Question 3
(a) (i) Describe how specimen K is used in capture fisheries.
(ii) Which of the specimens R and S is preferred for fish pond construction?
(iii) Give three reasons for the answer given in 3(a)(ii).
(b) (i) State three effects of specimen L in a fish pond after fishing activities.
(ii) Mention two ways in which specimen L could be controlled in a fish pond.
(c) (i) State one use of specimen M in fisheries.
(ii) State one factor to be considered when using specimen M in fisheries.
Observation
Most candidates could not state correctly the specimen preferred for fish pond construction. Many candidates could not differentiate between specimen L (a toad) and a Frog. As such, it was difficult for them to highlight the negative consequences of having the animal in ponds and how it could be controlled.
The expected answers are as follows:
- (i) How specimen K (Purse seine net) is used in capture fisheries
- Attach specimen K to a boat/ fishing vessel
- Lower the specimen into the water from the vessel
- Let it hang in the water with the help of the floats and lead/ weight
- Encircle the school of fish
- Haul the bottom line to close the bottom to form a bag
- Gradually move the net into the vessel or craft
- Fish are scooped out / retrieved
(ii) Preferred specimen for pond construction
- Specimen R (Clayey soil)
(iii) Reasons for preference
- Can hold water/ retains water / high capillarity
- Does not drain water easily
- Stability of dyke / withstand some level of erosion of pond embankment
- Compacts better / sticky when moist / wet
- Can withstand water pressure
- (i) Effects of specimen L (Frog) in a fish pond
- Predates / Preys on fish/ eats fish / eats fish eggs
- Competes with fish for dissolved oxygen
- Competes with fish for space
- Competes with fish for food
- Contaminates pond water
- Transmits diseases / pathogens to fish
(ii) Control of specimen L (Frog) in a fish pond
- Lime the pond
- Net the pond / fencing
- Clear the pond of weeds/ good sanitation
- Use of baited traps
(c) (i) Use of specimen M (Needle and Syringe) in fisheries
- To administer hormones
- To obtain blood samples
- To inject vaccines / medications
- To administer anaesthetics to fish
(ii) Factor to consider when using specimen M (Needle and Syringe) in fisheries
- Size of fish / age
- Proper handling and disposal of needle and syringe
- Muscle building in fish /musculature of fish
- Type of vaccine to administered