CULTURE FISHERY

 

CHAPTER THREE

CULTURE FISHERY

 

Culture fishery is the cultivation of selected species of fish in a confined area in order to get a maximum yield. In other word, it’s the rearing or production of aquatic organisms in a control or confined environment.

3.1       AQUATIC ENVIRONMENT AS HOMES OF FISHES

            There are some water bodies that fish abode which we shall discuss under this heading:

a. LOTIC WATER: These are flowing or moving water, such has creek, brook, river, spring, channel or stream. The water in lotic ecosystem, from source to mouth, must have atmospheric gases, turbidity, longitudinal temperature graduation and material dissolved in it. Lotic ecosystems have main zones, rapids and pools. Rapids are the areas where the water is fast enough to keep the bottom clear of materials, while pools are deeper areas of water where the currents are slower and slit builds up.

b. LENTIC WATER: It entails a body of standing water, ranging from ditches, seep, pond, seasonal pools, basin marshes and lakes. Deeper waters such as lakes, may have layers of ecosystems, influenced by light. Ponds, due to their having more light penetration are able to support a diverse ranges of water plants.

c. FRESHWATER HABITAT: This is a body of water formed mainly from inland water that does not contain salinity. E.g rivers, pond, streams, spring, lakes etc.

d. BRACKISH WATER: This is water that has more salinity that freshwater but not has much as sea water. It may result from mixing of seawater and fresh water, as in estuaries.

e. SEAWATER: These are water that contains salt. They make up the oceans and seas.

3.2       ORGANISMS THAT LIVES AROUND THE AQUATIC ENVIRONMENT

I. PLANKTON: They are very small plants and animals that float on the surface of the sea and on which other sea animals feed.

II. NEKTON: The collection of freshwater and marine organisms that can swim freely and are generally independent of currents ranging in size from microscopic organism to whale. It can be fish, crustaceans, mollusks etc.

III. BENTHOS: These are all plants and animals living in or closely associated with the bottom of a body of water especially the oceans.

 

3.1       COMMON QUALITIES OF CULTURABLE FISH SPECIES

1. High survival rate- The fish must survive in captivity.

2. Acceptance of artificial feed- The fish must be able to accept man-made or compounded feed.

3. Hardiness- The fish must be hardy and able to withstand handling conditions.

4. Breeding under captivity- It must be able to reproduce or induced in artificial environment

5. Compatibility- The fish must be able to partner with other fish species i.e polyculture.

6. Tolerance to poor water condition- Must be able to grow and succeed under poor water condition.

7. Fast growth- It must have good growth and attain market size within a short time.

8. Diseases resistance- It must be able to withstand a wide range of fish diseases.

9. Marketability- The fish must be highly demanded with high price.

10. It must be palatable with high nutritive value.

3.2                   COMMON CULTURABLE FISHERY ORGANISMS

The culturable fishery organisms in Nigeria are: Tilapia, Clarias, Heterobranchus, Carp, Mullet, Snake head and Heterotis.

3.3                               CULTURE FACILITIES

The facilities used in culturing fish are : Earthen pond, Excavated pond, Concrete tank, Plastic tank, Fibre glass tank, Wooden tank and Tarpaulin tank.

ADVANTAGES OF CULTURE FISHERIES

1. Improved food security.

2. Source of income to farmer.

3. Source of employment.

4. Source of revenue to government

5. Better use of wetland.

6. Natural food security is not hampered with increase in population.

7. Large quantities of desired fish are generated.

DISADVANTAGES OF CULTURE FISHERIES

1. Only economically value fishes are cultured.

2. Continuous supply of fresh water is required.

3. Maintenance of natural habitat is desired.

4. Uses of distinct disinfectants are required for diverse variety of fishes. 

STRUCTURE QUESTIONS

1.       Which of the following fish stages is preferable for stocking? (a) Adult (b) Fingerlings (c) Fry (d) Hatchling.

2.       The ratio used in stocking different fish species in a pond is called. (a) Over stocking (b) Stocking density (c) Stocking rate (d) Stocking ratio.

3.       A natural or artificial area used to store water in a fish farm is (a) Pond (b) Reservoir (c) River (d) Stream.

4.       Which of the following describe a lake with good visibility (a) Brackish water (b) Clean water (c) Estaurine (d) Marine water.

5.       The act of putting fish in a pond for the purpose of rearing is called. (a) filling. (b) fixing (c) leading (d) stocking.

6.       A confined body of water where fish are raised under controlled condition is called. (a) lagoon. (b) pond. (c) river (d) stream.

7.       Separation of smaller fish from bigger ones is called (a) cropping. (b) feeding. (c) sorting. (d) stocking.

8.       The total number of fish that is put into the pond is called (a) stocking density (b) stocking number (c) stoking ratio (d) water density.

THEORY

1.       Enumerate five factors to be considered when selecting fish species for stocking.

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2.       Name five culturable fish species.

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3.       List five facilities used in culturing fish.

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4.  Describe each of the following methods of fishing

 (a)Hooking

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 (bTrapping

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 (c) Gill netting.

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5.            State three advantages of culture fisheries.

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