Huge population growth
around the world requires a sustainable source of protein. Demand for fish is
growing every day while fisheries struggle to meet the huge demand. To fill the
gap fish farming has become very lucrative.
Advancement in technology
better knowledge of feed/water management has increase production. To meet this
demand there are different ways fish farmers produce the stock. We have inland
fishery, estuary fishery, marine, freshwater fishery. An estuary is were river
and sea meet it involves wetlands swampy regions.
Advantages of Sewage- Fed Fish Culture
There are many advantages to
sewage fed fish culture like reduction in pollution load in ecosystem. The main
advantage is low cost high production rate.
Another is the avoidance of
environmental damage related to untreated sewage. More pros include zero
supplementary feeding or manure. A farmer also benefits from high nutrient
content in sewage.
Advantages
reduction in pollution load in ecosystem
low cost
high production rate
avoidance of environmental damage
zero supplementary feeding
no – manure
high nutrient content in sewage
Fish Feeding
Using animal waste in fish
pond is not a new practice. A good example is the integrated farming system
that incorporates poultry chicken cages suspended over fishing ponds. The waste
in combination with waste feed is eaten by the fish.
However farmers that
practice sewage fish culture have a few choices in feed. Apart from produced/formulated
feed they use poultry waste. Others are plant sourced feed, biogas slurry or
sewage-fed fish.
Types of fish feed
formulated feed
plant sourced
feed
biogas slurry
sewage-fed fish
Plant based feed
Aquatic plants are the
primary plant source for feed. The type of feed vegetation depends on your
geographical location. Indian areas with sustainable cash crops are Bihar,
Madhya and Pradesh.
Season also dictates which
crop is available at the time. You have decomposed leaves in combination with
organic matter. Others are Tmakhana, Trapa, Euryale Ferox, Napier grass
planted around the perimeter of the pond. Other vegetation to consider are
Potamogento, Hydrilla rapier, Ottella.
India
Plant Based Feed
Tmakhana
Trapa
Euryale
Ferox
Napier grass
Potamogento
Hydrilla rapier
Ottella.
Fish
Perfect for Sewage Feed Fish Culture
Not every fish is good for sewage fish culture. The fish
must be hardy, rugged and able to survive in harsh environment. Most farmers
combine different types of fish in the pond system. Fish to stock are silver
carp, rohu, grass carp, common carp, catla, mrigal.
Type
of Fish in this System
silver carp
rohu
grass carp
common carp
catla
catfish
How
to Build the Pond
The first step is to select a site and dig a pond. If you
have an existing pond drain the water then fill. Leave the pond for a week
before stocking with grass carp and feed immediately till they are over full.
The aim is to leave some uneaten feed lying about in the
pond. After another week stock with some of the other fish mentioned above then
feed again till satiation.
Plant hybrid napier 1 root slip/sq m with 5 t farmyard
manure/2000 sq m. tis quality of hybrid napier will produce about 20t naier to
feed fish 0.1ha pond. Irrigate every two weeks cut grass every two and half
months.
Advantages
and Limitations of integrated system
Limitations include huge quantities of grass is needed to
feed the stock. Others are regular weed cutting and proper irrigation.
There is also the challenge of transportation to market
and unavailability of grass carp fingerlings. Advantages include good
utilization of pond resources, availability of napier seed, multiple steams of
income.
Limitations
huge quantities of grass to feed stock
regular weed
regular cutting
proper irrigation
challenge of transportation to market
unavailability of grass carp fingerlings
Advantages
good utilization of pond resources
availability of seed
multiple steams of income
Pond
Management
Sewage water used in the culture has rich nutrient
components. The culture effectively reduces feed cost, reduces need for
fertilizer. A farmer is guaranteed huge profit, dense stocking good results.
The sewage water is not stagnate but allowed to flow and treated.
Treatment include storage, sedimentation, and organic matter decomposition.
Dilution is done by introducing freshwater at 1:5 part freshwater.
This is to reduce concentration of toxins to reduce smell
and encourage algae growth. Some introduce duckweed while pond undergoes
process of liming.
How
to use Animal Waste in Pond
The farmer uses small quantity of livestock waste like
waste feed and feces. The inorganic material is introduced into the pond.
Biological reactions include phytoplankton, zooplankton, detritus accumulates
at bottom of pond.
Phytoplankton through photosynthesis adds dissolved
oxygen into the pond. Two technique are placing the pen over the pond or close
to the pond.
Dangers
Associated dangers are pungent smelling water, grey or
brownish water, gas bubbles in water or fish gasping for air.
Harvesting
Fish
Stop manure load 2 days before harvesting and partially drain pond. Seining will reduce mortality use net to catch and transfer in clean water for 6 hours.
