culture of milk fish

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A seminar on CULTURE OF MILK FISH
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Contents

1. INTRODUCTION
2. TAXONOMIC POSITION
3. GEOGRAPHICAL DISTRIBUTION
4. DESCRIBTION, HABIT HABITAT
5. FRY COLLECTION
6. REARING OF FRY
7. TYPES OF CULTURE
8. GROW-OUT CULTURE
9. HARVESTING
10. SUMMERY
11. CONCLUSION
12. REFERENCES.

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Introduction

• Milkfish aquaculture first occurred around 800
  years ago in the Philippines and spread in
  Indonesia, Taiwan and into the Pacific.
  Traditional milkfish aquaculture relied upon
  restocking ponds by collecting wild fry. The
  milkfish (Chanos chanos) is the sole living
  species in the family Chanidae.
• Milkfish, being a euryhaline fish, can grow in
  any clean water environment salinity is not a
  requirement when growing this fish. However,
  transferring from saline water to freshwater
  should be done gradually in a process of
  acclimatization.

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TAXONOMIC POSITION

• Phylum - Chordata
• Subphylum - Vertebrata
• Class - Osteicthyes
• Order - Gonorhynchiformes
• Family - Chanidae
• Genus - Chanos
• Species - Chanos chanos

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GEOGRAPHICAL DISTRIBUTION

• Milkfish, Chanos chanos, is one of the two most
  important species being cultured in Asia, the
  other being carp.
• It is distributed throughout the entire tropical
  Indo-Pacific Ocean, from 40 E to about 100 W
  and 30 to 40 N to 30 to 40 S.
• It can tolerate wide ranges of salinity and
  temperature fluctuations.
• The Philippines, Indonesia and Taiwan are the
  center of geographic distribution.
• Their distribution coincides with coral reef
  areas where the water is warm (more than 20C),
  clear and shallow.

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Description

• Milkfish have a generally symmetrical and
  streamlined appearance, with a sizable forked
  caudal fin.
• They can grow to 1.70 metres but are most often
  about 1 metre in length.
• They have no teeth and generally feed on algae
  and invertebrates.

Habit Habitat
Milkfish is a large, long-live species
, and its habitat, behaviour, and food habits
changes with size and stage in the life cycle.
Essentially marine fish of the Indian and
across the Pacific Ocean , tending to school
around coasts and islands with reefs.
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Contd.

• Adult spawn at sea , the young fry live at sea
  for two to three weeks and then migrate to
  mangrove swamps, estuaries, and sometimes lakes
  and return to sea to mature sexually and
  reproduce.
• Highly euryhaline and can live in fresh to
  hyper-saline waters and can tolerate low oxygen
  level.
• They become sluggish lt 20C and mortality occurs
  at 12C.

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Culture system

• Common culture system Brackish water coastal
  pond farms.
• Farm may include Nurseries, rearing and
  wintering ( where fingerlings have to be
  over-wintered).
• Mono culture Fresh water ponds and reservoirs,
  Pen culture in fresh water lakes in Philippines.
• Poly culture Brackish water ponds ( tidal),
  farming with grey mullets, shrimps and sea bass.
  

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FRY COLLECTION

• Wild fry was the major source for milkfish
  culture until recent success in natural spawning
  and mass larval rearing in several milkfish
  farms.
• Milk fish dont mature and spawn naturally in
  confined waters. They seem to spawn in the sea
  near the coast and the small larvae (12-15 mm)
  occur periodically along the sandy coasts and
  in the estuaries.
• The instability of wild-fry supplies is an
  obvious problem for the culture of any aquatic
  species and milkfish is no exception.
• So farmers produce millions of hatchery fry for
  culture every year.

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METHOD OF FRY COLLECTION

• Fry collection methods of Southeast Asia carried
  out using fishing gear, such as fry barriers in
  Indonesia and the Philippines, filter bag nets in
  most of the fry-producing countries, seine nets
  in Sri Lanka and the Philippines. The selection
  of fishing gear is based on the topography of
  fishing ground and ocean currents.
• It is important to realize that driving the fry
  into the net, rather than filtering them through
  it, results in higher survival.

