What are the risks and challenges of fish farming in Nigeria? What are the problems faced in fish farming? What are the risks of catfish farming? What are the problems of fish farming in Nigeria? What are the risk factors in fish farming? How can we reduce the impact of overfishing? How does aquaculture affect the environment? How much does a catfish cost in Nigeria? Where can I market catfish? What is the life cycle of a catfish? What methods are used to preserve fish? What is fish pond management? How do you fertilize a fish pond? Which fish is best for farming? How can I be a successful fish farmer?
Problems Facing Catfish Farming And Solutions
There are many problems facing farming in Nigeria such as inadequate finance, land space, poor management, poor planning, diseases and bad water etc. but we are deliberating on diseases of hybrid catfish fry.
Nursing fries and fingerlings is an important stage before moving them to the grow-out ponds. At this stage, the fries are fragile and they require close attention.
Without adequate and appropriate care, the fries may die.
There are many reasons why fries become sick and die and they can be categorised as follows:
Poor Quality Fries:
The health of the fries depends to a large extent on the condition of the female Gunther catfish have a high rate of successful hatching when they are fertilizer with African catfish sperm. The fries from these broodstocks are usually healthy; they grow fast, rarely become diseased and are not easily infected.
Only those female broodstocks which have matured eggs should be selected for breeding. If the females are ready for artificial breeding, the injection of a small amount of hormone to stimulate the release of the eggs will allow the fish to be easily stripped.
If female broodstocks that have immature eggs are used for artificial breeding, the successful hatching rate is generally low because the eggs develop unevenly.
These fries grow slowly and are usually small and deformed, they do not eat, they become thin, their bodies are darker than normal and they lie still at the bottom of the pond.
If the fries float vertically at the water surface it means that they are too sick to be cured and the whole school or most of the fries in the pond will die.
To prevent this, select only matured female broodstock for artificial breeding. Fish should not be bred from November to February which is outside the normal breeding season.
Although artificial breeding in winter may be carried out successfully, nursing the fries in this season is very difficult as the fries will grow slowly due to cold weather.
Fries food such as Monia is hard to find, but most importantly, fries will be more prone to infection in winter than in summer or the rainy season.
There is also a high percentage of risk in releasing and raising fries in culture ponds in the winter as the fish grow more slowly and are more prone to infections and the mortality rates are higher.
Incorrect Nursing Method
Failure to use proper nursing techniques will cause stress and weakness in the fries as stressed and weak fries are vulnerable to infection and disease.
To prevent disease in nursing ponds the guidelines mentioned earlier for good nursing must be adhered to.
Your greater concern should be for the cleanliness of the pond which should be around 3 to 5 meters square and is a suitable size for easy cleaning.
It must be possible to siphon sediment from all parts of the pond.
Live or frozen Monia be fed to the fries even though it has been washed and treated with chemicals.
Decaying Monia may cause infection of the fries and must be fresh, under no circumstances should spoiled Monia be fed to the fries even though it has been washed and treated with chemicals. Decaying Monia causes infection of the fries and leads to an increase in mortality.
Research has shown that the most common pathogens of hybrid catfish fries are: protozoa, monogenean, immauredigenea (metacercaria) in fish gills, and bacteria.
These diseases and parasites will first attack weak fries, and then the pathogen will reproduce if the management of your nursing pond is not appropriate, increase it to a level where they can’t harm the other fries in the same pond.
If adequate treatment is not provided in time, all the fries in the pond could die.
Meanwhile, pathogens can spread to other ponds on the same farm through the sharing of equipment such as containers, hand nets and hoses.
These diseases can be treated if identified and the correct treatment is applied.
However, there are limits to how successful this treatment can be. If the fries have been very sick for a long period of time the pathogen may be eliminated but some of the fries may be too weak to recover.
During treatment, the mortality rate should reduce every day, for instance, using formalin to treat Trichodina, a protozoan that infects fries, the mortality rate will reduce by 50% to 80% after the first day and the fries will recover within 3 to 5 days.
Diseases Found In Fry Nursed In Cement Ponds
- SLIMY DISEASE: Fries float vertically at the water surface and have pale gills. They exhibit rotting of the skin, fins and the area around the lips and barbells. There are needle point-sized haemorrhages scattered over the entire body surface. Sometimes the fries swirling motion and if observed closely, the body will have a slew of white, cloudy mucous on it.
CAUSES OF INFECTION: Trichodina, Glossolalia, Scyphidia and Epistylis are the parasites found in diseased fish. Among them, Trichodina is the most serious cause of mortality.
Fries infected with Trichodina will have a thin white film of mucus on the skin. Trichodina will infect the skin and gulls, causing irritation to the fries. Eventually, the parasites induce small haemorrhages on the skin. When the fish are seriously ill they will have fin and gill rot.
Glossolalia, Scyphidia and Epistylis are found more on the gill filaments than on the skin. This parasite causes irritation, producing large amounts of mucus on the gills which is an obstacle to oxygen intake, the fish will therefore be weak and vulnerable to bacterial infections. Without proper treatment, more fries will die every day. If the disease is acute, the fries in the pond will die within 3 to 5 days.
TREATMENT: When the first clinical signs appear, the fries should be treated with 25PPM (Parts per Million) formalin (25PM = 25ml f formalin per 100 litres of pond water) and the treatment continued for 2 days. During the treatment, feeding should be reduced to half of the normal amount. After formalin treatment, the mortality rate should reduce and the fries should recover within 3 to 5 days.
- WHITE SPOT OR ITCH DISEASES: In the initial stages of the disease, there will be needle-point sized or smaller white spots all over the body. In the later stages, white patches will appear on the skin and fin rot will be evident. The fries swim slowly and the mortality rate is high, all the fries in the pond may die in 2 to 3 days.
CAUSES OF INFECTION: This disease is caused by Ichthyophthirius multifiliis (ICH), which are protozoa. There are two stages in the life of ICH, the first is a mature stage; the second is an immature stage. In the mature stage, ICH is found in layers of fish skin or gill that are big enough to be seen as white spots in the eyes. Chemical treatment at this stage is not successful as the ICH is below the surface of the skin.
When ICH fully develops, they detach from the fish skin and are reproduced by cell division within thick cell walls. When they mature, the cell ruptures and releases the immature ICH (tomites) into the environment. The tomites swim in the water and attach to the skin or gill filaments of the host within 24 hours. Attachment of tomites severely damages fish tissue and at this point, the fries will become weak and suddenly die. Affected fries have fin rot and pale bodies. If they do not receive prompt and adequate treatment, all the fries in the pond will die in 2 to 3 days.
TREATMENT: To eliminate white spot diseases it is necessary to use continuous treatments. Generally, the use of 25PM or 25ml formalin per 100 litres of pond water 3 times and at 3 days intervals is effective. After each treatment, the amount of Monia or other fries food given should be reduced to prevent pollution of the water. The procedure for the treatment is as follows:
- DAY ONE: Apply formalin for the first time
- DAY THREE: Drain about 75% of the water and replace it with fresh water and apply formalin for the second time
- DAY SIX: Drain about 20% to 25% of the water and replace it with fresh water and then apply formalin and leave for more than 2 days
- DAY EIGHT: After the eighth day, the fries should be healthy and strong and there should be no need to continue the treatment
Those are all the known risks and challenges of fish farming in Nigeria. This is where we shall be ending our CATFISH FARMING AS A BUSINESS IN NIGERIA SERIES and we hope the series so far has given you more insights?
This article was most recently revised and updated on April 11, 2022