1) The document discusses aquaculture (fish farming), including definitions, the importance of fish farming due to overfishing, and common fish farming techniques like extensive, intensive and semi-intensive farming. 2) It provides guidance on site selection, pond construction and design, including pond size and shape, depth, building dikes, and including water inlets and outlets. 3) The document outlines best practices for pond management, including fertilizing, liming, feeding fish, stocking, and monitoring and maintaining good water quality. It emphasizes the importance of record keeping for fish farm operations and profitability.

1. CHAPTER THREE
AQUACULTURE (FISH FARMING/CULTURE)
Learning Objectives
• To understand the importance of fish farming
• To learn method fish pond construction
• To recognize value own fish farm
• To learn fish pond management and its purpose

2. Introduction (Cont…)
Definition
 Aquaculture is the production of all forms of aquatic animals such
as fish and crustaceans or aquatic plants such as algae in fresh,
brackish or salt water.
 Or aquaculture is the ‘‘cultivation of plants or breeding of animals
in water
 A primary goal of aquaculturists has been to produce food for
human consumption.

3. Introduction (Contd..)
 Throughout the centuries fish has been an important component of
the population’s diet
 Fish catches increased rapidly over the past hundred years leading to
 Overfishing and
 Reduction of wild fish resource
Hence, growth in fish catches stopped some 20 years ago
 Leading to fish farming/aquaculture to improve productivity of fish
 Aquaculture increased fish production from 3.9 in 1970 to 31.9%in
2003 (FAO, 2005).
 Aquaculture is becoming common in Africa

4. Introduction (Contd..)
Fish farming techniques include:
• Removal of unwanted plants and animals
• Replacement by desirable species of fish
• Improvement of these species by crossbreeding and selection
• Increase of nutrient availability by the use of fertilizers and feeds

5. Introduction (Contd…)
Advantage of fish
 Fish provides high quality animal protein for human consumption
 A farmer can often integrate fish farming into the existing farm to create
additional income and improve its water management
 Fish growth in ponds can be controlled: the farmers themselves select the
fish species they wish to raise
 The fish produced in a pond are the owner's property thus; they are secure
and can be harvested at will
 Fish in a pond are usually close at hand
 Effective land use: effective use of marginal land e.g. land that is too poor,
or too costly to drain for agriculture can be profitably devoted to fish
farming provided that it is suitably prepared

6. 3.2.Types of fish farming
I. Extensive fish farming
 The fish production relies merely on the natural productivity of the water
 Inputs are limited
 Costs are kept low
 Capital investment is restricted
 The quantity of fish produced per unit area is low
II. Intensive fish farming
 Feed, quality of water and quality of stocked fingerlings, are controlled to
improve the production conditions.
 High technology and production cost
 Contribution of natural food is very low
III. Semi-intensive: moderate level of inputs

7. 3.3.Site Selection for Pond Culture
Choosing an appropriate location for the ponds is essential to ensure
 permanent provision of water
 minimize construction costs
 allow easy management and avoid loss of water through seepage.
Thus, the following points to be considered during site selection
Location:-
 ponds should be placed near the home or the village.
 Site should be accessible at all times and not subject to occasional
flooding
Proximity to a water source
 Proximity of a permanent water source
Topography:
 Ideally the ponds are placed on a slight slope
 A slight slope of 1 to 4 % is advantageous

8. Site Selection for Pond Culture (Cont…)
Soil properties:
Minima water permeability
There are three methods to test the suitability of the ground:
(i) Seepage test: dig a hole and see, if the soil holds the water
overnight to at least 90 %.
(ii) Squeeze method /Press some soil in the hand to see if its stability
is good
(iii) Rub the soil between your hands to distinguish between clay and
silt. If all tests are positive, you can begin to plan the dimensions
of your ponds.

9. Guidelines for pond design and construction (Contd…)
Size and Shape
 Square and rectangular shaped ponds are easiest to build
 An area of 300 m² is a good size for a family pond
Depth
 The water depth is usually 30 cm at the shallow end and 1metre at
the deep end
 The pond can be deeper than this if the pond is used as a water
reservoir in the dry season

10. Guidelines for pond design and construction (Contd…)
Building the fish pond
Most difficult and most expensive part of fish farming
1. Prepare the site: Remove the trees, bush, top soil, and stake the
area
2. Dig the pond and build the dikes: Use soil and compact very well.
Should be about 30cm above water and 50cm for cat fish
3. Build the inlet and outlet: A canal to bring water to silt catchment
and pipe to take to pond and outlet is to drain water from the pond
and should be screed

11. Guidelines for pond design and construction (Contd…)
1.The water inlet
Consists of
• a canal to bring in the water
A silt catchment basin:
 silt catchment basin will prevent this soil from entering the pond
A pipe to carry water into the pond:
 this pipe runs from the catchment basin through the pond dike into the
pond
 should be about 15 cm above the water level
 prevent fish from escaping by swimming into the inlet pipe
 It also helps to mix air into the water
2.The outlet (also called drainage pipe)
 is screened inside the pond to stop fish from escaping
 Screens can be made from many types of materials
 Anything will do that allows water but not small fish to pass through.

12. Guidelines for pond design and construction (Contd…)
3.Protect the pond dikes:
 Plant grass such as Rhodes grass and star grass on the dikes
 Do not use plants with long roots or trees
 Use fertile topsoil will help the new grass to grow
 The grass will help to protect the dikes from erosion
4.Fertilizing the pond
 Enhance the productivity of the pond
 Manure, compost or chemical fertilizers can be used
 Will ensure a continuous production of natural fish food
 In acid, use 10-20 kg of lime or 20-40 kg for each 100 m² of pond
bottom.

