FISH FARMING
FISH
FARMING
Fish farming in Nigeria has a history of
at least 5 decades it is obvious that our fish requirement cannot be made from
captured fishes alone that entail fish hunting in the wild.
A culture fishery the art of growing
fishes from fingerlings to table size in an enclosed water body is therefore
encouraged.
However, fish farming as an industry is
faced with some problems which include;
·
Insufficient production of fingerlings
of culturable fish species
·
Insufficient number of earth moving
equipments with consequent expensive hiring rates
·
Managers of fish pond farm are unskilled
as most of them are absentee farmers
The following factors have to be
considered before going into fish farming
1.
Fish farmers have to be trained by
experts
2.
Financial aspect
3.
Marketing
4.
Source of good specie of
fingerlings/juvenile
5.
Location
6.
Climatic condition
Importance
of Fish Farming
1.
Fish provides the body with cheap animal
protein which are vital for good health
2.
It supplement other sources of animal
protein that have been on the decline
3.
It serves as a source of income
4.
It creates employment
5.
It serves as raw material
Types
of Culture (pond)
Pond is the place where rearing of fish
and other aquatic organisms’ takes place, the following pond types can be used
to culture fish
1.
Earthen
pond or excavated pond: This is the digging out of the
soul
2.
Surface
or Concrete tank pond: Tank construction is used for
homestead farming and constructed around the home of moderate sizes. They are
usually constructed above the level for gravitational drainage.
3.
Plastic
pond: (water re-circulatory system): This is aquaculture
system in which the majority of water is reused following the removal of
biologically conversion of dissolved ammonia to nitrate. Water quality and
chemistry is often modified before water is returned to the fish and growth is
also faster in this system.
Pond
Construction and Condition
Sites selection is very important in the
construction the following factors should be taken into consideration
·
The dry season is the most suitable time
for pond construction, during this season a seasonal water course is easily
done. It also reduces the risk of sinking heavy machines diversion of water
course is also suitable during this season
·
Avoid areas where there are trees rocks
and termites
·
Construct the pond or tank close to a
regular source of water
·
The pond most not be far from home or
the attendant house
·
Pond should be constructed in a location
where the soil is not sandy to avoid excessive seepage heavy clay soils are not
good.
Maintenance
of Earthen Pond
1.
Apply lime construction (earthen pond)
2.
Plants
carpet grass at the dyke of the pond to avoid erosion
3.
After the application of lime their
fertilization
4.
Stocking of fish should be done after
two weeks of fertilizer application
5.
Cutting of grass to a lawn condition
should be done to avoid predators
6.
Don’t allow too much of water hyacinth
in the pond and remove any weed inside the pond
7.
Always check the water level in case it
drops too low
8.
Acrate the water if possible
9.
In terms of outbreak of disease consult
a professional in the field
Concrete
pond maintenance
1.
After construction put water to the brim
and leave for about two weeks to remove any toxicant. The water should be
accompanied with organic manure e.g poultry droppings
2.
These water should be discharge and new
ones to be impounded
3.
For pond water that is recycled its
takes about 2 – 3 weeks before changing it. But non recycled one water should
be dropped every 2 – 3 days for about 50 – 60% and impound fresh water.
4.
In case the water is highly turbid total
drain out should be done
5.
Always clean inside the ponds with the
aid of sponge and brush to avoid too much algae bloom
6.
Roofing of the pond could be done if
possible.
Ways
to predict soil suitability
Squeeze Method:
wet the soil, squeeze and hold it in shape if it forms shapes easily then a
pond can be built there.
Ground Water test Method:
Dig a hole to a depth of about 1m and cover it with leaves for one night to
limit evaporation if the hole is filled with water the next morning the pond
could be constructed.
Water permeability test:
The land contour and the land shape determine the rate of water permeability.
The test should be performed at the end of the rainy season when the soil is
still soft and water near maximum levels.
Procurement
of Fingerlings/Juvenile
Generally there are two sources
(a)
Wild collection
(b)
Hatchery production
Supply from wild is unreliable therefore
our hope for sufficient fingerlings/juvenile depends on hatchery production.
