Fish farming involves raising fish commercially, usually for food. The most common fish species raised on farms are salmon, carp, tilapia, seabass, catfish, and cod. There is increasing demand for fish which has resulted in overfishing, so fish farming offers another source. Fish farms can be extensive or intensive. Extensive farms rely on natural food sources while intensive farms require artificial feeding and water treatment. Common fish farm systems include cages, ponds, composites of different fish species, and integrated systems that reuse water. Issues with fish farms include the use of wild fish in feeds and the high densities that can cause disease.
2. Fish farming is the principal form of aquaculture,
while other methods may fall under mariculture. Fish
farming involves raising fish commercially in tanks or
enclosures, usually for food. A facility that releases
young (juvenile) fish into the wild for recreational
fishing or to supplement a species' natural numbers is
generally referred to as a fish hatchery. The most
common fish species raised by fish farms are
salmon, carp, tilapia, European
seabass, catfish and cod.
There is an increasing demand for fish and
fish protein, which has resulted in
widespread overfishing in wild fisheries. Fish
farming offers fish marketers another source.
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5. 2.M A J O R C A T E G O R I E S O F F I S H A Q
# E X T E NS I V E A QUA CUL T URE
# I NT E NS I V E A QUA CUL T URE
EXTENSIVE AQUACULTURE
Limiting for growth here is the available food supply by
natural sources,
commonly z o o p l a n k t o n f e e d i n g
o n p e l a g i c a l g a e or b e n t h i c animals,
s u c h
a s c r u s t a c e a n s and m o l l u s k s . T i l
a p i a species filter feed directly
on p h y t o p l a n k t o n , which makes higher
production possible. The photosynthetic production can be
increased by f e r t i l i z i n g the p o n d
wa t e r wi t h a r t i f i c i a l
f e r t i l i z e r mi x t u r e s , s u c h
a s p o t a s h ,p h o s p h o r u s ,n i t r o g e n
and micro-elements. Because most fish
are c a r n i v o r o u s , they occupy a higher place in
the t r o p h i c c h a i n and t h e r e f o r e
o n l y a t i n y f r a c t i o n o f
p r i ma r y p h o t o s y n t h e t i c
p r o d u c t i o n (t y p i c a l l y 1%) w i l l
b e c o n v e r t e d i n t o h a r v e s t -
a b l e f i s h .
Another issue is the risk of a l g a l b l o o m s .
Wh e n t e m p e r a t u r e s , n u t r i e n t 5
s u p p l y a n d a v a i l a b l e s u n l i g h t
a r e o p t i ma l f o r a l g a l g r o w t h ,
6. INTENSIVE AQUACULTURE
In these kinds of systems fish production per unit
of surface can be increased at will, as long as
sufficient o x y g e n , fresh water and food are
provided. Because of the requirement of sufficient
fresh water, a massive w a t e r
p u r i f i c a t i o n system m u s t b e
i n t e g r a t e d i n t h e f i s h
f a r m. A c l e v e r w a y t o
a c h i e v e t h i s i s t h e
c o mb i n a t i o n
h y d r o p o n i c h o r t i c u l t u r e
and w a t e r t r e a t m e n t . The cost of
inputs per unit of fish weight is higher than in
extensive farming, especially because of the high
cost of f i s h f e e d .
Expressing eggs from
a female rainbow
trout
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Essential here is a e r a t i o n of t h e
wa t e r , a s f i s h n e e d a
7. Specific types of fish farms
Cage system
Fish cages are placed in lakes, ponds, rivers or
oceans to contain and protect fish until they
can be harvested. The method is also called
"off-shore cultivation[6]" when the cages are
placed in the sea. They can be constructed of a
wide variety of components. Fish are stocked in
cages, artificially fed, and harvested when they
reach market size.
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8. Irrigation ditch or pond systems
These use irrigation ditches or farm ponds to raise
fish. The basic requirement is to have a ditch or
pond that retains water, possibly with an above-
ground irrigation system. Using this method, one
can store one's water allotment in ponds or
ditches, usually lined with bentonite clay. In small
systems the fish are often fed commercial fish food,
and their waste products can help fertilize the
fields. In larger ponds, the pond grows water plants
and algae as fish food.
