CULTURE SYSTEM

CHAPTER SIX

CULTURE SYSTEM

 

FISH CULTURE

Fish culture is concerned with breeding fish to increase and improve fish stock. It includes the raising of fish in natural bodies of water and in artificial ponds.

6.1                                       TYPES OF FISH CULTURE

1.         POLYCULTURE: As the name implies is the culture of several species in the same water body. The cultures system generally depends on natural food of a water body sometime augment artificially by fertilization e.g polyculture of clarias  gariepinus (catfish) and tilapias in Africa.

2.         MONOCULTURE : as the name implies, is the rearing of a single species of organisms in a culture system of any intensity in any type of water e.g tilapia catfish etc.

3.         MONOSEX CULTURE: This is based on the culture of fish by producing all males or all females depending upon the sex which have better food conversion rate and growth rate. For example we can say that the male tilapia grows faster than female, then the culture of male is beneficial in case of tilapia (hybridization method)

4.         MIX-SEX CULTURE: This is based on the culture of fish by producing males and female. For example in a mixed-sex tilapia culture, the fish is normally harvested before the fish reaches sexually maturity or soon after wards.

5.         FIN-FISH CULTURE: This is concerned with the culture of producing fishes having fin it is also termed as pisciculture

6.         SHELL-FISH CULTURE : This is based on the culture of fish by producing shell fish such as molluscans, crabs, prawn etc

7.         FRESH-WATER CULTURE: This is based on the culture of using fresh water bodies like river, stream, lakes and pond in producing fish.

                                           

 

 

 

 

6.2                                                   CULTURE SYSTEM.

 

1.     POND (EARTH AND CONCRETE): Pond culture are the most common aquaculture production system. Pond system may be either earthen or concrete, the most common one is an earthen pond which is created by earth levees although other materials can be used. The size of pond varies depending upon its purpose. Some pond do not have the water inflow or a drain.

2.     CAGE CULTURE: This culture involves growing the aquatic organism within cages. The cages can be placed in any water source as long as an adequate flow of water is maintained through the cage. One disadvantage of cage culture is that they are susceptible to biological pollution where the non-native species being culture escapes and disrupts the local system e.g catfish, carp, etc.

3.     TANK CULTURE: The tank can be constructed of cement, fiberglass, or any other durable material. Tank culture is more sophisticated and productive than either pond or cage but they are more expensive. This is because the tanks are constructed so that there is a continual flow of water through the system.

4.     TUBE CULTURE: This is used in rearing oyster’s larvae which are allowed to set along length of plastic tubing or rope where the seed then naturally attaches itself to the surface. The tubing or rope is then vertically suspended from a secured flotation device in deep subtidal water. 

5.     RAFT CULTRURE: Oysters are placed in trays which are then suspended from a secured flotation device in deep subtidal water

6.     PEN CULTURE: Is the system of culturing fish within a fixed net enclosure either at the bank or in a water body. The bed of the water body service as the bottom of the pen. E.g tilapia

7.     RACEWAY CULTURE: This is a method by which flowing water is diverted from natural stream or well. Raceway is typically used for raising rainbow trout. To be considered a low-risk method, waste must be treated and fish escape prevented.

  STRUCTURE QUESTIONS

1.            The culture system mostly practiced by fish farmer in Nigeria is (a) Extensive (b)Inclusive (c) Intensive (d) Semi extensive (e) semi intensive

2.            A fish system with high level of controls over its management is (a) extensive (b) inclusive (c) intensive (d) semi extensive (e) semi intensive

3.            The following are advantage of polyculture in fish farming except (a) fish are more resistance to disease (b) natural foods in the pond are better used (c) under stocking of fish is encouraged (d) fish of any size or cage can be raised (e) overpopulation ponds can be controlled.

4.            A typically concrete pond should have (a)automation feeder (b) its top covered with nets (c) organic matters (d) inlet and outlet pipes (e) different species of fish

5.            Which of the following stages in fishery is stocking of pond carried out? (a) egg (b) larva (c)fingerling (d) adult (e) cyst

6.            How many fingerling catfish can you stock in a 40Ft2 cage (a) 250 (b)475 (c) 350 (d)600

7.            Netting for fish cages can be made of what? (a) plastic (b) wire (c) polyethers (d) A and C (e) all of the above

8.            Where do ponds come from? (a) they occur naturally through erosion (b) city engineers dig them to collect rain water (c) they are dug by ranchers to store water (d) all to the above

9.            The practice of fish producing all males or all female refers to (a) monoculture (b) shell culture (c) mono-sex culture (d) none of the above

10.          Fish culture is concerned mainly on fish to increase and improve fish stocks. (a) breeding (b) stocking (c) fertilizing (d) incubating.

11.          The following are fish culturing media except (a) Aquarium (b) Cage (c) Silo (d) Pond.

12.          The act of rearing only one species of fish in a pond is called (a) Aquariculture (b) Mariculture    (c)Monoculture (d) Polyculture.

13.          The culturing of different species in a pond at a time is (a) Intensive culture (b) Mix-sex culture (c) mono-sex culture (d) Polyculture.

14.          Which of  the following is not required for pond preparation (a) Cutlass (b) Spear (c) Spade (d) Digger.

15.          The culture system which depends on natural and supplementary food materials is (a) Extensive (b) Integrated (c) Monoculture (d) Polyculture.

16.          Culture system which depends mainly on natural food is called (a) Extensive (b) Intensive (c) Integrated (d) Monoculture.

                                                                         

THEORY

1.          Explain any 3 types of fish culture

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2.      Explain the following  culture system

(i) pen culture

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(ii) pond culture

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 (iii) raceway culture.

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3.      Give 2 advantages and 2 disadvantages of

 (a) poly culture

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  (b) cage culture.

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4.      Give four examples of integrated fish farming.

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