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OYSTER CULTURE OYSTER CULTURE

Oyster Culture

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Page 1: Oyster Culture

OYSTER OYSTER CULTURECULTURE

Page 2: Oyster Culture

INTRODUCTIONINTRODUCTION Oysters are bivalve mollusks occurring Oysters are bivalve mollusks occurring

worldwide in temperate, sub-tropical and worldwide in temperate, sub-tropical and tropical seas.tropical seas.

They are sedentary with pelagic larval They are sedentary with pelagic larval stages.stages.

They are filter feeders, feed low in the food They are filter feeders, feed low in the food chain.chain.

The oyster is a highly esteemed sea food The oyster is a highly esteemed sea food and considered a delicacy in USA, Europe, and considered a delicacy in USA, Europe, Japan etc..Japan etc..

In India there is a growing demand in some In India there is a growing demand in some part of the countries.part of the countries.

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Contd..Contd.. Six species of edible oyster are mainly Six species of edible oyster are mainly

culture in India-culture in India- Crassostrea madrasensisCrassostrea madrasensis – Indian – Indian

backwater oyster.backwater oyster. Crassostrea rivularisCrassostrea rivularis – Chinese oyster. – Chinese oyster. Crassostrea graphoidesCrassostrea graphoides – West Coast oyster. – West Coast oyster. Saccostrea cucullataSaccostrea cucullata – Indian rock oyster. – Indian rock oyster. Saxostrea cucullataSaxostrea cucullata – Bombay oyster. – Bombay oyster. Hypotissa hyotisHypotissa hyotis – Giant oyster. – Giant oyster.

Among these, the first 4 species are having Among these, the first 4 species are having commercial importance.commercial importance.

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OYSTER CULTURE IN DIFFERENT OYSTER CULTURE IN DIFFERENT PARTS OF THE WORLDPARTS OF THE WORLD

Chile – Chile – Crassostrea gigas, Ostrea chilensisCrassostrea gigas, Ostrea chilensis Cuba – Cuba – Crassostrea rhizophoraCrassostrea rhizophora Jamaica – Jamaica – C. rhizophoraC. rhizophora Malaysia – Malaysia – C. belchoriC. belchori Mauritius – Mauritius – Saccostrea cucullataSaccostrea cucullata Mexico – Mexico – C. gigas, C. virginicaC. gigas, C. virginica Phillipines – Phillipines – C. gigasC. gigas China – China – C. gigas, C. plicatula, C. rivularis.C. gigas, C. plicatula, C. rivularis. Australia – Australia – C. gigas, C. commercialis.C. gigas, C. commercialis.

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History of oyster cultureHistory of oyster culture As early as the first century B.C, the Romans As early as the first century B.C, the Romans

were the first to develop simple methods of were the first to develop simple methods of collecting oyster seeds and growing them for collecting oyster seeds and growing them for food.food.

The Japanese developed ‘Habitat culture The Japanese developed ‘Habitat culture technique’ technique’ ieie culture in nets fixed to bamboo culture in nets fixed to bamboo poles during the seventeenth century.poles during the seventeenth century.

In the early part of the 20In the early part of the 20thth century, small century, small and large consignments of oysters were and large consignments of oysters were moved from Japan to the West Coast of North moved from Japan to the West Coast of North America, where fisheries quickly developed.America, where fisheries quickly developed.

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Contd..Contd.. The Pacific oysters was introduced to The Pacific oysters was introduced to

many countries.many countries. Each of the country has their own Each of the country has their own

indigenous species cultured from many indigenous species cultured from many years ago.years ago.

HISTORY OF OYSTER CULTURE IN INDIAHISTORY OF OYSTER CULTURE IN INDIA In India, pioneering attempts were made In India, pioneering attempts were made

by James Hornell in 1910 in developing by James Hornell in 1910 in developing Oyster culture in Madras state.Oyster culture in Madras state.

The first available information on oysters The first available information on oysters resources were made by Alagarswami and resources were made by Alagarswami and Narasimham (1973) followed by Rao Narasimham (1973) followed by Rao (1974).(1974).

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Contd..Contd.. The CMFRI undertook scientific The CMFRI undertook scientific

investigation at Tuticorin from early 70’s.investigation at Tuticorin from early 70’s. Oyster are traditionally consumed locally Oyster are traditionally consumed locally

however, the commercial oyster culture however, the commercial oyster culture by villagers began only from 1996.by villagers began only from 1996.

