FISH FARMING/FISHCULTURE.
Fish farming/ fish culture is the growing of fish in ponds to allow feeding, breeding, growing and
harvesting in a well planned way without fish escaping.
There are 30,000- 40000 different types of fish in the world that differs in size, shape, habitat and habits.
It’s a form of aquaculture- farming of aquatic organisms in fresh, brackish or salt water.
Other methods of fish farming include; in cages, dams and reservoirs, offshore fish pens and in rice
paddies.
Importance of fish farming.
1. Fish as food
Fish is rich source of protein
The cold liver is vitamin A and D rich
Fish is believed to have less cholesteral than other animal proteins Its
easy to grow
Are cheap than some kind of meat.
It’s available as food all the year round.
2. Better land use
The aim of growing fish, crops or animals is to increase the production of food from land.
When crops have used up all the nutrients in the soil, fish ponds can be built. After afew years the soil will
regain its fertility for the crops to grow again.
Land may not favour crops because it is sandy. But there are ways of building a pond.
Fish ponds can be built as part of the water supply and irrigation.
3. Source of income
A farmer can generate additional income through selling surplus fish.
4. Co-operatives
Fish ponds can be built through co-operatives-an organization of people who come together to do
something they could not or would not do alone. Pupils living close together can co-operate and develop
joint fish ponds.
5. Employment in fishing industries- both direct and indirect
Foreign exchange earner
Recreation–there are certain species of fish that serve the eathestic values like gold fish in
big hotel receptions.
Research
6. Raw materials to industries
Tanning of leather
Cold liver oil for pharmaceutical industries
7. Waste land utilization
Integration:- crop, animal and fish farming- residues of plants like kales and carrots are used for fish
feeding, whole fish produce manure-fertilizer for fish pond
Seeds –replacement in the natural source-fingerlings of extinct species. it is
used for improving quality of fish by hibribidization through genetics
Terminologies used in fish farming.
Capture fisheries -refers to catching fish from their natural habitat e.g. river, lakes, oceans, sea streams.
Culture fisheries- refer to fish produced through human intervention in the organisms’ productivity.
(Artificial habitat) e.g.dams, ponds-man made.
Monoculture- growing of only one kind of fish in a pond.
Polyculture- growing of two or more kinds of fish in the same pond.
Monosex culture- growing of one sex of one species of fish in a pond.
Spawning- the release and fertilization of eggs.
Stocking – the act of placing fish into the pond.
Stocking density- the total number of fish which can be stocked.(Reproduction rate $ food available).
Stocking rate- the number of one species put in a pond.
Classification / Types of fisheries
1. Fresh water fisheries.
Comprises of lakes, rivers, springs (capture and culture fisheries)
There’s permeability of water into fish through:-gills, buccal membrane and alimentary canal because
mineral salts are higher inside fish than outside , hence osmotic pressure is higher inside than outside, thus
water goes inside through the above areas.
Fresh water fisheries which is further divided into inland capture and inland culture fisheries
Limitations of capture fisheries.
It is easier to get fish out of a pond than to catch fish from a river or stream.
Fish growth cannot be controlled by giving extra growth and protection from natural enemies. The
farmer cannot grow only those that he wants.
Does not allow fish farmer to produce cheaply and to have a supply of fish available on his own
land.
Advantages of culture fisheries.
It is easier to get fish out of a pond than to catch fish from a river or stream.
Fish growth can be controlled by giving extra growth and protection from natural enemies. The farmer
will only grow those that he wants.
Allows fish farmer to produce cheaply and to have a supply of fish available on his own land.
Control of water influx
Water influx counteracted through: - dilute urine, a lot of glomeruli, short nephrons.
Examples :Amphilusjacksonii(Cat fish/ Mumi); Anguilla bicolor (Eel/ Mkunga);
Oreochromisniloticus(Tilapia/ Ngege); Protopterusaethiopicus(Lung fish/ Kamongo)
2. Marine fisheries
Inland water fisheries divided into ;
Brackish water fisheries/ back water fisheries.
A mixture of fresh and salt water with fluctuating salinity.
