This question was poorly attempted by the candidates. In 1(a)(i – ii), majority of the candidates could neither identify specimens A(Tilapia) and B(Clarias) correctly, nor mention the observable features of specimen A(Tilapia).
However, in 1(b), majority of the candidates were able to state the characteristics of specimen B (Clarias) that make it culturable. But in 1(c), most of the candidates were unable to mention the common natural foods that specimen B (Clarias) feeds on in a fish pond.
The expected answers include:
1(a)(i) Identification of Specimens
A – Tilapia/Tilapia sp
B – Clarias/Clarias gariepinus/African catfish
(ii) Observable features of Specimen A (Tilapia)
- Presence of mouth
- Presence of scales on the body
- Presence of visible/discontinuous lateral line/lateral line is broken into two sections/divided into upper and lower sections
- Presence of spine on the fin/many spines
- Presence of single pair of nostrils/only one nostril on each side
- Body shape is laterally compressed/flattened
- Presence of eyes
- Presence of operculum/gill cover
- Presence of peduncle
(c) Common natural food for Specimen B (Clarias) in the Pond
- Earthworm/worms - Aquatic weed/macrophytes/plant/benthic plant
- Mosquito larvae/zoo plankton - Young fishes
- Tadpoles - Phytoplankton/algae
- Aquatic weeds - Detritus
- Eggs of insects |