Observation

This question was attempted by majority of the candidates and their performance was good. The candidates understood the concept of induced breeding and the responses of some showed that they had done the practical aspects. In Question 1(e), many candidates lost vital marks due to errors in the answers provided. Most candidates stated aspects of water quality instead of mentioning the factors that could affect the growth rate of fish in a pond.

The expected answers are as follows: 

(a)        Precautions that should be taken when transporting broodstock

-           Fish should not be fed before transportation
-           Change water during transportation
-           Maintain water temperature during transportation by adding ice to the water
-           Aerate water during transportation
-           Transport at low stocking density
-           Transport during the cool hours of the day (morning or evening)
-           Use fast means of transport

(b)        Reasons for acclimatizing transported broodstock before inducement

-           It allows the broodstock to adjust to the new temperature/environment
-           To reduce stress/shock
-           To reduce mortality
-           To minimise spawning failure

(c)        Activities involved in induced breeding of Clarias

-           Selection                                 -           Inducement/injection with hormones
-           Milt removal                           -           Stripping
-           Fertilization                             -           Incubation
-           Nursing of hatchlings              -           Water quality management
-           Feeding                                   -           Conditioning/acclimatization

(d)       Fish nursery management practices

-           Separate dead and unhatched eggs
-           Maintaining optimum water conditions
-           Hatchlings must be transferred to nursery tanks at 21days/3weeks
-           Shooters or jumpers should be sorted and separated
-           Introduction of artificial feed based on size of the fish/regular feeding
-           Aeration of nursery pond
-           Maintaining clean environment

(e)        Factors that could affect the growth rate of fish in a pond

-           Stocking density                                 -           Quality of feed
-           Quantity of feed                                  -           Age of fish/size of fish
-           Genetic makeup/gene                          -           Sex of fish
-           Water quality parameters                    -           Diseases
-           Pests