Oyster and mussel culture techniques

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OYSTER & MUSSEL CULTURE TECHNIQUES
Introduction:
A shellfish is any aquatic invertebrate animal having a shell and belonging to the
phylum Mollusca, the class Crustacea (phylum Arthropoda), or the phylum
Echinodermata. The term is often used for the edible species of the groups, especially
those that are fished or raised commercially.
The most commercially important shellfish are:
 Mollusk: Oyster, mussels, scallops & clamp.
 Crustacean: shrimp, prawn, lobster, crab & crayfish.
 Echinodermata: Sea urchins & sea cucumbers.
Fig: Shellfish
Importance:
 The development of new hatcheries and improvement of hatchery techniques in
existing facilities.
 Development of hatchery, nursery and grow out techniques for private
enterprises and public enhancement programs.
 Improve field grow out techniques to reduce environmental impacts.
 Reduce the effects of predation and pests in private grow out systems and public
enhancement efforts.
 The use of hatchery cultured shellfish as a means of contributing to the
effectiveness and efficiency of mitigation and restoration efforts in near shore
habitats.
 The investigations of algal nutrition with the goal of developing strains which
improve larval survival and growth.
 Estimate the cost efficiency of public enhancement programs.
Objective:
The main objective of this assignment to know about the different culture techniques
that are used for culturing of oyster & mussels.

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OYSTER CULTURE
Oyster is a mollusk with a soft un-segmented body protected by two permanent hard
shells which increase in size as the animal grows. This marine bivalve belongs to the
family Ostereidae which comprises three genera, namely: Ostrea, Crassostrea and
Pyncnodonta. There are more than 100 known species of oysters, but only several
species are widely cultivated.
Oysters are nutritious food organisms, rich in protein, minerals and vitamins. Their
importance as food has helped numerous countries culturing them, to build up foreign
exchange earnings. In Korea, for instance, oyster exports in 1982 contributed to about
54% to the total export of canned marine products to Canada, Australia, Holland and
Sweden. This is also attributed to the successful culturing of oysters in the Southern sea
area of the Korean Peninsula. The Philippines was a significant exporter of oyster to
Singapore until the early 1980's. About 180,000 kg of oyster meat valued at Peso 215
million were exported to Singapore in 1980. Foreign market for Philippine oysters
include Canada, United States, Netherlands, Switzerland, Jordan, Kuwait, Saudi Arabia,
Bahrain and Trust Territory of the Pacific Islands.
Fig: Oyster
Oyster culture is one way of producing food from the sea by farming suitable waters
and estuaries where hydrographic conditions favor oyster growth. It lends itself as a
mean of providing artisanal occupation to coastal communities either as a principal
mean of livelihood or to augment overall income. The latter is true in coastal areas
where fishing and aquaculture activities supplement each other; when the sea becomes
too rough for fishing, then the small-scale fisherman can turn to his oyster farm to be
able to meet his family needs. In addition, oyster farming, if widespread, can help ease
fishing pressure in over-fished waters as it diversifies the income sources of fishermen.
Unfortunately, however, several countries in South and Southeast Asia and the Pacific
are still engaged in experimental oyster culture and are beset by major constraints such
as lack of trained personal/experts (Bangladesh); extreme hydrographic conditions
(Burma); non-availability of local species(Fiji); low demand, lack of trained personnel,

