Observation

 

This question was well attempted, but the candidates’ performance was below average.
In part (a), majority of the candidates were able to name the materials used in liming fish ponds. However, they could not name the factors that affect fish growth, and they could not describe a fish pond.

In part (b), majority of the candidates did not understand fish pond construction and the various steps involved in constructing a fish pond.

The expected answers include:

(a) (i) Fish pond liming materials
- Calcium carbonate (CaCO3)/agricultural lime/lime stone
- Calcium oxide (CaO)/quick lime
- Calcium hydroxide Ca(OH)2/hydrated lime
- Wood ash
- Oyster shells/periwinkle

(ii)Effect of over fertilization
- It causes pollution of the water
- It causes stress to fish
- It results in fish kill
- Bad water odour could occur
- It causes oxygen depletion in water
- There is algae bloom/high water turbility/low transparency
- It imparts off flavour of fish
- It reduces fish production/yield

(iii)Factors affecting fish growth
- High/low water temperature
- Availability of sufficient/insufficient food
- Stocking density of the fish pond
- Competition among fishes in the fish pond
- High/low dissolved oxygen
- High/low water pH
- High/low nutrients
- Quality of feed available
- Quantity of feed supplied
- Size of fish at stocking
- Polluted water reduces fish growth

(iv)Description of a fish pond
A fish pond is described as an enclosure of water body specifically for growing fish or other aquatic animals under controlled conditions/environment. It has an inlet and outlet.

(b) Activities carried out in each of the following steps during fish pond construction

(i)Activities carried out in each of the following steps during fish pond construction
- Topography survey
- Soil testing/Identifying if there are stones/soil type
- Sourcing for water
- Looking for natural drainage pattern
- Identify types of vegetation

(ii)Staking
- Sharpen stakes to make pegs
- Pegs are used to mark out dimension
- Ropes are used to mark perimeter delineated by p

(ii)Stripping of top soil
- Top soil is removed from pond area
- Top soil is put aside/stockpiled

(iv)Dyke construction
- The soil is excavated from the marked pond area
- Excavated soil is spread in thin layers on the area marked as dyke
- The laid soil is compacted on the dyke area
- The top soil is spread on the dyke after construction
- Suitable grasses are planted on the dyke