Fish and Aquaponics Farming

Fish and Aquaponics Farming Introduction

Did you know that you can produce food through fish and aquaponics farming? Aquaponics refers to any system that combines conventional aquaculture (raising aquatic animals such as snails, fish, crayfish or prawns in tanks) with hydroponics (cultivating plants in water) in a symbiotic environment. In normal aquaculture, excretions from the animals being raised can accumulate in the water, increasing toxicity.

Aquaponics farming started in Asia, when a rice grower found that the rice in the paddies grew better when fish were swimming in them soon after the fields were flooded. The waste from the fish gave a nutrient boost to the rice. An aquaponic system is an environmentally friendly yet an economically viable establishment if intensively undertaken.

In an aquaponic system, water from an aquaculture system is fed to a hydroponic system where the by-products are broken down by nitrifying bacteria into nitrates that are utilised by the plants as nutrients. The water is recirculated back to the aquaculture system. Aquaculture enterprises range from small fish cages owned and run by a farming or fishing family to supplement their diet and income, to several hundred hectares of fish or shrimp ponds owned by large companies and run by hired workers.

Suitable plants for an aquaponic system include cabbage, lettuce, spinach, tomatoes, cucumbers, pepper, red salad onions, okra and snow pea. Tilapia is the most commercially farmed fish species.

Other species include barramundi, silver perch, eel-tailed catfish or tandanus catfish, Jade Perch, Murray Cod, Channel Catfish, Rainbow Trout, Perch, Common Carp, Largemouth Bass and Stripped Bass.

Marketing can be on a “farm-gate” basis, with the buyer picking up freshly harvested fish, or can involve processing, cold storage, and eventual shipment of the product overseas. Therefore, in this chapter, you will Learn about rearing and marketing fish profitably.

Terminology Relating to Fish and Aquaponics Farming

Have you ever seen fish and aquaponics farming in your community? Fish and aquaponic farming is a new agricultural enterprise in Uganda. It is a complex farming system involving a variety of living materials such as aquatic animals, plants and bacteria and the physical structures that provide the habitat or growing medium. In Activity 3.2.1, research and explore the meanings of the terminologies used in fish and aquaponics farming.

Activity 3.2.1 Researching and exploring the terminology used in fish and aquaponics farming

What you need:

Picture cards, notebooks, pen

What to do:

1. In groups, you will receive set A and set B of picture cards. Set A will conatin terminologies and Set B their meanings as used in fish and aquaponics farming.

2. Match the items correctly by identifying a terminology in Set A that matches the meaning in set B.

3. Research and discuss other terminologies used in fish and aquaponics farming and their meanings. Write a full list of the terminologies in your notebook.

Importance of fish

Fish is a high-protein, low-fat food that provides a range of health benefits. White-fleshed fish, in particular, is lower in fat than any other source of animal protein, while oily fish are high in omega-3 fatty acids, or the “good” fats. Since the human body cannot make significant amounts of these essential nutrients, fish are an important part of the diet. Also, fish are low in the ‘bad’ fats commonly found in red meat called omega-6 fatty acids. Using Figure 3.2.1 and Activity 3.2.1, explore the value of fish in nutritional and commercial terms.

Activity 3.2.2 Acting a dialogue on the importance of fish

What you need:

Fish, money, notebook, pen

What to do:

1. In pairs, act the following dialogue between Ashaba (client) and Oketch (fish farmer) on the importance of fish.

Oketch: Hello, Ms. Ashaba. Nice meeting you once again.

Ashaba: Thanks. Is your fish farm doing well, Oketch?

Oketch: It is progressing. You did not come for more fish. What happened?

Ashaba: Do you know that I have a prescription of fish as part of my daily meals? That is the order from my nutritionist.

Oketch: I told you fish should be a regular part of your daily meals. Do you know that the nutrient content of fish helps to control cancer, asthma, cardiovascular disease?

Ashaba: My friend, I am on a daily dose. Good enough, my children can eat fish but not any other meat.

Oketch: You can also start a fish farming project of tilapia, carp of trout at your home. It will give you steady supply of fish for food and income. When your project exponds, you can export the fish and get foreign exchange.

Ashaba: Thanks Oketch. I will adhere to your advice. Meanwhile, give me three kilograms of tilapia. What is the cost?