Examples :Shrimp species (Penaeidmonodon $ Penaeidmonoceros); Tilapia; Cyprinuscarpio (Common carp)
and Clarias (Mumi)
2. Marine fisheries
Divided into a)Coastal
marine and
b) off-shoe deep sea fisheries (open water).
Coastal marine fisheries offer a better environment for fish to live because of salinity, light, temperature and
plenty of food. Fish species found are prawns, shrimps, lobsters, and crabs-edible part is tail area.
Marine environment is highly concentrated than inside the fish.
Dehydration counteracted through: - drinking plenty water, gills impermeable to urea;
possestrimethylamine (TMAO); few glomeruli, long, nephrons, gills impermeable to salts and ammonia.
Examples; Sail fish (Sulisuli); Marlin fish, Broad bill fish (Gladiator); Trevally (Karambasi); Tuna; Shark,
Kingfish, Dorado (Falusi), Hag fish.
Classification of fishes
Stanohaline fish
Have limited salt tolerance
Relatively intolerant to salt water changes
Diadromous
Have no salt intolerance and can move from ocean to rivers or vice versa.
Anadromous
Move against current
Spent most of the time in ocean and move to the river to breed.Eg European eel.
Catadromous
Live in the river and later in the ocean to breed
Move along the current
Euryhaline fish
Have a wide salt tolerance
Salt change tolerant
Fresh water fishes
Fresh water has less mineral content
There is tendency of water moving into the fish body to maintain an equilibrium for water balance.
How to control water influx:
The fish should produce a lot of water interms of urine.
Therefore glomeruli counts should be high inorder to increase excretion. To
accommodate this, the kidney size should increase.
The loop of hencle should be shortened together with the convulated tubules. Fish should evacuate 5- 12%
of the their body size in water per day.
Salt balance
Salt are lost through urine, faeces and surface water division
Fish gain salts through active transport through the gill membrane and the oral membrane, and through food
they take
1. Natural habitat
Fish habitat and their management
Mass of water naturally occurring and occupied by fish
Management objectives
Measures should be taken to make sure that the water remains natural
Ensure minimum silt flows into the river. Silt are dangerous to fish because they block the
gills
Fertilizers and chemicals should not be allowed into the river sources. These materials cause
too much vitrification of water and overgrowth of organisms hence less oxygen level.
Chemical may directly injure fish and other animals preying on these animals
Sewage disposal should be managed properly. Sewer leaks into rivers cause death of
animals
Factory effluents most factories emits hot water contaminated with heavy metals like
mercury lead may end up in the bodies of fish
Oil spillage forms ablanket on top of water hence killing all life underneath due to lack of
oxygen, lead is also associated with this.
2. Artificial habitat
Bodies of water which have resulted due to mans effort eg dams ponds and canals
Ponds
Features of a good pond
Made up of walls/ dykes
Fitted with an inlet and an outlet
Might also have a spillage way
Are fitted with screens to keep away things like leaves etc
Have adeep and shallow end
Criteria used for pond site selection
1. Reliable clean water source
Fish depend on water for breathing, eating, growing and reproducing.
Sites with water all year round are the best.(water supply must be constant)
Pond water comes from rainfall, run-off, natural waters, and springs.
Smell, taste and observe water to use.
Very clear water lack nutrients, put fertilizer
Muddy water must settle before reaching the pond.
Dark, smelly and brown water may have acid in it, add lime.
Bright green water has a lot of fish food in it.
2. Soil type
Should not be porous e.g. sandy soil Must
be able to hold water.
Should contain nutrients e.g. iron, calcium and magnesium.
Wet a handful of soil with some water to make it damp, squeeze the soil, if it holds its shape then its good
for a pond
Well constructed pond can also fit the sandy soil.
3. Topography
Refers to land elevation (sloppiness or flatness), built on gently sloping land for ease of filling and
draining off the pond.
Should be near dwelling place e.g. houses for security reason.
Should be near market places to ease transportation and sell fresh fish.
4. Proximity to a market
• Does market demand justify production?
• Will the existing physical infrastructure meet the farmer ’s needs for marketing the fish?
• Will there be sufficient demand nearby or will transporting to a distant market often be a necessity? It
is easier to sell at your doorstep or to have a permanent buyer who takes everything you can produce
and either picks the fish up or is close enough that you can deliver the fish to them.
