Catfish farming is one of
striving agribusinesses nowadays. It is a flexible agribusiness business that
can be virtually done anywhere provided there is space availability.
African Catfish, Clarias
gariepinus, is a very resilient and prolific fresh water fish. Other
Catfish species are Clarias batrachus; Clarias ictalurus; Clarias silurus etc.
Many farmers in sub-Saharan Africa have successfully raised large tons of Adult
Catfish for market purpose from fingerlings, but, only few knows how to produce
fingerlings. It is also important to know how to produce fries/fingerlings of
catfish. Being able to produce fries/fingerling will reduce cost of production
and provides assurance of getting better output. You can also be a good source
of quality and healthy fingerlings for other catfish farmers by building your
own hatchery. The quality of output you will get will depend on the quality of
breeder catfish used, breeding materials used and of course, the method used. A
fingerling can be allowed developed into juvenile, a juvenile is sold between N25 - N30 per one. A induced female brood stock can produce between 600 -
1000 eggs. The direct cost of production is usually low and profitable.
Before starting a catfish farm/hatchery,
a careful economic planning should be done. This may not be as complicated as
you think. A good way to start is to list the income and expenses you expect.
First, consider the income your catfish farming operation will produce.
Generally this means estimating the amount of catfish you will produce and the
price you will receive for them. Next, make a list of the expendable items you
will need to buy to produce your catfish. This will include feed, fingerlings,
labor, fuel, electricity, equipment, repair, etc. These are your variable
costs. It is important to make a list of costs for everything associated with
machinery. These are your fixed costs. Examples include wells, pumps, feed
bins, Plastic tanks, buildings, etc
Fingerlings production requires
artificial breeding of catfish, hence, before embarking on breeding exercise,
the following equipment/materials should be readily available; Hatchery Facility; Mature Broodstock (300-800 grams);
Weighing scale; a pair pincer; Calibrated jug; Thermometer; Mortar and Pestle;
Hack saw; Clean water supply; Plastic bowls; hatchery tanks and Spoon;
Distilled water; Salt; Hormones(Ovaprim; Ovatid); Dissecting kit; Syringes and
needles; Sharp knife/Knife; Kakaban (Egg net) or Substrate; Artemia.
It is important to sterilize all
equipment to be used with salt solution to avoid contamination. Breeding activities starts with
selection of healthy and matured broodstock (Male & Female spawner/fish), 8
– 12 month of age is preferred, and this should be gotten from a reputable
farm. A female broodstock/fish has well distended, swollen abdomen from which
ripe eggs can be obtained by slightly pressing the abdomen toward the genital
papilla. Ripe eggs are uniform in size, while a Male broodstock/fish has a
swollen, sometimes reddish coloured genital papilla. Female broodstock is
injected with synthetic hormones (ovaprim) with a dose of 0.5 ml/kg of body
weight. This injection is administered intra-muscularly at the dorsal
muscle in the evening hours. Cover the catfish head with a small wet towel to
avoid struggling. Ovulation of eggs will start after the hormonal
administration. Pituitary gland extract mixed with saline solution (9gSalt/1L H2O)
from catfish or carp can also be used. Male broodstock do not necessarily
need hormonal administration, however, recent research
by
Oguntuase & Adebayo (2014) revealed that,
Ovaprim and Ovatide (0.3 ml/kg) significantly increased volume of milt,
motility duration and percentage. The efficacy of these synthetic hormones was
evident on the reproductive performance as tested on the female C. gariepinus.
The use of these hormones in male fish is a means of boosting reproductive
performance and ensuring good and viable fish seeds. The injected female is returned to
water. The speed of ovulation depends on the water temperature, the higher the
temperature the quicker the eggs ovulate. Afterwards, the hatching tanks using
flow through system is prepared by filling it with fresh water and the egg
tray/net (kakaban) is gently placed on the hatching tank. Stripping of the
female broodstock should be done after latency period of 7 - 12 hours and
this is done by gently pressing the abdomen with a thumb from the pectoral fin
towards the genital papilla. Ovulated eggs will flow out easily in a thick jet
from the genital vent if the females responded well to the hormonal treatment.
The ovulated eggs are more or less transparent, flattened and a gram of egg
contains approximately 600 - 1000 eggs. The eggs are allowed to fall freely
into a clean and dry bowl. The male catfish cannot be stripped and consequently
the sperm can only be obtained by sacrificing a male. The male is killed and
thoroughly dried after which the testis is removed and cut with a scissors. The
milt is washed out with saline solution (0.9% sodium chloride) unto the
egg mass. Both sperm and eggs remain in their dormant state until they come in
contact with fresh water. Then, the eggs are fertilized by adding about the
same volume of clean water. The water and egg mass are mixed by gently shaking
of the bowl.
Eggs must be
stirred continuously until they are placed in the hatching tanks as the eggs
become sticky and without stirring will stick together into one clump.
Fertilization will take place in about 60 seconds, then, the sperm would have
lost its activity, the fertilized eggs are then ready for incubation in
hatching tanks. The fertilized eggs are uniformly spread on kakaban/egg
net (mesh size - 1 mm) placed on hatching tank. Flow through system
provided below the hatching tank will help maintain optimum oxygen level, if
there is no flow through system, ensure, water is renewed in order to
provide oxygen. Substrates (with floating ability, e.g strands of sack bundled
together, etc.) can also be used in absence of egg net. The substrates are
dipped into water containing the eggs and the eggs will stick onto the
substrates. They are then transferred into tanks, happa nets or basins, which
ever incubation container is available. The incubation of fertilized eggs is
for minimum of 24 hours and maximum of 48 hours. A very high temperature
between 27
oC & 30
oC favours quick hatching.
Hatchlings tend to stay in dark
places and should not be exposed to direct sunlight; therefore, it is important
to cover the incubator container with black tarpaulin. The hatched fries
(hatchlings) can survive on egg yolk for 3 days without feed. The fries should
be separated from the hatching tank and put into a clean tank to avoid fungal
infection and mortality, afterward, the fries shall be fed with Artemia, three
times a day until they develop into fingerlings.