Oketch: A kilogram is just at UGX 15,000. treceives the money! Thank you Ashaba.

Ashaba: [receives the fish] Thank you Oketch. Good time!

Oketch: Bye!

2. Answer the following questions using the information provided in the dialogue.

a) According to the dialogue, how is fish important in human nutrition?

b) Identify the diseases and disorders that can be controlled through fish consumption.

c) Examine the different ways fish acts as commercial product in Uganda.

d) Discuss how fish farming earns foreign exchange to the farmer.

e) According to the dialogue, which fish species can you rear in a fish.

pond at your home?

3. Record your findings in the notebook and discuss them with peers.

Selection of appropriate fish for rearing

For all agricultural enterprises, a farmer is required to select breeding materials. There are a number of fish species that suit the fish and aquaponics farming system. The farmer needs to establish what species of fish work best for his or her system. In Uganda, the most commonly grown fish are Tilapia, Trout and carp. However, other species such as Mud fish, Catfish, Nile Perch can equally do well in fish ponds, cages or tanks. What species of fish do farmers in your communities rear? Using Figure 3.2.2 and Activity 3.2.3, select appropriate fish species reared in Uganda.

Activity 3.2.3 Selecting fish for rearing

What you need:

Notebook, pen, camera, Internet

What to do:

1. In groups, visit a fish farmer near your school. You may watch a video or observe photographs on fish species reared in cages, tanks or ponds. 2. Observe and note the species of fish he or she rears.

3. Ask the farmer to tell you the benefits and challenges associated with the fish species he or she farms. 4. Inquire from the farmer what other fish species he or she has reared or knows about.

5. Get information from the Internet or textbooks on the advantages and disadvantages of each fish species.

6. Share with the farmer the various biological and economic factors he or she considered to select the fish he or she rears.

7. Record findings on the factors as follows: a) Biological factors

i) Growth rate

ii) Feed conversion efficiency

iv) Resistance to diseases

v) Productivity or yield

vi) Salt tolerance

iii) Tolerance to fluctuations of environmental factors

b) Economic factors

i) Cost of production

ii) Availability of fish seed and feed

iii) Marketability

8. Examine and note the fish feeds. Ask the farmer about their availability, nutrient composition and cost.

9. Discuss the climatic conditions of the area, and their influence on production of the fish species.

10. Ask the farmer to tell you what qualities buyers look for when purchasing fish.

11. Draw the shape of the fish that the farmer is rearing and compare it with other fish species that you know. Record your findings.

12. What is your comment on the selection of fish that the farmer is rearing?

13. Brainstorm the qualities that will make you a successful fish farmer. Record the qualities in your notebook.

14. Use the findings of the study to select appropriate fish species for rearing.

Assessment of Soil Suitability for Fish Pond Construction

A pond is a water enclosure or a confined body of water where fish are raised or reared under a manageable controlled condition. A pond could either be earthen, concrete, plastic or fibre. Nowadays fish are raised in plastics, fibre tanks and wooden rafts which are either locally fabricated or imported from developed countries.

A fish pond cannot be constructed in any type of soil. There is therefore a need to establish the soil texture, and conduct drainage, ground water and soil permeability tests to ensure the soil is fit for a fish pond construction. Why do you think you need to assess each of the soil characteristics for pond construction? Use Activity 3.2.4 to assess soil suitability for fish pond construction.

Activity 3.2.4 a) Determining soil texture suitability for fish pond construction

What you need:

Soil auger, water, notebook, pen, instructor, farm tools

What to do:

1. In groups, clear the vegetation on the surface of the site.

2. Remove the top soil cover with organic matter.

3. Get a sample of sub soil on your hand and wet it with a little amount of water.

4. Close the soil sample in your hand firmly. Open the hand and observe the shape formed. Record your observations.

5. What conclusion do you make of the soil suitability for construction of a fish pond? Check your findings against those presented in the following table.

Activity 3.2.4 b) Determining ground water suitability for fish pond construction

What you need:

Hoe, spade, water, notebook, pen

What to do:

1. In groups, dig a pit of 1m depth on the site and cover it with leaves for a night.

2. Observe the content of the pit in the morning of the next day.

3. Basing on your findings, what conclusion can you make on soil suitability for construction of a fish pond?

4. If the pit is empty the next morning, carry out the water permeability test. Check your findings against those presented in the following table.

