Observation

 

This question was well attempted by the candidates, and their performance was good.
In part (a), majority of the candidates were able to list the parameters of water quality that affect fishes in a pond.

In part (b), majority of the candidates named the conditions that could reduce the level of dissolved oxygen in a fish pond.

In part (c), majority of the candidates could not differentiate between general management practice and daily management practice.

In part (d), majority of the candidates were able to list five items used in constructing a seine net.

The expected answers include:

(a) (i) Water quality parameters
- Temperature
- pH
- dissolved oxygen
- nutrient availability
- conductivity
- turbidity/transparency
- hardness
- alkalinity
- ammoia/nitrite

(b)Conditions that reduce the level of oxygen in fish ponds
- overfeeding
- presence of zooplankton
- high stocking density/overstocking/overcrowding
- reduced phytoplankton population/high transparency in water
- long period of hot weather
- oxidatio process of decay
- high temperature
- high load of organic matter
- over fertilisation

(c) Daily management practices in a fish pond
- maintenance of water level
- check leakages
- clean filters
- observe fish behaviour/culling of injured, weak or deformed fish
- feed the fish
- watch out for predators
- monitor water quality parameters
- removal of dead fish

(d)Materials for making a seine net
- rope
- float/cork
- sinkers/lead/weight
- netting
- twine/string
- knife
- mending needle