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Collection of milkfish fry using a push net
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Seed production (induced breeding)

• Attempts have been made to develop milk fish
  hatchery to meet the increasing demands.
• Sexes can be distinguished by external
  characteristics. Three openings in the
  urinogenital (anal) region of mature female
  milkfish.
• Sexually mature males possess only two openings.
• Mature female collected from sea can be induced
  to spawn using gonadotropin-releasing hormone
  analogue (GnRH-A).
• Fecundity estimates of 0.3 to 1 million eggs per
  kg body weight.
• Survival rates under experimental condition
  varies between 9-47.
• A newly-hatched milkfish larvae measures 3.5 mm
  total length.

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Rearing of fry

• Fry can be introduced into rearing ponds after a
  brief period of acclimatization in small nursery
  ponds of about 1000 to 4000 sq mt.
• Many farmers have adopted the practice of raising
  mainly planktonic organisms as food for milkfish
  fry.
• Deep ponds are used for better growth of
  phytoplankton and zooplankton organisms.
• Pond-reared milkfish feed mainly on either lablab
  (a complex mat of bluegreen algae, diatoms and
  associated invertebrates) or lumut (mainly
  filamentous green algae).

Lablab
Lumut
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PEN CULTURE

• This system was introduced in the Philippines in
  1979 in the Laguna Lake. At that time, the lake
  had a very high primary productivity, which met
  the nutritional needs of milkfish , because of
  the low rate of input and the high rate of
  return.
• As the primary production of the lake could not
  meet this sudden expansion of aquaculture, and
  feeding became necessary to meet the nutritional
  requirements of the cultured fish, the pen
  culture practices developed in lakes later
  introduced into inter-tidal areas in the
  Philippines river, estuaries as well.
• Pen operators stock fingerlings at
  30,000-35,000/ha and provide supplemental
  commercial diets. However, disease spreads among
  culture pens and causes mass mortality.

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CAGE CULTURE

• Fish cages are smaller and more restricted
  enclosures that can be staked in shallow waters
  or set-up in deep water with appropriate floats
  and anchors.
• Cage farming of milkfish is commonly carried out
  in marine waters along coastal bays.
• Stocking rates are quite high, from 5 up to 30/m³

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Pond culture

• Culture of milkfish in ponds may be in shallow or
  deep water systems
• SHALLOW WATER CULTURE
• Shallow water culture is practiced mainly in
  Indonesia and Philippines.
• Milkfish are traditionally cultured in shallow
  water.
• Brackish water ponds in which the growth of
  benthic algae is encouraged through inorganic or
  organic fertilization.

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DEEP WATER CULTURE

• Deep water culture was developed in the mid 1970s
  in response to the decline of profitability of
  shallow water culture, and the limited and
  increasing value of land and manpower resources.
• Most deep-water milkfish ponds have been created
  by converting either shallow water ponds or
  freshwater ponds, with a depth of 2-3 m.
• They so far have shown less susceptibility to
  disease than shallow ponds.
• Production from these systems has sharply
  increased.

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PREPARATION OF THE PONDS

• The preparation of the ponds starts about two
  months before the fry are introduced.
• Construction and setting up of the inner wooden
  gates in the catching ponds.
• Repairing of the dikes facing the main canal.
• Poisoning of the ponds in order to avoid unwanted
  species.
• The pond bottom is leveled in such a way that it
  slopes gradually towards the deepest portion of
  the pond at the sluice gate.

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Contd.

• The pond is then dried and exposed to the sun for
  2 or 3 days.
• Pests and predators that reduce milkfish
  production, are eliminated or controlled either
  by-
• a) mechanical or b) chemical methods.
• Lime is applied to ponds to make the soil pH
  neutral or alkaline.

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PREPARATION OF POND
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Natural food production

• Three types of natural food are produced in
  brackish water ponds, namely lablab, lumut and
  plankton.
• Lablab production
• Lablab is a complex of minute plants and animals
  occurring initially on the pond bottom as a
  brownish, greenish or yellowish film.
• It grows well during the dry months in ponds with
  hard bottoms and salinities ranging from 25 to 35
  ppt.

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Contd.

• In order to produce lablab, chicken manure is
  scattered, at a rate of 2 tonnes per ha, over
  previously dried ponds from one to four years old
  .
• Sufficient water is then admitted to barely cover
  the pond bottom.
• Fish production in ponds with lablab ranges from
  1.5 to 3 tonnes per ha per year.