5. Infrastructure
• Are the roads good enough to bring supplies to the farm and take the product to the market?
• Are telephone service and electrical power available at the site?
w If an intensive production system is necessary due to constraints of space or water, access to power is a
must. Electrical power is about two times cheaper than diesel power in Kenya (2006 prices).
w Telephone service may be needed for ordering supplies, arranging marketing, or requesting
technical assistance.
6. Availability of needed inputs
• Are fertilizers and lime available at reasonable cost?
• Are fingerlings available at a reasonable cost?
• Are fish feeds available for purchase, or are suitable ingredients available so the farmer can produce
his own?
7. Personnel
• Hire qualified people as farm staff. Raising fish requires specific knowledge acquired only through
training. Look for workers who understand farming and are dedicated to a successful operation.
8. Access to Technical Advice
• Be sure good technical advice is readily available. Local extension agents or trained consultants are
good possibilities. Double-check advice received with a qualified individual (meaning they have
produced a few tons of fish before) who is sincerely interested in your success. Good consultants admit
when they don’t know the needed information.
• Consider both criticism and compliments very carefully: The best advice may come in the form of
criticism, and compliments can be misleading.
9. Competition
• Know who your competitors are and how much they sell their fish for. Consider whether you will be
able to match their price and quality or even outsell them by producing a better product or selling at a
lower price.
• If fish demand is high, cooperating with nearby fish producers to market the fish might be a possibility.
The presence of several fish farmers in an area may make it possible for inputs to be obtained less
expensively by forming a purchasing block (cooperative or group).
10. Legal issues
Consider whether or not there are any legal issues that will affect your ability to culture fish at this site.
Would any of the following prevent you from going into fish farming: Land Use Act? Water Act?
Environmental Management and Coordination Act?etc
Pond construction
Planning and design
Some specific design considerations to address include:
1. The source of water used to fill the pond
2. How water will be brought to the pond
3. The type of soil available for building the pond
4. The size, shape, and depth of the pond
5. The slope of the pond bottom
6. The height, width, and slope of the dykes
7. The type of drainage system that will be used
8. The layout (arrangement) of ponds used for different sizes of fish
Steps for Pond Construction
The logical sequence of steps that you should follow to build it. These are:
1. Survey the land
2. Clear all vegetation from the site
3. Remove the topsoil from the site
4. Determine pond, drain pipe, and supply canal elevations
5. Peg out the pond, including core trenches, dyke tops, and dyke toes
6. Dig core trenches and pack them with good soil
7. Excavate the pond area
8. Build the dykes
9. Install the drainage system
10. Install the water supply system
Preparing the fishpond For stocking
1. For an old pond, drain all water from the pond and allow it to dry for a period of fourteen days.
2. Apply lime to the pond bottom and dyke slopes.
•You should always choose agricultural limestone (CaCO3) for application in your
fishpond. But other liming materials, e.g., quick lime or slaked lime can be used.
• Distribute the powder evenly around the pond bottom and on the slopes of the dykes. This
can be done using a shovel. Always wear gloves when working with any kind of lime.
• If necessary, you can also apply lime by spreading it over the water surface
after filling the pond.
3. Apply organic fertilizer to the pond before filling it with water.
The most common examples of organic fertilizers are animal manures (e.g., from cattle, poultry,
donkeys, rabbits, sheep,goats) and decaying plant matter, such as cut grasses.
• Apply the manure to your pond in one of the following ways:
NB Spread dry manure on the pond floor before filling with water. NB Spread
(broadcast) dry manure on water surface periodically.
NB Place dry manure in a crib or compost bin in a corner or along the side of the pond
NB Set sacks filled with manure to float within the pond and shake them daily to allow nutrients to leach
out and enhance water fertility.
NB Construct poultry houses or pig pens above or adjacent to ponds to facilitate easy
movement of the manure to the fishpond
• Apply plant matter in one of the following ways:
oCombine dead plant material with animal manure to form compost,which can
then be applied into pond waters.
oThese materials can also be mixed as compost heaps in cribs in a corner or along
the side of the pond.
oHay and other grasses can also be spread over the pond water as fertilizers.