CHARACTERISTICS OF OYSTER-CHARACTERISTICS OF OYSTER-The shape of the oyster shell is highly The shape of the oyster shell is highly variable. If grown individually on a soft variable. If grown individually on a soft bottom, the shell tends to be smooth and bottom, the shell tends to be smooth and elongated. If grown on hard bottom, the elongated. If grown on hard bottom, the shell becomes more circular and the shell becomes more circular and the lower valves become deeper.lower valves become deeper.

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Contd..Contd.. Proximity to the oysters, when grown in a Proximity to the oysters, when grown in a

cluster causes great distortions in the cluster causes great distortions in the shape of the shell. This process is called shape of the shell. This process is called xenomorphism. xenomorphism.

CRASSOSTREACRASSOSTREA MADRASENSIS- MADRASENSIS- Occurs all along the Indian Coasts and Occurs all along the Indian Coasts and

Andamans.Andamans. It grows upto a length of 22cm.It grows upto a length of 22cm. Requirements-Requirements-

Temperature- 22.8 - 34.5Temperature- 22.8 - 34.5Salinity - 7.2 - 34.1 pptSalinity - 7.2 - 34.1 pptpH - 7.9 - 8.3pH - 7.9 - 8.3

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Contd..Contd.. Sexes are separate, however Sexes are separate, however

hermaphroditism was observed and it was hermaphroditism was observed and it was considered transitional stage to sex considered transitional stage to sex reversal.reversal.

They are protoandrous.They are protoandrous. The fecundity of The fecundity of C. madrasensisC. madrasensis has been has been

estimated vary between 10-15 million eggs.estimated vary between 10-15 million eggs. The oyster obtain food by collecting The oyster obtain food by collecting

particles suspended in the water column. particles suspended in the water column. The particulate food comprises a wide range The particulate food comprises a wide range of living micro-organisms, detritus and of living micro-organisms, detritus and inorganic particles.inorganic particles.

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Contd..Contd..

Among the three Among the three commercial oyster commercial oyster

species, species, C.C. madrasensismadrasensis grows fast and attains grows fast and attains

greater maximum greater maximum length.length.

The growth rate differs The growth rate differs in different places and in different places and attains about 60-90mm attains about 60-90mm

in one year.in one year. It is more widely It is more widely

distributed, is distributed, is euryhaline.euryhaline.

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CULTURE OF OYSTERCULTURE OF OYSTER In India, work on oyster culture was In India, work on oyster culture was

taken up during 1970’s at the Tuticorin taken up during 1970’s at the Tuticorin Research Centre of CMFRI, Tuticorin.Research Centre of CMFRI, Tuticorin.

Oyster spat was successfully produced Oyster spat was successfully produced in the Shellfish Hatchery at Tutocorin in the Shellfish Hatchery at Tutocorin in 1982 and this paved the way to in 1982 and this paved the way to undertake location testing studies at undertake location testing studies at several places along the Indian Coast several places along the Indian Coast to find out their suitability for oyster to find out their suitability for oyster culture.culture.

In India, work on oyster culture was In India, work on oyster culture was taken up during 1970’s at the Tuticorin taken up during 1970’s at the Tuticorin Research Centre of CMFRI, Tuticorin.Research Centre of CMFRI, Tuticorin.

Oyster spat was successfully produced Oyster spat was successfully produced in the Shellfish Hatchery at Tutocorin in the Shellfish Hatchery at Tutocorin in 1982 and this paved the way to in 1982 and this paved the way to undertake location testing studies at undertake location testing studies at several places along the Indian Coast several places along the Indian Coast to find out their suitability for oyster to find out their suitability for oyster culture.culture.

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TECHNOLOGY OF TECHNOLOGY OF OYSTER CULTUREOYSTER CULTURE

The technology of oyster culture consists The technology of oyster culture consists of two important phases namely oyster of two important phases namely oyster seed production and farming to grow seed production and farming to grow oyster seeds to marketable size.oyster seeds to marketable size.

OYSTER SEED PRODUCTION-OYSTER SEED PRODUCTION- Natural spat collection-Natural spat collection-

The substratum provided to the oyster The substratum provided to the oyster larvae for attachment is known as ‘clutch’ larvae for attachment is known as ‘clutch’ or ‘collector’.or ‘collector’.

The clutch maybe oyster shells, coconut The clutch maybe oyster shells, coconut shells , mussel shell etc.shells , mussel shell etc.