13. Guidelines for pond design and construction (Contd…)
5.Fill the pond with water
 Fill the pond slowly so that the dikes do not subside due to uneven
wetting
 Do not fill the pond too full
 Water in the pond should not flow through
 The only water added to the pond should be to compensate for
water loss through evaporation
 New ponds often seep when they are filled with water for the first
time as the soil partly takes up the water
 Keep adding new water for several weeks and gradually the pond
should start to hold water

14. Guidelines for pond design and construction (Contd…)
Stocking the fish
• Wait 4-7 days before stocking the fish
• This allows the natural food production in the pond to reach a
sufficient level to sustain fish growth
• In case you decide to introduce substrates in the pond, you will
have to wait longer until the substrates are colonised by
organisms that can be eaten by the fish.
• Stock the young fish (fingerlings) gently
• The temperature of the water the fingerlings come from should be
about the same as the water temperature in the pond
• 2 to 4 fish per m² of pond area are appropriate with a sex ratio of
one male per 4 to 5 females
• The male fish should weigh 200 to 300 grams, the females 700
grams or more

15. 3.4. Aquaculture Management
Fish growth rate and yields from aquaculture enclosures can be
greatly increased through adequate management
This necessarily involves manipulating a complex of interacting
factors
 Biological
 Physical
 Chemical, and environmental
Pond managements includes
• Pond preparation
• Fertilizing
• Liming
• Feeding fish
• Stocking of cultural fish
• water quality maintenance
• Harvesting and marketing and record keeping

16. 3.4. Aquaculture Management (Cont…)
Fertilizing
• The principle of preparation is basically the same for old and new
pond.
• It generally involves lime and fertilizer treatment of pond bottom
water
• To reduce loss by seepage
• Improve pond fertility
• Stimulate plankton production
If liming is necessary the following rates are recommended
• Quicklime/Slaked lime (Cao) --------20-50gm/m2
• Agriculture lime (CaCo3)------------50-200gm/ m2

17. Water quality monitoring and maintenance
The quality of water is one of the significant factors affecting fish
yield.
For the optimum performance of fish species
 Water neither be too acidic or alkaline
 Contain enough dissolved oxygen
 Not be muddy or turbid
 Not to have offensive colour
 Suitable temperature and salinity
 Free from pathogens as well as pollutants
 Interaction between the water, soil, and other organisms changes
these water quality parameters and beyond certain tolerance levels
this imposes stress on the fish population.
 It is therefore very important for the fish farmer to maintain good
quality water desirable for fish culture.

18. Water quality monitoring and maintenance (Cont…)
Message and recommendation to maintain quality water
 Maintains pond water is at green colour (too deep green colour
should be avoided)
 When PH of water is consistently low i.e. acidic condition water
testes sour prevents phytoplankton growth despite fertilization thus,
the pond should be limed
 Avoid or watch out for low dissolved oxygen which is caused by
excessive fertilization, heavy plankton blooms, excessive feeding,
and overcrowding, extended period of cloudy
 During low oxygen fish come to the surface to grasp for air

19. Water quality monitoring and maintenance (Cont…)
 If you happen to see the symptoms of low oxygen immediate
action is needed such as replace with new water, decrease feeding
rate, and pump fresh oxygen
 Maintain water depth at 1-1.5m
 Remove thick black mud frequently from pond bottom because
they contain bacteria which lead to increased BOD

20. Water quality monitoring and maintenance (Cont…)
Toxic substances
 Many chemicals used in animal husbandry and crop production on
non-organic farms are poisonous to fish
 Such chemicals and synthetic medicines should never be used in
proximity of the pond
Feeding fish
 Fish growth and yields are usually much higher with
liming/fertilization and supplementary feed
Supplementary food enables the fish farmer to observe
 Behavior
 Healthy status
 Feeding level
 Size changes during feeding

21. Feeding fish (Contd…)
Supplemental feed is
 Agricultural by-products (e.g. oil cakes, brans) industrial by-
products (e.g. brewers waste)
 Animal by-products (e.g. blood meal), and
 Waste products e.g. chickens droppings.
 Balanced/complete ration are formulated by combinations of
protein, lipids, vitamins, and carbohydrate

22. Feeding fish (Contd…)
Points to be considered during fish feeding
• Feed to maximize your profit
• Use locally availably feed stuffs
• Prepare feed in small quantity
• Package store in sealed container in cool dry place
• Always maintain pond water at green colour
• Feed regularly twice a days at specific time and area
• Avoid over feeding to prevent fouling and pollution

23. Harvesting and Marketing of fish
 Cropping or harvesting is of fish pond is undertaken when fish stock
or part of it has attained market size
 The market size of fish is determined by consumer acceptability and
preference
 Most fish species with proper feeding management reach market
size within 6-9months of stocking or maximum of 12 months
 Harvesting of fish can be started as soon as fish reach table size or
when the water level in the pond is goes below 50cm

 You can always harvest for family consumption or late at one time
for marketing

24. Recording Keeping in Aquaculture
• It is important to keep record of fish farming activities in a note
book
• It helps to achieve the maximum possible rate of fish production
• It records all aspects of fish farm operation and is important to
the fish farmer
Record keeping is important for
• Its aids in evaluating farm profitability
• It provides vital management information

25. Recording Keeping in Aquaculture
Example of record keeping