FISH FARMING AND POND WATER QUALITY
By Zachariy Winam. Fish Farming Extension Officer at Ministry of Agriculture, Livestock and Fisheries Kenya.
Increase Pond Productivity
It is true that fish prices have doubled over the past two years. The consumption of fish is also increasingly becoming popular with non lake region community. The population around the lake has also increased making the demand for fish also to increase. This has resulted to the increase in pressure on Lake Victoria hence a need to find alternative source of fish through fish farming.
For farmers to get profit from fish farming there are five founder mental things that a farmers should do
• Proper planning
- Water quality check
- Fish sampling
- Marketing and value addition
This is where the success begins and failure is noted. Many farmers do not have a farm plan. Farm planning is very important because it can help one secure a loan to finance their farming. Farm planning shows long term and short term strategies. Farming as a business requires one to know their strengths, weakness, opportunities, and threats.
From my own experience in fish farming it is proper to consider the type of pond one wants to use for fish farming. The types include earthen ponds, liners ponds, or cemented ponds. But note that earth pond is cheap as compared to liner pond and cemented pond. For earth pond one requires soil that can hold water. This is mostly found in wetland areas where nothing can grow and the land is lying idle. One needs to consider land topography which will help avoid any floods.
In the farm plan one should include the following
- Pond disinfection
- Liming of pond
- Stocking and sampling
- Harvesting, sales, marketing and value addition.
Water Quality Check
It is important to note that fish does not live in the soil but water. Inside water is where fish feeds, breaths, excrete wastes, reproduce, take in and lose salt. Poor water quality will definitely affect the growth of the fish. Such fish will suffer from stunted growth. Most farmers do complain that their fish is not growing. That could be as a result of poor water quality. To great extent water quality determines the success or failure of fish farming. In water quality check, one needs to measure the temperature, ammonium level, water PH, and Oxygen percentage in water. These are very important tests that a farmer needs to carry out during the production period.
Currently the equipments for measuring water quality are expensive for small scale farmers. However, farmers can use simple observation and knowledge to maintain water quality. There are very many sources of water with different qualities. For example, wells and springs are a good source of water for fish farming. Wells usually have constant temperature and are usually free from wild fish and insects. However, wells will require pumping and this is expensive, and may generally have low levels of carbon dioxide. Springs are good source of water for fish farming and most earth ponds are located near spring areas. These are found in wet land areas and require no pumping cost. Springs have relatively stable temperature, but flow rate may vary with season and insects or fish may inhabit. Please not that one needs to protect spring water area by planting water friendly trees that can sustain water availability throughout the season. Another source of water is municipal water which is of high quality. However, it has chlorine or chloramine present and is expensive. Roof catchment and runoff can also be a good source of water, particularly for liner ponds. Rain water is free and can be harvested and used in fish farming. This method can be used in high or low rainfall areas where the annual rainfall is above 1500ml or below. Runoff needs to settle down before directed to the pond. One can dig a reservoir where water collects and settles before directed to the pond.
Note that too much siltation from runoff may block the gills of the fish resulting into their death. Stream, rivers and lakes are also good source of water for fish farming and large quantities may be available. However, temperature varies widely. Excess nutrients may also be present and is also a home of unwanted fish and insects making the quality to be questionable.
Monitoring of water quality is a very important aspect that farmers should look into. Most farmers just feed their fish without knowing the oxygen level in the water hence resulting into wastage of food and money. When the fish are suffering from luck of oxygen, they will not feed resulting into malting of feeds. This affects the water quality and could raise ammonium level which is very poisonous to fish.
The smell of the water should indicate to one weather the ammonium level could be low or high. The colour of water should also give impression of water quality. Fish grows in pH of between 6.5 to 9. High PH may indicate high ammonium level. Testing needs to be done in order to avoid assumption of ammonium levels. High concentration of ammonium (NH4+) in fish pond can be very dangerous to fish.
Another thing that affects water quality is over fertilization. Pond fertilization is good because it provides natural food to the fish, fertilization result into the growth of algae which is green in colour which forms part of food web in the pond.
Nyamirini community based organization harvesting fish in kabondo-kasipul sub-county (HOMABAY COUNTY).