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Contd..Contd.. These are arranged in nylon rope or wire as These are arranged in nylon rope or wire as

strings and suspended from racks in the water at strings and suspended from racks in the water at suitable spot.suitable spot.

The larval period of The larval period of C. madrasensisC. madrasensis is 15-20 days is 15-20 days and such an exposure of collectors will be ideal and such an exposure of collectors will be ideal just after a week or 10 days of spawning activity.just after a week or 10 days of spawning activity.

Low salinity is reported to have a profound Low salinity is reported to have a profound negative influence on oyster larval settlement negative influence on oyster larval settlement and subsequent spat survival. and subsequent spat survival.

In general, March- April and October-December In general, March- April and October-December are the seasons of spatfall for are the seasons of spatfall for C. madrasensisC. madrasensis, , July- September for July- September for Crassostrea graphoidesCrassostrea graphoides..

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Contd..Contd.. Seed production in the hatchery-Seed production in the hatchery- Several factors are to be considered in the Several factors are to be considered in the

selection of site for establishing oyster selection of site for establishing oyster hatchery.hatchery.

Uninterrupted supply of food & water with low Uninterrupted supply of food & water with low silt load, and free from industrial and sewage silt load, and free from industrial and sewage pollutants is required.pollutants is required.

Sites close to river mouth are to be avoided, Sites close to river mouth are to be avoided, since during monsoon flooding dilutes sea-since during monsoon flooding dilutes sea-water salinity, rendering it unsuitable for seed water salinity, rendering it unsuitable for seed production.production.

It is advantageous to select a site which is It is advantageous to select a site which is close to the oyster farm and natural oyster close to the oyster farm and natural oyster beds.beds.

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Contd..Contd.. The site should be easily accessible for the The site should be easily accessible for the

transport of men and materials throughout the transport of men and materials throughout the year.year.

SELECTION AND CONDITIONING OF SELECTION AND CONDITIONING OF BROODSTOCK-BROODSTOCK-

The word ‘conditioning’ is used to denote the The word ‘conditioning’ is used to denote the process by which the maturation of the oyster process by which the maturation of the oyster gonad is hastened so that gametes become ripe gonad is hastened so that gametes become ripe for spawning.for spawning.

Conditioning of Oyster 5-10 below the ambient Conditioning of Oyster 5-10 below the ambient temperature with suitable algal diets temperature with suitable algal diets accelerated the gonad development, resulting in accelerated the gonad development, resulting in sexually ripe oyster.sexually ripe oyster.

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Contd..Contd.. INDUCE SPAWNING, FERTILIZATION INDUCE SPAWNING, FERTILIZATION

AND EARLY DEVELOPMENT-AND EARLY DEVELOPMENT- Fully matured bivalves can be induced to Fully matured bivalves can be induced to

spawn by giving different kinds of stimuli spawn by giving different kinds of stimuli like raising water temperature, addition of like raising water temperature, addition of sperm suspension container holding sperm suspension container holding females, mechanical stress and addition of females, mechanical stress and addition of chemicals.chemicals.

Once spawning is induced, the oyster are Once spawning is induced, the oyster are immediately transferred to separate trays immediately transferred to separate trays containing filtered seawater at ambient containing filtered seawater at ambient temperature.temperature.

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contdcontd The eggs are mostly fertilized within 60 The eggs are mostly fertilized within 60

minutes of spawning, they settle on the minutes of spawning, they settle on the tank bottom and aeration is suspended.tank bottom and aeration is suspended.

LARVAL AND NURSERY REARING-LARVAL AND NURSERY REARING- After 20hrs of fertilization, the velliger After 20hrs of fertilization, the velliger

larvae stage is reached which are stocked larvae stage is reached which are stocked at 5larvae/ml of seawater.at 5larvae/ml of seawater.

The water in the larval rearing tanks is The water in the larval rearing tanks is changed daily with fresh filtered seawater.changed daily with fresh filtered seawater.

The larvae after 18-20days attained 25-The larvae after 18-20days attained 25-30mm length and is ready for rearing in 30mm length and is ready for rearing in nursery tank.nursery tank.

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Grow-out culture Grow-out culture method-method-

Farming methods are normally grouped Farming methods are normally grouped as bottom culture and off-bottom culture.as bottom culture and off-bottom culture.

BOTTOM CULTURE-BOTTOM CULTURE- This method is low This method is low intensive for both capital and labour.intensive for both capital and labour.