Control of water quality is crucial. Fertilizing,
clarifying and pH control of the water can increase
yields substantially.
Yields can be low if the fish grow ill from electrolyte
stress. 8
9. Composite fish culture
The Composite fish culture system is a technology
developed in India by the Indian Council of Agricultural
Research in the 1970s. In this system both local and
imported fish species, a combination of five or six fish
species is used in a single fish pond. These species are
selected so that they do not compete for food among
them having different types of food habitats.
Fish used in this system include catla and silver
carp which are surface feeders, rohu a column feeder
and mrigal and common carp which are bottom
feeders. Other fish will also feed on the excreta of the
common carp and this helps contribute to the efficiency
of the system which in optimal conditions will produce
3000–6000 kg of fish per hectare per year.
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10. Integrated recycling systems
One of the largest problems with freshwater aquaculture is that it
can use a million gallons of water per acre (about 1 m³ of water
per m²) each year. Extended water purification systems allow for
the reuse (recycling) of local water.
A hydroponic bed is placed near, above or between them.
When tilapia are raised in the tanks, they are able to eat algae,
which naturally grows in the tanks when the tanks are properly
fertilized.
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11. Classic fry farming
This is also called a "Flow through system“. . . Trout
and other sport fish are often raised from eggs
to fry or fingerlings and then trucked to streams
and released. Normally, the fry are raised in long,
shallow concrete tanks, fed with fresh stream
water. The fry receive commercial fish food in
pellets.
** baby fish are called fry.
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12. Issues
Many cultured fishes (tilapia, carp, catfish, many
others) require no meat or fish products in their diets.
Top-level carnivores (most salmon species) depend on
fish feed of which a portion is usually derived from wild
caught (anchovies, menhaden, etc.).
Vegetable-derived proteins have successfully
replaced fish meal in feeds for carnivorous fishes, but
vegetable-derived oils have not successfully been
incorporated into the diets of carnivores.
Secondly, farmed fish are kept in concentrations
never seen in the wild (e.g. 50,000 fish in a 2-acre
(8,100 m2) area.[11]) with each fish occupying less
room than the average bathtub. This can cause
several forms of pollution. Packed tightly, fish rub
against each other and the sides of their cages,
damaging their fins and tails and becoming sickened
with various diseases and infections. This also causes
stress.
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13. Labeling
The common name on canned fish must be shown in
letters of equal height and prominence and indicate
whether the product has been prepared by mincing,
flaking or other special process; from selected parts of fish
for dietetic use.
>>The geographic location where the fish has been
harvested may be added to the common name,
however this is optional.
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14. Indoor fish farming
An alternative to outdoor open ocean cage aquaculture,
is through the use of a recirculation aquaculture system
(RAS). A RAS is a series of culture tanks and filters where
water is continuously recycled and monitored to keep
optimal conditions year round. To prevent the
deterioration of water quality, the water is treated
mechanically through the removal of particulate matter
and biologically through the conversion of harmful
accumulated chemicals into nontoxic ones.
One of the drawbacks to recirculation aquaculture
systems is water exchange.
Because of its high capital and operating costs, RAS has
generally been restricted to practices such as broodstock
maturation, larval rearing, fingerling production, research
animal production, SPF (specific pathogen free) animal
production, and caviar and ornamental fish production. 14
15. Slaughter methods
H U MA N E I N H U MA N E
1.Percussive stunning. 1.Air Asphyxiation.
2.Electric stunning : suffocation in the open
can be humane when a air. Takes15 minutes to
proper current, duration, induce death.
conductivity, and 2. Ice baths / chilling
temperature are present. dampen muscle
One advantage is that in- movements by the fish
water stunning allows fish and to delay the onset of
to be rendered post-death decay.
unconscious without 3. CO2 : narcosis
stressful handling or
displacement. 4. Exsanguiation without
stunning:
taken up from water, held
still, and cut so as to
cause bleeding.
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