Water
Quality Management
Dissolved Oxygen:
Apart from water itself dissolved oxygen is the fundamental parameter to fish,
oxygen is essential to organisms for aerobic operation 90% of organisms are aerobic
thus the solution of oxygen and its dynamics is a basic thing in fish culture.
Dissolve oxygen has a lot of influence
on the distribution behaviour of physiological growth of fish. The atmospheric air
consists of 21% of oxygen but only a slight amount can dissolve into the fresh
water environment.
The following are factors that affect
the solution in water
Ø Temperature
Ø Atmospheric
Ø Pressure
Ø Salinity
Ø Turbidity
Ø Sunlight
The solubility of oxygen in water is
affected normally with temperature as solubility increases the water
temperature decreases, that’s to say that colder water contains more oxygen
than warmer water
Sources
of dissolved oxygen
1.
The most important is photosynthesis it
is produced by phyto planktons and other aquatic oxygen plants as a result of
chlorophyll
2.
atmospheric air (21%) therefore part of
it is able to find itself through water by diffusion
3.
Artificially through the use of aerators
Uses
of Dissolve oxygen
1.
Through respiration by phytoplankton,
aquatic plants and aquatic animals especially fish
2.
Decomposition of organic matter
3.
The rate of oxygen production by
photosynthesis reduces with depth because light does not go beyond euphotic
zone
Effect
of Low D. O
1.
Stoppage of feeding or decrease in
feeding
2.
Reduce actives
3.
Growth reduction
4.
Susceptibility of diseases
5.
Causes stress and mortality
Measurement
of D. O
1.
Winkler titrimetric method
2.
Use of D. O Metre
Signs
of low D. O
1.
Sudden change of colour of phytoplankton
from green to brown
2.
Snails crawls up the grasses stem and
sides of the dyke early in the morning
3.
Reduction and stoppage of feeding by
fish
4.
Appearance of black oily streak on water
surface
5.
Rotting smell of H2S at an advance stage
Fish
Diseases
Several factors influence the
transmission and distribution of diseases in fishes. Since fish are aquatic in
nature water is therefore the principal medium for disease transmission and
distribution.
Basically, any factor which causes
stress or difficulty to the fish decreases its resistance to disease and
increases the chances of diseased problems occurring. These factors are
environmental stresses.
(a)
Poor water quality
(b)
High stocking density/overcrowding
(c)
Poor handling of fish
(d)
Improper feeding
Transmission of diseases occur in two
principal ways
1.
Horizontal transmission e.g infectious
abdominal dropsy (IAD)
2.
Vertical transmission e.g bacterial
kidney diseases (BKD)
Physical
Signs of Diseases in Fishes
Ø Gapping
mouth
Ø Open
sores, lesions bloated and discolouration of body
Ø Protusion
of eye balls
Ø Folding
of fin, erosion, swelling and colouration of gills
Ø Presence
of disease organism on skin, gill and fins
Ø Apathy
(Lack of appetite) and disease or stoppage of feeding
Ø Lack
of response to freight stimuli
Ø Scratching
or rubbing of body part against hard object
Ø Excessive
mucour secretion on skin and gills due to irritation
Bacterial
Disease
External
clinical symptoms: Erythema (Redding of mouth, fin and fin
base exoplihatmia ulcerative necrosis of skin, swollen abdomen.
Internally:
swollen of kidney, liver becomes pale, petechial haemottages of peritoneum, and
visceral organs in extreme acute infections there may be high mortality without
disease signs.
Treatment
control and prevention
Prevention measures include avoiding
stress factor e.g poor handling, poor water quality and stocking unhealthy
fish.
Treatment
involves
Uses
of antibiotics
1.
Immersion in chlorophyll, 13mg/L of
water for 3 – 9 days for low dosage or 50mg/l of water for 1 day for high
dosage, fish must be at least 10kg.
2.
Intraperitonial injection at rate of 1 –
5ml/100kg of fish and fish should not be feed when administering the
chlorophenicol
3.
