Cat fish rearing had been seen as one of the
lucrative farming business in Africa. A lot of people make their earning
livings in rearing of Cat Fish in Nigeria, mostly in the River line areas of
Nigeria like: Bayelsa, Calabar, Rivers and Niger Delta of Nigeria where the
demands for the product are mostly very high due to the culture of making fish
their main and favorite food. Also the demands are high from Hotel dealers in
those areas and the indigenes who sometimes engage in exporting smoked Cat Fish
in exchange of Foreign Currencies from United State and Europe. Now in this
article, we are going to look at how these cat fish are being spawned in the
water. But before we proceed let have understanding of the word “SPAWNING”. What do we mean by spawning? It
is an act or process of producing or depositing eggs by aquatic animals like
fish in the water. Spawn is the eggs and sperm released or deposited into water
by aquatic animals in order to reproduce aquatic lives species of its kind.
The spawning process in a cat fish can be induced,
and this is done by getting a very good species of Cat Fish called Brood stock
which should be between 0.3kg and 2kg. Why
do we need it like that? It is because the seed of Catfish determines the
growth and health of the Fish after spawning. Now due to scarcity of good Fish
seed, cat fish farmers now induce female catfish in order to discharge their eggs
which are fertilized, incubated and there after hatched as well as nurtured for
6 to 7 weeks from fries to
fingerling with good zooplankton feed for this level and for the fish to meet
up to fingerlings which is the requirement suitable for the next or secondary
level rearing of Cat Fish.
In order to achieve the above result in Cat Fish
rearing, spawning process has so many gadgets or requirement to induce the
process as required by a fish farmer. The following gadgets are necessary and
they are: spawning net (Which is one
of the vital techniques in the spawning operation; in making of the net, one
may use pipes joined together to form a square shape). The net will also serve
as where the eggs will be layed in the water. The good thing things here is
that the net will float on top of the water to compare it to other method where
the net sinks inside water with four stones to hold it under net, other gadgets
like Tissue Paper, Razor Blade, Ovaprim,
Injection, and Saline Water are
needed for this induced spawning process. These gadgets has different functions
which we will still know during spawning but before we proceed to spawning
process we have to first weigh the Brood stock Cat Fish to use and then
determine the volume of ovaprim (drug
use to induce spawning) to suck and inject the fish. Now depending on Kilogram
(KG) of weight of the brood stock, each KG represents 0.5ML of Ovaprim for example: if the fish weigh 2kg, you need 1ML of Ovaprim to inject the fish. Another thing we need to put
into consideration before the spawning is Saline Water. Saline water simply means salt
and Water solution. It is required
when the sperm (male mate) of the
male bloodstock catfish is not sufficient. It is applied by rinsing the sperm
sack with it. It is necessary also to have a PH testing kit like Hydrometer in
order to ascertain the PH level of your water before spawning process.
Now, the spawning process begins a day before where
the spawning vat is washed thoroughly with detergent as well as the hatching
spawning net prepared in square shape with a pipe. Then, after washing it,
drain the water and rinse the vat, then wash with salt. After washing with
salt, rinse off and then add fresh clean water NOTE: The Vat is like the big space container where the spawning
will take place with other gadget filled with water. Now the next step is to
identify the female and male brood stock Catfish to use for the process which
is one of the puzzling issue every farmer have to master gradually as different
fish farmer hold different opinion or view in identifying Brood stock gender.
But if one can use these principles and they are:
(1)
Choose only Male and Female
fishes that weigh above 1Kg so that the
fries (which is the newly hatched fishes) will grow into big fishes as gene
tells
(2)
Make sure that the Male
organ (Crosses) and it is pink at the dot end.
(3)
When pressing out Female
fish that have eggs that separate from each other and are golden in color
(4)
Make sure that the tummy of
the female fish slightly protrudes out and when placed flat-faced down on
surface, make sure that the egg outlet of the female brood stock is dark in
color.
Now, after choosing the brood stock gender, based on
the above qualities, and then transport them separately to the farm where you
will continue the induced spawning process. Having done that, now we have to
inject the female brood stock Catfish to induce spawning, but before injecting,
make sure that it is free from stress when you bring it to the farm and make
sure you separate both gender brood stock Catfish to avoid fight to death. Next
is to drawn out Ovaprim based on the specifications we made earlier which is at
0.5ML per kg of the Brood Stock and two
persons are to hold the female brood stock as you inject the ovaprim just below
the neck region of the fish. Now, when injecting one should be careful not to
piece the needle so deep to the flesh; the injecting should be done at 9pm in
the night, so that one can strip the brood stock by 7 am the next morning.
Again, is to strip the female brood stock induced to
spawn. Now, 10 to 11 hours after injecting the female brood stock fish, the
fish must be stripped. As soon as one notices that the female brood stock fish
has started releasing its eggs by itself, one has to strip the female fully.
The process of stripping begins by removing the female fish from container or
bowl and held by two persons with a cloth. Provide a medium sized bowl where
the eggs will be stripped out and should be ready with two Napkins which two
persons that will grip the fish should use. The gripping should be done by one
at the tale while the other at the head region. Depending on the size of the
fish, the bowl should be held tightly especially when the fish is very big to
avoid the spilling of the eggs during stripping from the bowl due to struggling
of the fish. Now, during stripping keep on pressing its swollen tummy until it
becomes flat and as soon as you see blood coming out, then it is time to stop
pressing. But before stripping the female, the male sack should have been
removed by turning the male fish upside down and cut the stomach with razor
blade provided.
Now, gently take the Male mate which is in the sperm
sack of the male brood stock Cat fish, and use a new razor blade to cut the
Zig-zag end of the sack in to the bowl where the female eggs are stripped. The
rinsing of the sac should be done with a Saline Water solution which one may
purchase from a chemist shop, if you are confused in the mixing of salt and
water solution as required for this exercise. And it should be too watering
after rinsing the sperm sac begins to mix the solution together with plastic
spoon or chicken feather. Then after mixing, gently spread the solution inside
the Vat that was prepared for keeping the fishes.
Finally, during spreading some eggs might fall off
through the net, so one has to siphon them out with a hose from the pond in
order not to cause calamity later. Thereafter, cover the pond with its cover.
Leave for 24 hours and after the 24 hours open the pond to see the result of
your spawning process. If you are successful, you will see fries, very tiny
fishes sometime in thousands or millions depending on amount of eggs that
hatched. Sometimes it takes more than 24 hours during rainy for the fries to
hatch. Though if you don’t succeed, try it severally until you get it right and
when you get the result right you will not regret being a fish farmer. Thanks.
Written
by
ONYIA EMEKA HARFORD
+2348186388641
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