Question 4
(a) (i) Explain the term fish pond fertilization.
(ii) State three factors a fish farmer should consider before fertilizing a fish pond.
(b) (i) State three effects of low dissolved oxygen in a fish pond.
(ii) Mention three ways of increasing dissolved oxygen in a fish pond.
(c) Give two reasons why fish pond water should not be drained immediately after feeding the fish.
(d) List three subdivisions of capture fisheries.
(e) State four sources of water to impound a fish pond.
Observation
This question was attempted by few candidates and their performance was generally poor. On fish pond fertilization, the candidates were able to explain the term but could not differentiate between factors to be considered in citing a fish pond.
The expected answer is as follows:
(a) (i) Explanation of fish pond fertilization
It is the addition / application of fertilizer / manure to a fish pond to increase the production of natural food organisms.
(ii) Factors to consider before fertilizing a fish pond
- Type of fertilizer / manure to be applied
- Size of pond
- Type of fish to be reared / raised
- Fertility level of pond
- Quality of fertilizer to be applied
(b) (i) Effect of low dissolved oxygen in a fish pond
- Poor fish growth / stunted growth
- Fish mortality / Fish kills / Death
- Low yield of fish
- Water may have offensive smell
- Poor feed consumption by fish / loss of appetite in fish
- Sluggish movement of fish
- Stress
(ii) Ways of increasing dissolved oxygen in a fish pond
- Use of aerator / aeration
- Pond fertilization
- Splashing of pond water surface
- Flushing / change of pond water
- Placing of ducks on pond water to waddle
(c) Reasons for not draining pond water immediately after feeding fish
- To minimize stress
- To prevent regurgitation
- To avoid economic losses
- To avoid fish kills / mortalities
- To avoid feed wastage
(d) Sub-divisions of capture fisheries
- Subsistence fisheries
- Artisanal fisheries
- ` Industrial fisheries
(e) Sources of water to impound fish ponds
- Surface runoff
- Rivers / streams / spring water
- Wells / boreholes
- Tap water / Municipal water
- Rainfall / precipitation
- Reservoirs / Lakes