Oral chemotherapy by mixing drug with
fed at the rate of 1mg/100mg fish is also effective
Fungi
disease
Presence of fluffy whitish grey cotton
or blotches or injured wounds of fish
Treatment
and control
1.
Correct environmental factor
2.
Use of disinfectant
Disinfectant
to be used
1.
Malachite green 5mg/l for 1 hour
2.
5% Nacl per litre of water
Viral
Diseases
At fingerlings stage (3.5g) sign of
rupture in the caudal part of intestine known as “Rupture intestine syndrome”
Destruction of absorbent organ (air breathing organs) lead to inflammation of
the skin resulting to lateral skull break. It is known as “Broken head
Diseases”.
Treatment
and control
Quarantine fish before stocking control high
laboratory examination of faeces, eggs and fry for screening before stocking,
there is no effective treatment because it is highly contagious
Feeding
1.
Do not feed your fish less than three times
daily
2.
When feeding ensure that they are eating
the feed
3.
Stop applying the feed when there is no
response
4.
Feeding should be three to four hours
internal
5.
Do not feed your fish with anything that
is too oily
6.
Do not feed your fish immediately you evacuate the
water allowed for about 30 minutes to one hour
7.
For re-circulatory system stop the
system before feeding
8.
Consult a professional if the fish do
not respond to feed completely
9.
Floating pellet is more preferable than
sinking pellet
Economic
of Production
Estimation
of feeds and expenses
Stage
|
Feeds
size
|
No
of fish
|
Consumption
|
Time
|
Juvenile
|
2mm
|
1,000
|
1bag/month
|
Three times daily
|
Post juvenile
|
3mm
|
1,000
|
2bags/month
|
Three times daily
|
Pre adult
|
4.5mm
|
1,000
|
2.5bags/month
|
Three times daily
|
Adult
|
6mm & above
|
1,000
|
3-4bags/month
|
Three times daily
|
At the end of production 1kg can be sold
at N400 or N500 depending on the bargain, drugs to be used in cases of
outbreak or to effect faster growth will amount to about N10, 000 throughout the culture period. There could also be
variation in feeds prices. Fingerlings are sold at N20 per piece while juvenile N30
per piece.
Estimation of feeds and other expenses
from juvenile catfish to table size (adult) for one set of water re-circulatory
system
Name of fish size
Name
of fish
|
Size/age
|
Size
of the feed
|
No.
of the fish
|
Duration/Qty
of consumption
|
Time
of feeding
|
Juvenile
|
5-6wks
|
2mm
|
1,200
|
1bag/1month
|
3
times daily
|
Post juvenile
|
21/2months
|
3mm
|
1,200
|
11/2bags/1month
|
”
|
Before adult
|
4 months
|
4.5mm
|
1,200
|
2bags/1month
|
”
|
Adult
|
5 month & above
|
6mm & above
|
1,200
|
3 to 4 bags per month
|
”
|
The recommended feed is coppens feed,
the smaller the size the higher the price e.g 2mm is N6, 200 while 4.5 is N6,
000.00. Drugs administration depend on extend at which they are infected with
disease but it is advisable to prevent them from disease by using drugs like
fish biotic, fishvit e.t.c.
If the fish are properly managed i.e
washing of the pond regularly, changing of water as at when due, feeding them
normally, giving them drugs at the right time, one can achieve 1kg of each fish
after five months and experience less or few mortality i.e out of 1,200
juveniles one can record 50 mortalities.
At the end of production 1kg can be sold
at the rate of N450 or N500 and above, this depends on the
market. Besides, a fish farmer cannot realize all his money at the end of first
production due to the expenses he made during construction of the pond, buying
of drugs and feeds and other expenses.
Calculation
of the expenses
1,200 juveniles (40 per 1) - N48,000.00
Feeds (9 bags) - N54, 200.00
Drugs - N10,000.00
1 set of water re-circulatory system - N375, 000.00 (for registered
client)
Calculation
for selling
1150 (survivals) x N500 - N576,
000.00
Calculation
for profit
Total amount of selling - N575, 000.00
Total amount of expenses - N487, 200.00
Production)
Comments
Post a Comment