A firm and stable bottom is required for A firm and stable bottom is required for culturing the oyster.culturing the oyster.

It has several disadvantages over off-It has several disadvantages over off-bottom culture including high turbidity bottom culture including high turbidity and predation.and predation.

Production is low as compared to off-Production is low as compared to off-bottom culture.bottom culture.

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Contd..Contd..OFF-BOTTOM CULTURE-OFF-BOTTOM CULTURE-Rack and string method-Rack and string method- It is also It is also

called ren method.called ren method.The racks are constructed at 1-1.25m The racks are constructed at 1-1.25m

depth.depth.Racks is a fixed structure comprising Racks is a fixed structure comprising

several wooden poles vertically driven several wooden poles vertically driven into substratum over which a wooden into substratum over which a wooden frame is made at a height of 0.5m frame is made at a height of 0.5m above the water level.above the water level.

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Contd..Contd.. The shell rings are suspended from racks.The shell rings are suspended from racks. At the end of 12months, each string may At the end of 12months, each string may

weigh 7-7.5 kg and the production of oyster is weigh 7-7.5 kg and the production of oyster is estimated at 80t/ha.estimated at 80t/ha.

RACK AND TRAY METHOD-RACK AND TRAY METHOD- The nursery reared single spat measuring The nursery reared single spat measuring

about 25mm are transferred to trays of size about 25mm are transferred to trays of size 40x40x10cm at a density of 150-200 40x40x10cm at a density of 150-200 oysterlings/tray.oysterlings/tray.

The tray is knitted with 2mm synthetic twine The tray is knitted with 2mm synthetic twine of appropriate mesh and is suspended from of appropriate mesh and is suspended from rack.rack.

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Contd..Contd.. The average growth rate of The average growth rate of oyster is 7mm/month and oyster is 7mm/month and at the end of 12months, the at the end of 12months, the oyster attains an average oyster attains an average length of 85mm.length of 85mm. STAKE CULTURE METHOD-STAKE CULTURE METHOD- The stake is driven into the substratum The stake is driven into the substratum

and one rail on the top end and two rail and one rail on the top end and two rail on the sides are fixed which hold a shell on the sides are fixed which hold a shell with spat attached.with spat attached.

The stakes are placed 60cm apart.The stakes are placed 60cm apart.

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Contd..Contd.. RAFT CULTURE METHOD-RAFT CULTURE METHOD-

Raft is the most suitable farm structure in Raft is the most suitable farm structure in sheltered bays where the depth is 5m and sheltered bays where the depth is 5m and above.above.

It is made of wooden poles placed It is made of wooden poles placed paralleled and tied across with coir rope to paralleled and tied across with coir rope to make a rigid frame.make a rigid frame.

Empty barrels of about 200l capacity are Empty barrels of about 200l capacity are tied to the underside of the raft at corners.tied to the underside of the raft at corners.

It is moored by 2 anchors and a chain. It is moored by 2 anchors and a chain.

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Contd..Contd.. LONG-LINE CULTURE METHOD-LONG-LINE CULTURE METHOD- In these system, long ropes or cables are In these system, long ropes or cables are

anchored at each end and are supported anchored at each end and are supported at intervals by floats.at intervals by floats.

Long lines of 50-100m are easy to Long lines of 50-100m are easy to manage.manage.

PROBLEMS-PROBLEMS- FOULERS-FOULERS- The major fouling organisms The major fouling organisms

in India are algae, sponges, annelids, in India are algae, sponges, annelids, bivalves and crustaceans.bivalves and crustaceans.

They compete for food and in suspended They compete for food and in suspended culture cause floatation problems.culture cause floatation problems.

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Contd..Contd.. They seriously affect seed collection by reducing They seriously affect seed collection by reducing

the surface area of the clutch.the surface area of the clutch. Can be control by application of water at high Can be control by application of water at high

pressure pumps, exposure for 1-2hour to fresh pressure pumps, exposure for 1-2hour to fresh water as oyster thrive well at wide range of water as oyster thrive well at wide range of salinity.salinity.

BORERS-BORERS- The shell of oyster is bored by certain The shell of oyster is bored by certain animals and they live within the shell making the animals and they live within the shell making the shell brittle, causing blisters on the nacre and shell brittle, causing blisters on the nacre and render the oyster an easy prey for predator.render the oyster an easy prey for predator.

Can be controlled with formalin @250-1000ppm Can be controlled with formalin @250-1000ppm is found effective for controlling worms. Chlorine is found effective for controlling worms. Chlorine can also be used.can also be used.

