Consult only experienced aqua cultural professional for
effective design and management practices.
7. Stock your pond with quality fish seed from a reputable
hatchery.
POND CONSTRUCTION ENGINEERING
VOLUME 1
FLOW –THROUGH POND
DESIGN AND CONSTRUCTION
BASIC PRINCIPLE
FLOW THROUGH TANK CULTURE SYSTEM:
Flow –Through Culture System: is a simple technology where
by water will be coming in and going out of the tank. It could be made of block
or concrete.
In this system the pond is constructed with either block or
concrete with the necessary facilities.
The pond could be subrnerged or surface type. However, the
surface tank is preferable for cost effective water drainage.
The system is simple to manage and homestead type. It has
the following advantage
ADVANTAGE OF FLOW – THROUGH TANK
CONSTRUCTION SYSTEM
1.
Its cost effective where there is cheap source
of water
2.
No loss of water due to seepage. Only
evaporation loss
3.
All a biotic factors can be controlled and checked
4.
Predators could be totally eliminated
5.
Complete control over the stock is possible
6.
Medication or
the therapeutic attempts will be very possible
7.
Stock density is higher 50-100 fish/m3
DISADVANTAGE OF FLOW - THROUGH TANK CONSTRUCTION SYSTEM
1.
More skilled management and technical knowledge
is essential achieve success in the farming
2.
All nutrients need to be supplies
3.
Water discharge problem
LAND
The topography of the soil must be considered. Physical
features of the soil like soil structure, texture
ENGINEERING DESIGN
AND POND CONTRUCTION
A modern and complete catfish pond is composed of different
units
1.
Brood fish tank
2.
Hatchery tanks
3.
Nursery and fingerling rearing tanks
4.
Grow – out production tank
BROOD STOCK FISH TANKS
The brood stocks, which product for starting new generation
of fish, must be adequately catered for. Smaller ponds are advisable for easy
harvesting and selection of the brooders. Pond size of 200m2 – 100m2 is recommended.
However the number,size and species of brooder in choice of the size of the
pond.
For concrete or hollow blocks tank –a dimension of 6m*1.5m*1.5m
could be adequate in the concrete tanks, water parameter must be monitored
regular for good result.
Brood fishpond should be located where good security is and
does not involve transportation problem during operation.
HATCHERY TANKS
This is a collection of tanks or containers where ripe
breeders for induced spawning are kept. It could be made from wooden plank,
concrete or glass fibre or plastic bowl.
The bottom of the basin should slope gradually toward drain (outlet) turndown
pipe should be fixed for regulating the water level.
(1*0.680.40) m for 3-4 brooders will be adequate. Here the
fish can easily be taken for stripping without too much disturbance.
INCUBATION TANK
Construct the pond with concrete, wooden or fiberglass
materials ease of management, a dimension of 3m* 1m * 0.3m will be adequate.
The floor should slope gently toward the outlet fixed with turn- down or
adjustable pipe for easy drainage
NURSERY TANKS (PONDS)
The number of thanks to be constructed depends on the scope
of the project. It could also be constructed with concrete (blocks, graveled
cement) wooden or fiberglass material. A dimension of (3*2.5*0.6) m this will
take a minimum of 10,000 fingerlings at stocking density of 1300
fingerlings/sqm. Like the other tanks it should be sloped gently towards
outlets – the tank should also be provided with shade.
GROW –OUT TANKS/POND
The grow out pond may be earthen pond or concrete or
fiberglass pond. A grow out concrete wall. A dimension of (6*1.5*1.5) m is
suitable for 1500- 1600 fish up to table size of 1kg. a breath of 1.5m was
chosen to allow for easy cleaning of feed remnant as solid waste during water
change. The bottom of the pond should be slope by 11 inches towards the outlet.
All the corner of the pond that is right angle be rounded off to enhance self
–cleaning in the tank.
The following procedure could be used as a guide in
constructing concrete as fishponds
ü
Select the site and clear
ü
Peg out the desired dimension of hatchery,
nursery or grow out and demarcate using twine or rope
ü
Dig up the foundation by removing the topsoil of
humus and organic debris until a solid sub soil is obtained. It could between 6
inches to 1 –foot depth.
ü
Do the binding of the floor by pouring a
concrete mixture of cement, sand and gravel mixed water in the ratio 1:2:4 and
one of 2kg pudlo waterproof cement and make the thickness to be between 3-6
inches. Allow to dry for one week. The should be larger than the tank for
distribution of weight
ü
Make block wall along the 4 sides of the pond
rising 6 or 9 inches specially made (i.e mould 18-22 blocks from one bag of
cement) the wall should be extended to maximum height to 30cm, 60cm or 150cm
for hatchery, nursery grow out tank respectively
ü
During flooring slope the tank towards the
outlet by eleven inches using the same concrete mixture mentioned above
ü
Lay 1 or 4 inches diameter P.V.C as the case may
be as drainage pipe at the outlet. Attached with elbow and screen and let it
terminate outside the tank as turn down o adjustable pipe such that it can be used
as discharge pipe for varying water level (flow through system)
Fill the hollows of the block with
concrete and plaster both inner and outer walls of the tank (pond). The
Thickness of the plastering should be 1 inch using a mixing ratio of 1 one bag of
cement to 6 head pans of sand and 2 bags pudlo waterproof cement. Allow the
tank to dry out slowly by providing it with shade while wetting daily twice for
a week.
TANKS WITH CONCRETE
WALLS
Where concrete wall is used, the
entire walls and base must be reinforced with rod. The reinforcement material
should have continuity with that if the walls. Plastering must have smooth
surface and the right angled joints should be rounded off it makes cleaning
easier and algae, bacterial and protozoan growth
Ø
Concrete pouring work must be continued until it
is completed day so that concrete does not dry out in section. As this could
result in cracks and leakages later at the various point
Ø
It is important to cure or age new tank before
usage. This is done by filling the tank with water and placed bags of poultry
dropping into it and allows to stand for two weeks. The resultant algae bloom
and the change of water will wash away the toxic materials of the cement in the
tank if the curing is not proper, process could be repeated for another two
weeks.
Ø
The ponds should be provided with roofs to
shield it form direct sunlight which could lead to unhealthy fluctuations in
the temperature of the pond water
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