Activity 3.2.4 c) Determining soil permeability for fish pond construction

What you need:

Hoe, spade, water, notebook, pen

What to do:

1. In groups, fill the pit with water and cover it with banana leaves. 2. Remove the leaves from the pit in the morning of the following day. What do you observe.

3. Write your conclusion on soil suitability for pond construction if no water is found in the pit in the morning of the next day.

4. Repeat steps 1 and 2 if no water is found in the pit in the morning of the next day.

5. Write your conclusion on soil suitability for pond construction if water is found in the pit in the morning of the next day.

6. Check your findings against those presented in the following table.

Construction of Fish Ponds

Before you assess the soil suitability for fish pond construction, ensure the site itself is suitable. The site chosen should be flat, large enough and not prone to flooding. Did you know that when ponds flood your fish will escape? Where possible, the site should be slightly lower than the water source to allow water flow into the pond by gravity. What other qualities will you desire a site for a fish pond to have? Also, mind about the ease of access to the site by a vehicle to ease transport of inputs and harvested fish. In addition, a safe and secure environment is desirable. How can you ensure safety and security of your fish pond? Use Figure 3.2.3 and Activity 3.2.5 to construct a fish pond.

Activity 3.2.5 a) Constructing a fish pond

What you need:

Hoe, spade, notebook, pen

What to do:

1. In groups, prepare the site by removing unwanted things such as the trees, bushes, and rock.

2. Construct a seepage-free and secure barrier or bank using clay.

3. Dig a desirable size of a pond and construct a dyke over the clay core. The pond size should be 1-1.5 m deep for a nursery pond, 1.5-2 m for a rearing pond and 2.5-3 m for a stocking pond.

4. Cover the pond dyke with soil and plant grass species like paspalum. How is paspalum useful on the dyke? Why should trees be avoided on the dyke?

5. Fence the pond to avoid theft and entry of predatory animals. Write down the examples of predators of fish that you know.

6. Plant tobacco around the pond to keep off snakes as they predate on fish.

7. Practise fish pond construction for fish and aquaponics farming at your school. Record your activities.

8. Does your pond meet the standards of a typical fish pond? Assess its standard using the following table and adjust accordingly.

Activity 3.2.5 b) Constructing an inlet for a fish pond

What you need:

Hoe, spade, pipe, notebook, pen

What to do:

1. In groups, make a gap on the barrier or bank that is nearest to the source of water of your inlet pipe.

2. Put the inlet pipe (10 cm diameter for small ponds and 20 cm for big ponds) at a height above the water level in the pond (about 1.10 m from the pond bottom). What materials can we get a pipe from?

3. Place the inlet pipe slightly below the level of water source.

4. Fill the gap cut in the dam or dyke after placing the pipe properly.

5. Put a screen on the entrance of the pipe to prevent wild fish or debris from entering your pond. From what materials can you make a screen?

6. Practise construction of a fish pond outlet and drainage for a fish and aquaponics farm at your school. Record findings in your notebook.

Activity 3.2.5 c) Constructing an outlet and drainage for a fish pond

What you need:

Hoe, spade, pipes, notebook, pen

What to do:

1. In groups, dig a gap in the wall at the deeper end of the pond to act as an overflow drain. The gap should touch the bottom of the pond.

2. Insert the pipe which should stretch from the deepest part on the inside of the pond through the dam or dyke to the outside of the pond to drain water.

3. Position a screened pipe outlet in the space between the water level and the top of the dam. Why should the pipe have a screen?

4. Practise construction of a fish pond inlet for a fish and aquaponics farm at your school. Record findings in your notebook.

Stocking and Managing a Fish Pond

What will be the next step after your pond is well constructed? How are you going to stock the pond and manage the fish? Did you know that fish stocking is the practice of raising fish in a hatchery and releasing them into a pond, river or lake to supplement existing populations or to create a population where none exists. Stocking a fish pond means introducing fish fingerlings into the pond. A fish farmer should understand the principles governing fish pond stocking and management. Before stocking your pond, carry out a water transparency test using a secchi disc. Use Figure 3.2.4 and Activity 3.2.6 to explore the principles of fish rearing in ponds.