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siltation and red-tides (Malaysia and Indonesia). Thailand is facing the problem of seed
supply and low-nutrient waters (Table 1).
TABLE 1. Status of oysterproduction inSouth and Southeast Asia and the Pacific.
Country Status Major Constraint
Bangladesh Experimental
Lack of trained personnel;
exports
Burma Experimental
Extreme hydrographic
conditions
China Highly developed Need mechanization
Fiji Experimental
No local species available for
culture
Indonesia Experimental
Low demand; lack of trained
personnel; no leasing
arrangements; red tide;
Malaysia Experimental siltation
Philippines Developed
Singapore None
Sri Lanka None
Tahiti None
Thailand Developed
Limited seed supply; low-
nutrient water;
Lack of trained personnel is identified as one major constraint in the expansion of the
oyster culture industry. For a prospective oyster culturist, the knowledge of oyster
biology as related to culture, various systems of culture and their relative efficiencies,
hydrographic conditions favoring high production, importance of pollution-free water,
local availability of brood stock/seed and health regulations relating to mollusks, are
often the keys to a successful culture operation.
Biology of oyster:
Knowledge of the biological characteristicsof the cultured oyster species, is an essential
and basic requirement for anyone intending to channel efforts and capital into this
aquaculture practice.
Anatomical features:
The oyster is a bivalve whose lower left shell is usually cupped and upper right shell
generally flat. The two shells are hinged by an elastic ligament at the umbonal or
anterior end. The hinge force tends to spring open the two valves, which is opposed by
the action of a simple adductor muscle, attached internally on each shell. The shell is
usually nacreous inside and horny outside. In addition, the oyster shell is usually fluted
when grown on a hard surface while smooth when grown in muddy bottoms. The

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salinity level also affects the structure of the shell. At high salinity values the shell is
usually quite hard while the opposite is true at low salinities.
(Fig. (A) External appearance of an oyster shell (B) internal anatomy of an oyster.)
Internally, the body of the oyster is ventrally and dorsally covered by the mantle which
secretes the shell. The mouth is located towards the umbonal end. Surrounding the
mouth are labial palps consisting of four leaf-like appendages responsible for the
selectionand rejectionof food particles. Along the ventral part of the body are the gills
composed of four long finely ridged, beige-colored appendages. On the gill surface are
hair-like structures called “cilia” which create an incoming current. The gills and cilia
are responsible for collecting food and oxygenation of the blood. The digestive system
consists of a mouth, oesophagus, stomach, crystalline style, liver and anus which are
located above the adductor muscle. The liver or digestive diverticula is a series of
branched tubes which turn light brown, black or dark green in colour depending on the
animal feeding actively. Posterior to the adductor muscle is the heart which is very
simple, consisting of one auricle and one ventricle. The nervous system is even simpler,
being made up of three nerve cells. The reproductive organs or gonads are the ovaries
in the females and testes in the males, which become greatly enlarged when fully
matured.

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Fig. Developmental stages of an oyster.
Breeding habits, larval development and setting:
Knowledge of the breeding habits, larval development and setting behavior of the oyster
is important in terms of the collection of oyster seed.
Oysters belonging to the genera Ostrea and Crassostrea are quite distinct from each
other with regard to their breeding habits. Ostrea speciesexhibit alternation of sexuality
within one spawning season. The eggs, after they have been released from the gonad,
are retained in the mantle cavity, while the sperms are extruded externally. The eggs are
fertilized by the sperms from outside and half of the larval life takes place in the shell
before they are released to the open water.
On the other hand, oysters of the genus Crassostrea change sex after one spawning
season. The sperms and eggs are released into the seawater, either all at one time or in
small amounts over a long period of time. The eggs are fertilized externally and all
subsequent developmental stages occur in the open water.
During the planktonic larval stages, the oysters are at the mercy of the environment.
Swimming is aided by the ciliated velum. As metamorphosis progresses, the oyster

