FISH FARMING

FISH FARMING

1.0. INTRODUCTION.

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- 40,000 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.

• Fish as food

Fish is rich source of protein

The cold liver is vitamin A and D rich

Fish is believed to have less cholesterol than other animal proteins

It’s easy to grow

Are cheap than some kind of meat.

It’s available as food all the year round.

• 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 a few 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.

• Source of income

A farmer can generate additional income through selling surplus fish.

• Employment in fishing industries- both direct and indirect
• Foreign exchange earner
• Recreation–there are certain species of fish that serve the aesthetic values like gold fish in big hotel receptions.
• Research

• Raw materials to industries

Cod liver oil for pharmaceutical industries

• 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 hybridization 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). Fresh water aquaculture dominates fish farming in Kenya and can be divided into:

• Cold water culture involving culture of rainbow trout (Oncorhynchus mykiss) in highland areas and
• Warm water culture involving the culture of Tilapine fishes, the African catfish, common carp and a variety of ornamental fishes in low land regions of the country.

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/her own land.

FACTORS CONSIDERED IN CITING OF FISH POND

• Water availability
• Accessibility to the market
• Ready market for the fish
• Good drainage

     ATTRIBUTES OF A GOOD FISH PONDS

• Presents of dykes
• Inlet at a shallow end and outlet at a deep end
• Gently sloping end
• Proper and good drainage

ROUTINE POND MANAGEMENT

• Check leakage on the walls of the pond, repair immediately
• Filters should be attended to regularly
• Check how fish are responding to feeding to check health status
• Feed the fish depending on stocking density of the pond
• Add fertilization if necessary
• Check the predators e.g. hammer carps, African fish, eagle king fish, pelicans, alligators
•  Check oxygen levels, ph. on daily basis to see whether there is any turbidity

FISH HEALTH MANAGEMENT

“As they say prevention is better than cure”

Fish health is influenced by three factors: environment, stress and pathogens (diseases). To have healthy fish you will need to have enough good food available, enough oxygen in the pond, protect them from predators, avoid too high stocking densities and handle fish well.

Make sure you get feeds and fingerlings from a reliable source and always disinfect your pond with lime to kill anything that could carry diseases.

Health management is more difficult and needs some experience. Always seek advice from expert when abnormalities, signs of pathogens or parasites, are observed.

Common sources of stress for fish include:

        1. Poor nutrition

        2. Poor environmental conditions

        3. Overcrowding in ponds

Signs and symptoms of fish diseases

Diseases can be observed through changes in the fish appearance, behaviour and at an advanced stage: death.

Through observation the followings signs can be seen:

1. Fish jumping out of the water
2. Parasites on the scales/skin of the fish (might need a magnifying glass or microscope). 
3. Large numbers of fish crowding around an inlet of freshwater
4. Loss of appetite by fish
5. Individual fish of unusual colouration—often very dark in appearance
6. Individual fish swimming in circles (“whirling”)
7. Retarded growth
8. Distended stomach
9. Fish flipping on water surface, scraping or jumping
10. External parasites visible on the fins, body, or gills of fish; parasites (worms) visible on/in internal organs
11. Excess mucus on skin
12. Peeling skin, ulcers, lesions, and erosion of fins.
13. Fish deaths increasing over time