Activity 3.2.6 a) Performing an impromptu speech on stocking and managing a fish pond

What you need:

Notebook, pen, sentence slips

What to do:

1. Individually, you are invited in front of an audience to deliver an impromptu speech on the principles of rearing fish in ponds.

2. Read the statement once as the audience write. The audience should check if they have written the same statement.

3. Guide the reader to discuss the principle with the audience.

4. Discuss with your peers other principles they will consider for their fish pond project.

5. Practise the principles of stocking and managing fish on their fish ponds. Share experiences with peers and record findings in your notebook.

Activity 3.2.6 b) Measuring water transparency using a secchi disc

What you need:

Notebook, pen, sentence slips

What to do:

1. In groups, take Secchi readings at about mid-day when there is no shadow. If not possible, take readings at about the same time every day.

2. Position yourself such that there is a very little amount of shadow falling off from you to the Secchi disc.

3. Hold the rope or board where the secchi disc is suspended upright and release the disc into water. So that it is lying flat.

4. Slowly, lower the disc into the water to the point where it starts becoming invisible and you cannot clearly see it. Read the measurement on the rope.

5. Slowly, raise the disc out of the water until it starts to become visible. Measure this depth.

6. Calculate the average of the two readings. This will give the secchi depth.

7. Look at the reference colour chart to assess the level of turbidity. Check your findings against those presented in the following table.

Diseases, Parasites and Predators of Fish

Fish are affected by a number of diseases, parasites and predators that affect their productivity. Fish diseases and parasites reduce the production potential of fish in terms of growth and weight gain. Predators hunt, kill and eat fish hence reducing their numbers. Use Figure 3.2.5 and Activity 3.2.7 to identify and control diseases, parasites and predators in fish.

Activity 3.2.7 Identifying and controlling fish diseases, parasites and predators

What you need:

Veterinarian or fish farmer, video clip on fish diseases, parasites and predators, fish with observable disease symptoms, notebook, pen

What to do:

1. In groups, you will receive three different pieces of fish or photographs or video clips on infected fish to examine.

2. Identify and record the disease symptoms exhibited by each fish provided. 3. State what might be the cause of the condition exhibited by fish you have examined.

4. Look for information on fish diseases from the Internet, books, journals or brochures. such diseases should include:

a) columnaris disease

b) streptococcus infection c) fish tuberculosis

d) epizootic ulcerative syndrome

e) tilapia lake virus

f) koi herpes virus (KHV) disease

g) escoid lymphosarcoma

h) pseudomonas flourescens

5. Discuss how a fish farmer can minimise the condition in fish.

6. Ask the veterinarian or model fish farmer about fish diseases, parasites and predators.

7. Ask them how to control diseases, parasites and predators in fish.

8. Practise the control measures for fish diseases, parasites and predators. 9. Submit a report to the teacher for guidance. You can use Microsoft word to write the report.

Harvesting or Cropping of Fish

The process of harvesting mature fish is called fish cropping. Cropping fish should be done when the fingerlings have developed to a marketable size depending on fish species. There are many methods of harvesting fish using a variety of tools and equipment.

Trawling, purse seining, gill net, hook and line mechanised, jigging and trolling lines are the common methods of cropping fish. Which of the methods of cropping fish have you ever seen or used? Name other methods of fish cropping that you know. A method to use in harvesting may be dependent on skill, size of the pond and size of the fish. What methods of harvesting fish have you ever seen? Use Activity 3.2.8 to guide you on harvesting fish in a pond.

Activity 3.2.8 Harvesting fish from a pond

What you need:

Camera, notebook, pen

What to do:

1. In groups, visit a fish farmer near your school. Alternatively, you can watch a video or observe photographs on fish cropping or harvesting.

2. Identify the different methods and equipment used in harvesting fish.

3. Discuss the factors that determine the equipment to use during fish harvesting.

4. Observe and record a demonstration on fish harvesting practices in ponds.

5. Inquire about the guidelines for successful commercial fish rearing. Note the guidelines in your notebook.

6. Practise harvesting fish from your fish production project.

7. Write an article in your school magazine on guidelines for successful commercial fish farming.