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larva crawls by means of an extensible foot and explores for a suitable substratum. As
soon as it is able to locate a suitable substratum, it attaches itselfby means of the byssus
gland. Once attached, the oyster becomes a spat. Oyster larvae usually prefer clean and
hard surfaces, and this is the kind of cultch the oyster culturist should provide.
The oyster culturist should be aware that sexually mature oysters can be stimulated to
spawn by manipulating water parameters such as salinity and temperature. Rapid
changes in salinity or temperature can “tickle” sexually mature oysters to release their
gametes.
Food and feeding habits:
Oyster food consists of phytoplankton (diatoms and dinoflagellates), copepod larvae,
protozoans and detritus. In estuaries, where the hydrographic conditions are favorable,
plankton is abundant and therefore the oysters tend to perform well. During the dry
season the seawater salinity and temperature tend to increase and the oysters are found
to be thin and watery, suggesting a low supply of food.
Oysters are filter-feeders, and are considered obligatory herbivores. Adult oysters are
fixed to a hard substrate and therefore the food availability depends entirely on the
natural foodpresent in the surrounding waters. Thus, oysters completelydepend ontidal
currents for obtaining food; low current velocities and limited flushing hamper growth
and fattening.
Predators, parasites and fouling organisms:
Several organisms prey on the larvae and adult oysters.
The planktonic oyster larvae face the danger of predation from plankton-feeding
animals, including adult oysters. Adult oyster predators include fish (sting ray, bat ray,
porcupine fish, toad fish, seabream and black drum); crabs (mud crab and rock crab);
snails (conch and drill); starfish, and flatworms.
Some organisms may cause irritation problems, while other may compete for food.
Boring sponges, boring seaworms, boring molluscs, pea crabs and fouling organisms
are typical oyster pests.
Parasitism by flatworms and tapeworms in oysters has been recorded in several parts of
the world. However, they seldom cause mortality, but may interfere with growth and
reproduction.
Diseases in oysters are caused by viruses, fungus and protozoans. In Australia, large
specimens of Crassostrea commercialis have been affected by the so-called “opening
disease” or “winter mortality” during prolonged spells of high salinity, significantly
affecting the industry considering that the oysters reach marketable size in 3–4 years.
The causative organisms closely resembles the Haplosporidian, Minchinia nelsoni
which affects oysters in the United States. A mesenchymal tumor has also been found
to disturb the Pacific oysters.

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Fouling organisms can become a major problem when the oysters are permanently
submerged as in the floating culture method. Typical foulers are barnacles, mussels,
tunicates, polychaetes and hydroids. Heavy fouling may cause severe oyster mortality.
There are several ways of minimizing the disastrous effect of fouling. One is to identify
the annual fouling sequence and then culture oyster around the period, or to culture the
oysters away from fouling areas, or destroy the fouling organisms.
Fig. Natural oyster predators.
Culture:
Species cultured:
Out of 100 known oyster species, only several are widely farmed. The most widely
cultured species are Crassostrea angulata and Ostrea edulis in Europe. Other species
are C. iredalei (Philippines); C. gigas (Japan, Korea, West coast of the United States
and Canada); C. commercialis (Australia); C. brasiliana (East coast of Southern South
America); C. chilensis (West coast of South America); C. margaritacea (South Africa);
C. gasar (along the central West coast of Africa). C. gigas has been recently introduced
into France, England, Morocco, Australia and New Zealand
Site selection:
Wave/wind action:
Waters in bays and coves enjoy considerable degree of protection. Information
regarding wave and wind pattern of occurrence and intensity is usually useful to
determine whether a site is suitable or not.