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Contd..Contd.. PREDATORSPREDATORS- The most common - The most common

predators found in India are crabs and predators found in India are crabs and gastropods. These predators can be gastropods. These predators can be removed by hand picking or other manual removed by hand picking or other manual practices.practices.

PARASITESPARASITES- Protozoan parasites - Protozoan parasites HaplosporidiumHaplosporidium nelsoni nelsoni are the prominent are the prominent parasites invading the oyster culture. parasites invading the oyster culture. Several work has been done and Several work has been done and genetically resistant strain has been genetically resistant strain has been developed.developed.

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Contd..Contd.. POST HARVEST HANDLING-POST HARVEST HANDLING- DEPURATION- By depuration, the DEPURATION- By depuration, the

bacterial load is reduced to a bacterial load is reduced to a permissible level and also sand and silt.permissible level and also sand and silt.

SHUCKING- The removal of oyster SHUCKING- The removal of oyster meat from the oyster is called shucking.meat from the oyster is called shucking.

PROCESSING- Frozen oyster, canned PROCESSING- Frozen oyster, canned oyster, smoked oyster, oyster stew etc.. oyster, smoked oyster, oyster stew etc..

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OYSTER IN HUMAN OYSTER IN HUMAN NUTRITIONNUTRITION

Oyster meat is easily digestible and it has Oyster meat is easily digestible and it has moderate protein content (10%), lipid (1-moderate protein content (10%), lipid (1-2%), ash (1-5%), moisture (76-80%) and is a 2%), ash (1-5%), moisture (76-80%) and is a valuable source of vitamins (A, B, B12), valuable source of vitamins (A, B, B12), amino acid (nicotinamic acid) and Minerals amino acid (nicotinamic acid) and Minerals (Ca, Fe, Na, and K).(Ca, Fe, Na, and K).

By- products and utilization-By- products and utilization- The two shelled valves constitute about The two shelled valves constitute about

85% of the total weight of oyster and 85% of the total weight of oyster and contain 52-55% calcium oxide. They are contain 52-55% calcium oxide. They are used in manufacture of calcium carbide, used in manufacture of calcium carbide, lime, fertilizers and cement.lime, fertilizers and cement.

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WORLD OYSTER WORLD OYSTER PRODUCTIONPRODUCTION

Presently 85% of the world harvest is attributed Presently 85% of the world harvest is attributed to Japan, South Korea and China.to Japan, South Korea and China.

In the early 1950’s the USA accounted for In the early 1950’s the USA accounted for nearly 60% of the world’s harvest.nearly 60% of the world’s harvest.

By 2003, global production of this species had By 2003, global production of this species had expanded to 4.38 million t. Nearly 84 percent of expanded to 4.38 million t. Nearly 84 percent of global Pacific cupped oyster production was in global Pacific cupped oyster production was in China. Two other major producers had a China. Two other major producers had a production of over 100 000 t, were Japan (261 production of over 100 000 t, were Japan (261 000 t), the Republic of Korea (238 000 t) and 000 t), the Republic of Korea (238 000 t) and France (115 000 t). The only other countries France (115 000 t). The only other countries producing more than 10 000 t in 2003 were the producing more than 10 000 t in 2003 were the United States of America (43 000 t) and Taiwan United States of America (43 000 t) and Taiwan Province of China (23 000 t)Province of China (23 000 t)

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CONCLUSION-CONCLUSION-

Although culture practices and Although culture practices and production system vary from country to production system vary from country to country, the basic principles are similar country, the basic principles are similar and the technology, infrastructure and and the technology, infrastructure and materials used are all local.materials used are all local.

Broadening of markets and Broadening of markets and technological innovations in new technological innovations in new product developmental organizations product developmental organizations can result in increased production and can result in increased production and better income opportunities to the better income opportunities to the small scale farmers.small scale farmers.

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Contd..Contd..

The limited demand for oyster meat in The limited demand for oyster meat in the domestic market is one of the major the domestic market is one of the major constraint. So, popularization of bivalves constraint. So, popularization of bivalves as an item of normal diet in a wider as an item of normal diet in a wider range of the population and effective range of the population and effective steps to encounter adverse impact on steps to encounter adverse impact on public health due to pollutants and toxic public health due to pollutants and toxic blooms may result in a better and wider blooms may result in a better and wider acceptability and honorable status for acceptability and honorable status for culture of oyster.culture of oyster.