4. Fill the pond with water.
5. Apply inorganic fertilizer to the pond after it has been filled.
• Inorganic fertilizers, sometimes called “chemical” fertilizers, are manufactured from mineral deposits
for use in land agriculture.
They are usually available from farm input shops in 50- or 100-kg bags. Inorganic fertilizers commonly used
in fishponds in Kenya are Di-Ammonium Phosphate (DAP) and UREA.
• Apply DAP and UREA to your fishpond at the following rates:
oDAP: 2 g/m2/week (or weekly applications of 15 tablespoons DAP for every 100
m2)
oUREA: 3 g/m2/week (or weekly applications of 30 tablespoons urea for every
100 m2)
• Apply inorganic fertilizers to your pond using one of the following methods:
Dissolve the fertilizer in a bucket of water by stirring with a stick and then sprinkle the
solution around pond.
Place small mesh bags of fertilizer on platforms just under the water surface in the
pond, where the material can slowly dissolve and become available to phytoplankton.
Suspend small bags of fertilizer from stakes just under the water surface.
• Do not apply inorganic fertilizers directly to the pond bottom, because important nutrients may be
absorbed by the mud and not be available to benefit your pond.
• Plan to continue applying fertilizers to your pond at the given rates on a weekly basis throughout the
culture period.
• Avoid applying too much fertilizer to your pond, however, as this can lead to water quality problems as
well as higher costs for you.
Types of ponds.
Barrage pond.
Pond is formed by collecting water at the base of the valley and in low places.
Built a wall which holds the water inside what is now the pond area.
Overflow may cause the walls to break. They should not be built where the flow of water is great.
Barrier pond.
Contour ponds –mainly on flat land with poor gradient. Once 1st pond is full water moves to the next.
Diversion pond.
Water from another source like a river or stream is diverted into the pond through the dug channels.
Parallel ponds
Ponds in series.
Building the walls
Walls have to be watertight as well as the pressure of water in the pond.
Strength of wall depends on soil used e.g. mixture of sand and clay is the best. Clay alone cracks
Soil also determines slope of the wall.
Tamp the soil to pack them very tightly hence giving strong walls. Plant
grass and not trees on the walls, trees crack walls after growing. Pond
sealing
Seal the pond bottom so that it does not leak.
Soils with a lot of sealing do not need sealing
Built a clay core into the walls and clay over bottom as lining.
Russian method: use pig dung, apply it at bottom of pond followed by banana leaves or any other
vegetation(easily disintegrate).cover it completely with soil (topsoil) leave it for two to three weeks forming
biological plastic or “grey” and the pond is sealed.
One can also use a polythene bag.
STOCKING THE POND
Stages of fish development
Fertilized egg
Eggs grow and hatch into small fish ( fry)
Fry
Eat tiny plants and animals (planktons), swimming in water.
They range from 2mm to 30mm in length.
Takes 2 to 6 or 8 days depending on type of fish.
Not easily identified.
Fingerlings
Size of person’s finger 4 to 10 cm long.
Have preference to certain food Easily
identified.
Adult fish /brood fish
Sexually mature fish which are chosen as good to spawn (breed) produce eggs and begin the whole cycle
again.
Criteria for fish species’ selection.
Marketability – type and population of fish to keep depends on available market for the
product both locally and international; known and liked as food, requires adequate transport
incase market is far, if near advertise date of harvest, or use tradesmen to buy the fish.
Adaptation - able to reproduce (breed) naturally in your area, able to leave in confinement
(pond), able to find the right food in the pond, relatively free of parasites and diseases, resistant
to diseases and withstand wide temperature ranges.
Productivity- able to grow fast, breed easily in ponds.
Characteristics of a good breeding stock
Average size
Injury, disease and parasite free
Mature in terms of gonads
Lively and active.
Sources of breeding stock.
Natural waters
Fish dealers /fishermen
Other pond owners.
Government fish farms
Transportation of the breeding stock.
Do not handle the fish too much
Make sure the fish get enough oxygen
Keep the fish from getting too warm or too cold
Stock fish in the morning when temperatures are low and fish are less active.
Carry fry in small plastic or metal tubs.
