Fish Keeping (Aquaculture)
Introduction
The rearing or keeping of fish is called fish farming and is normally carried out in specially prepared ponds.
A good fish-pond should have the following features:
Site should be on a fairly level ground with a permanent supply or source of water. The area should have clayey soil to avoid loss of water through seepage.
Water must be free from any pollutants such as chemicals and other wastes.
Construction should provide for:
an inlet for fresh supply of water,
a spill way channel to take off overflow or excess water,
an outlet to drain off the water when it is necessary to replace pond water, a fence to keep off predators and other intruders.
Feeding Fish
Fish naturally feed on worms, insects and algae in the ponds.
These sources of food must be supplemented by throwing in the pond ; kitchen wastes,
chopped vegetable materials such as cabbage leaves, cereal brans
brewers' grain .
Management Practices to Ensure Maximum Harvest of Fish
Control of stocking rate, that is to, have the recommended population of fish in a pond at anyone time.
Harvest at the correct maturity stage.
This is done by using the fishing net with correct mesh sizes to avoid catching the fingerlings.
Avoid water pollution in the ponds which may poison fish.
Ensure adequate supply of food in the pond.
Water in the ponds should be kept in motion to facilitate aeration. Maintain appropriate depth (level) of water.
Control predators and/or thieves.
Drain and refill ponds with fresh water as necessary.
Harvesting Fish
Harvesting or extracting fish from the fish ponds for consumption
Two main methods:
Hook-and-line method:
- This is slow, injures small fish and is inefficient.
- It is only suitable for small-scale fishing.
Use of fishing nets:
- This is the most efficient method as long as a net with the correct mesh sizes is used.
- Harvesting may be done 6-8 months after the introduction of fingerlings into the fish pond.
Maintenance of the Fish Pond
Repairing the dyke or any structure on it.
Cleaning the pond and removing foreign materials.
Planting grass where necessary.
Removing un desirable vegetation.
Removing the silt.
Fish Preservation
Practices before preservation:
Clean the fish to remove mud and any worms. Removing scales and slime.
Opening the fish on the side to remove the gut and the intestines referred to as
gutting. .
Cleaning the abdominal cavity thoroughly.
Keeping fish in open containers.
Methods of Preservation
Freezing
Salting
Sun drying
Smoking
Appropriate Handling of Livestock During Management
Physical beating should be avoided.
Structures which help in restraining animals should be used whenever applicable. The correct methods of securing and casting animals should be used.
Use as little force as possible.
Equipment such as ropes, halters, lead stick and bull rings are used to handle animals appropriately.