4. Fish Rearing
Also known as fish farming
Raising fish commercially in tanks or
enclosures such as fish ponds, usually
for food.
Worldwide, the most important fish
species produced in fish farming are
carp, tilapia, salmon, and catfish.
5. Purpose of fish rearing
Better use of land and water.
Source of food for humans
Source of income
6. Categories
Fish farming may involve use of
1)local photosynthetic production
(extensive)
2)fish that are fed with external food
supply (intensive)
3)Both (semi intensive)
7. Intensive aquaculture
Aimed for achieving maximum
production of fish from a minimum
quantity of water.
Fishes are fed on artificial food.
Relies on technology to raise fish in
artificial tanks, ponds and raceways at
very high densities.
9. Extensive Aquaculture
Culture and rearing in which human
intervention is concentrated on the
reproduction of stock, in addition to
capture.
E.g. prawns, muscles, seaweed, carp,
tilapia, tuna and salmon.
10. Characteristics
Food supply : utilizes natural
photosynthetic production of food
(algae, plankton, molluscs ,
crustaceans) to feed them.
Suitable Region: areas of coastal
mangrove, swamps, marshes,
estuaries.
Stocking and production: low stocking
densities.
11. Fish farms
1) Cage system
2) Copper-alloy nets
3) Irrigation ditch or pond systems
4) Composite fish culture
12. 1)Cage system
Also known as "off-shore cultivation”
when the cages are placed in the sea
Placed in lakes, bayous, ponds, rivers, or
oceans
Fish are stocked in cages, artificially fed,
and harvested when they reach market
size.
Advantages : Many types of waters can
be used (rivers, lakes, filled quarries,
etc.), many types of fish can be raised,
and fish farming can co-exist with sport
fishing and other water uses.
15. 2)Copper-alloy nets
Important netting materials in
aquaculture
Are antimicrobial (destroy bacteria,
viruses, fungi, algae, and other
microbes)
Copper-zinc brass alloys are deployed in
commercial-scale aquaculture operations
in Asia, South America, and the USA
(Hawaii).
Advantage: resistance of organism
growth on copper alloy nets provides a
cleaner and healthier environment for
16.
17. 3)Irrigation ditch or pond
systems
Use irrigation ditches or farm ponds to
raise fish.
Basic requirement is to have a ditch or
pond that retains water, possibly with
an above-ground irrigation system.
In small systems, the fish are often fed
commercial fish food.
In larger ponds, the pond grows water
plants and algae as fish food.
18.
19. 4)Composite fish culture
Comprise of a combination of both
local and imported fish.
Five or six fish species having
different habitat are used in a single
fish pond.
E.g. catla and silver carp (surface
feeders) rohu (column feeder)
common carp (bottom feeders).
22. 1)Age
Embryo of fish grow more than the
aged fish because of its efficiency
being 58% as compared to that of
aged fish which is 15% .
23. 2)Type of food
Feeding on artificial food is less
efficient as compared to feeding on
natural food.
Fishes feeding on high protein food
grows well.
Fishes feeding entirely on roughage
will not grow well.