Lablab
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Lumut production

• Filamentous green algae or lumut of the species
  Chaetomorpha linum, Cladophora sp. grow well
  during rainy seasons in ponds with soft bottoms.
  Since lumut is poorly digested by milkfish fry
  and fingerlings it is usually allowed to
  decompose or dry before it is fed to milkfish.
• Lumut is produced in the same manner as lablab
  but the water depth ranges from 40 to 60 cm.
  Excessive growth of lumut is undesirable because
  it competes with milkfish for living space. Fish
  production in ponds with lumut ranges from 0.2 to
  0.5 tonnes per ha per year.

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PLANKTON PRODUCTION

• To produce plankton, 70 to 100 cm of water is
  admitted to a previously drained and well
  prepared pond.
• Fertilizer is added while or after admitting
  water to the pond. Plankton blooms, characterized
  by the greening of pond water, occur within one
  or two weeks. When plankton blooms, the Secchi
  disc visibility is from 15 to 40 cm.
• Fish production in ponds with plankton ranges
  from 1.5 to 3 tonnes per ha per year.

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STOCKING PRACTICES

• In the traditional pond system
• a) Nursery ponds with abundant lablab are
  stocked _at_ 30 to 50 fry per m2
• b) In transition ponds _at_ 10 to 15 fingerlings
  per m2.
• c) Rearing ponds with lablab, fry stocked _at_
  1,500 to 3,000 fingerlings per ha and
• d) Ponds with plankton, fingerlings are
  stocked _at_ 3,000 to 5,000 per ha.

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GROW-OUT CULTURE

• There are three cropping systems practiced in the
  Philippines the straight culture, the
  progression and the modular methods.
• In the straight culture method, the fingerlings
  are stocked and reared to marketable size in one
  rearing pond for two to four months.
• In the progression method, fingerlings are reared
  to marketable size in two different ponds
  fingerlings to post-fingerlings in one pond and
  post-fingerlings to marketable size in another.

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Contd.

• An improvement of the progression method is the
  modular method. The fish are reared successively
  in three different ponds connected to one another
  and with progressively increasing areas in a
  124 or 139 ratio.
• The stock is reared for 45 days in the first pond
  and subsequently transferred to the second and
  third ponds. The vacated pond is immediately
  prepared for the next stock.

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Production cycle
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HARVEST

• The most commonly used method for harvesting
  milkfish that have reached marketable size is the
  water current method.
• This method takes advantage of the tendency of
  the fish to swim against the current.
• The method is carried out by draining water in
  the pond to induce fish to swim through the gate.
  
• The gate is then closed when all the fish have
  been compounded.
• Harvesting can also be done by the use of seine
  nets and gill net.

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Harvesting of milkfish using a seine
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Milk Fish Culture flow chart
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Global aquaculture production of Chanos chanos

• Global annual aquaculture production of milkfish
  has increased every year since 1997 by 2005 it
  had risen to nearly 5,95000 tonnes. The most
  important producers at this time were the
  Philippines (289 000 tonnes), Indonesia (254 000
  tonnes) and Taiwan Province of China (50 000
  tonnes).

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Summery

• Milkfish (Chanos chanos) is one of the most
  important food fish species in the world. In
  Indonesia, Taiwan and the Philippines, more than
  a quarter of a million tonnes of milkfish are
  harvested annually in brackish water ponds
  contributing roughly 60 of the total fish
  production from aquaculture in South-East Asia.
• Milk fish fry is collected from wild source until
  recent success in natural spawning and mass
  larval rearing in several milkfish farms. Milk
  fish culture is done in mainly three culture
  method pen culture , cage culture and pond
  culture. After becoming table size the fishes are
  harvested using water current method and also
  seine net , gill net.
• The demand of milk fish is increased day by day
  due to its high market value and high production
  rate.

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CONCLUSION

• Milkfish farming in Indonesia, Taiwan and the
  Philippines started about 4-6 centuries ago.
  Culture methods in a variety of enclosures are
  constantly being improved upon.
• But even in the present days the culture of milk
  fish in India is based on traditional extensive
  culture whereas in the other countries it is far
  advanced.
• Fish farmers also faces the problems of disease
  and fry feeding.
• In recent years the possibility of using
  milkfish juveniles as bait for tuna long lining
  has started to be investigated, opening up new
  markets for fry hatcheries.

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References

• www.fao.org
• www.wikipedia.com
• www.fishbase.org
• Aquaculture principles and practices T.V.R
  Pillay M.N. Kutty

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THANK YOU