Procedure of stocking the pond.
Conditioning the soil
A layer of lime should be placed on the bottom of the pond evenly, two weeks before water is put.
Why apply Lime
Lime corrects pH to desirable level thus neutralize acidity;
its also anti-parasitic thus clears micro-organisms (sterilization).
It improves soil texture
Types of lime
Ground limestone-1140kg/ha (common)
Agricultural lime – 2270kg/ha
Hydrated lime- 114kg/ha
Quick lime (Cao) -220kg/ha.
Hydrated and quick lime are the easiest to handle
Liming should be done after pond sealing
Pond filling
Introduction of water into the pond
-water should enter through the inlet so that it mixes with oxygen from air as it falls into the pond.
-fill the pond slowly; fast introduction leads to a lot of siltation, leading to turbidity to water
characterized by mud.
Turbidity is the amount of suspended soil particles eg silk particles
- Let water stand for another 2 weeks to encourage primary productivity eg production of planktoms in
the pond
Nb. Unless turbidity disappears primary production will not take place in water. Water should be very
clear to allow sunrays into the pond. In absence of primary productivity, fertilizer is applied.
Water parameters include;
Check the temperature of that water.
-Check both minimum (night) and maximum temperature (day), since every fish spp has specific temperature
e.g. common carp=20-25, grass carp= 25-30, tilapia=25-35.
Parameters of a good pond
1. Check oxygen range using an oxygen meter.
Incase oxygen range goes to or below 4mg/litre then fish is in danger. Normally oxygen range is 6-8
mg/litre.
Incase of 5 mg/litre most fishes exhibit oxygen stress except tilapia.
Oxygen supply should not be less than oxygen consumed.
Any disturbance by man or nature helps put oxygen in water e.g. beating, stirring with stick, small
motors.
2. Check for the PH
Normally best PH is 6.5-9, beyond this, add water to counteract the alkalinity. Incase it’s below, use lime
to neutralize acid.
3. Determine the turbidity of water
Foreign particles suspended, phenomenon of water being not transparent due to presence of particles,
hence prevent penetration of sunlight for phytoplankton’s growth.
Secchi disc is used 2 opposing sides have different colours, allow it to sink in water (it has weight), if the disc
is dipped upto 30cm without colour disappearance turbidity is nil. If colour disappears before depth of
30cm them water is said to be turbid.
Stick your arm under water, if hand disappears when water is at elbow deep, the water is too turbid. If it
disappears before water reaches elbow, it’s very productive. If the entire arm is seen under water, it’s
neither turbid nor productive.
4. Determine water hardness/ saltiness
Hardness is a measure of total salts dissolved in water (calcium and magnesium) help fish to grow.
Phytoplankton also needs these salts for growth.
If water is too soft, increase the hardness by adding lime to water.
5. Check the fertility of the pond
If green colouration (due to phytoplanktons-bloom of algae) has not taken place, then the pond is not
fertile.
Then add some fertilizers.
Stick your arm in the pond, if hand disappears from sight at elbow, the pond need no fertilizer.
Too fertile pond with thick layer of green blocks sunlight from the pond hence no oxygen can be
made by phytoplankton.
Fish require carbon, nitrogen, oxygen, phosphorus, potassium, sulphur, calcium, iron and magnesium
and trace elements. Fish gets these elements from pond soil, the pond water and food they eat.
Application of fertilizers (organic and inorganic)
a)soup farm; place the manure in a container, pour water stir to form soup-like substance then
pour in pond.
b) a crib- a section of the pond is isolated using sticks then manure is poured inside there so that
only fertilizing effect of the manure leaves the isolation and water remains clear.
c) a sack – put manure in a sack and tie , put a stick at the deepest end of the pond and tie the
bag to the stick inside water, the fertilizing effect will be diffusing into water. For large pond apply
manure at the bottom before introducing water.
Application rates:
cow dung 1000kg/ ha;
chicken droppings 114-228kg/ha for new ponds , old ponds require less fertilization
Inorganic are NPK in ratio-8-8-2, 20-20-5; phosphorus is applied in singular form: SSP- 114kk/ha, DSP-
57kg/ha, TSP-38kg/ha
