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)

                                                                   N487, 200.00

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

                                                           N87, 800.00 (total gain for the first

Production)