(a) Describe the construction of a fish pond (b) State eight measures necessary for the efficient operation of an egg incubator.

(a) Construction of a fish pond

A good site with a gentle slope, near a reliable source of clean water and on soil that holds water (clayey/loamy) is selected. The area is cleared of bush, stumps and debris and the outline of the pond is marked out. The topsoil is removed and the pond is dug to the required depth (deeper at one end so that it can be drained). An embankment (dyke) is built round the pond and compacted so that it is firm and does not leak. A water inlet (pipe or channel) is provided to let water in and an outlet/monk with a screen is provided to control the water level and to drain the pond; the screens keep fish in and predators out. The pond bottom and dykes are made watertight (a clay lining or concrete may be used), the pond is limed and manured to encourage the growth of natural fish food, then it is filled with water and stocked with fingerlings.

(b) Eight measures for efficient operation of an egg incubator

• Select and set only fertile, clean, medium-sized and well-shaped eggs.
• Maintain the correct incubation temperature (about 37.5 to 39°C / 100°F).
• Maintain the correct humidity in the incubator to prevent the eggs from drying up.
• Turn the eggs regularly (several times a day) to prevent the embryo from sticking to the shell.
• Provide adequate ventilation so that fresh air (oxygen) reaches the eggs and carbon dioxide is removed.
• Candle the eggs to detect and remove infertile or dead-in-shell eggs.
• Keep the incubator clean and disinfected to prevent disease.
• Ensure a steady, uninterrupted source of power/heat and check the thermostat and thermometer regularly for accuracy.