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Salinity:
Oysters thrive best in brackish- and full strength seawater. Optimum range is about 17–
26 ppt (Blanco et al., 1951). Areas which are prone to flooding or surface run-offs
should be avoided.
Natural food supply:
There should be an abundant supply of phytoplankton. Plankton sampling and analysis
may serve as a good guide in determining the productivity of the area.
Availability of broodstock/seeds:
The best area, as far as this criterionis concerned, is one which has a natural population
of the species to be cultured. While oysters can be transplanted from one area to another,
procurement of broodstock or seedling is difficult and costly, especially if the distance
from the source to the farming area is great.
Pollution:
It is important that the culture area is free from any form of pollution. Areas which are
endangered by chemical, industrial or domestic effluents should be avoided. Oysters are
filter-feeders and have the capacity to absorb and accumulate heavy metals (such as
zinc, copper and mercury) and pathogenic organisms. In sitting an oyster farm, this
aspect of pollution should be seriously considered inasmuch as the lives of both oyster
and their consumers, including man, are involved.
Water depth:
Water depth should be sufficient for the selected culture method.
Post-harvest and marketing facilities:
Oysters are highly perishable, and since local demand is largely for freshor raw oysters,
marketing facilities such as roads, transportation, ice plant and cold storage should be
present.
Availability of culture materials:
Culture methods:
Gathering oysters which naturally occur in the wild is not culturing. Oyster culture
consists of gathering their seeds and growing them to marketable size. Although
techniques and methods of culture can vary from one place to another, the general
underlying principles are common to all. Spawning, larval development and provision
of food for juveniles and adults are left to nature.
Collectorsor cultches are installed on-bottom or off-bottomin order to catch the settling
larvae. Later, the seeds are transferred to the growing or fattening areas. Sometimes the

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seeds may not be transferred, in which case the seeding area also becomes the growing
and fattening area.
Culture methods are generally categorized into on-bottom and off-bottom. Each method
has its advantages and disadvantages, thus it is up to the oyster culturist to choose the
method most suitable for the selected site and his financial possibility.
Traditional Bed or Bottom Culture:
This is growing oysters directly on the bottom sub-tidally or inter-tidally. This method
requires a stable, non-shifting bottom within the correct tidal range. While bottom
culture is the simplest and cheapest, danger of mortality and stock lossdue to predation,
siltation and wave action are greatest. Harvesting is difficult. In the tropics where
potential oyster areas are largely estuaries of mud and soft bottom, bottom culture is
generally uncertain.
The method simply consists of planting the seedling directly on the bottom where they
are left to grow to the marketable size.
Fig: Bottom Culture
Disadvantages are:
o The method is limited to shallow waters with firm bottom,
o Reduced production per unit area,
o High mortality due to siltation and
o Predation and difficulty in harvesting.

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Off-bottom culture:
Where bottom conditions are not suited due to softness, wave action and tidal level,
oysters are held in suspension or off-bottom in several ways. This method can be costly,
however this is compensated by the rapid growth and high quality of the cultured
oysters.
Off-bottom culture is divided into three methods: raft, rack and stake.
Raft culture. Oysters are suspended from floating structures such as raft. Oysters maybe
held in tray or stringed. The rafts can be of any shape or material and styrofoam, oil
drums or polyethylene floats are used the float the raft.
Raft-tray:
To grow single, well-shaped oysters for a particular market such as the half-shell trade,
the tray method is used. A tray may be made of wire or plastic mesh with a wooden
frame, or entirely made of bamboo. Single oysters are laid on trays and allowed to grow
until marketable size. This culture method is costlybecause of the high investment and
high cost of maintenance.
Raft-string. Individual pieces of cultch are strung on galvanized wire, locally woven
rope, synthetic cord or monofilament nylon.
For spat collection, cultches are strung close to each other, whereas for growing or
fattening, cultches with spats are strung 8–12 inches apart. The length of the rens
depends upon the depth of water in the culture area and lifting machinery available.
Fig: Raft culture

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Rack culture:
Racks of wood, bamboo or metal, imbedded in the ground either sub-tidally or inter-
tidally, are used to hold vertically or horizontally oysters which are on trays or strings
or sticks.
This method allows control of biofouling because it permits oysters to be suspended at
a level where they may become briefly exposed during low tide. Rack culture is a low-
cost technology. Its disadvantage, however, is that it can be economical only if applied
to a maximum depth of 2–3 meters, as the cost of operation increases with increasing
depth.
The rack-string is very productive, as experienced in the Philippines. Aside from
yielding high volumes per unit area, the other advantages are: no mortality from silt,
reduced mortality from bottom crawling predators, rapid growth, ease of harvesting,
and method suitable for shallow waters.
Disadvantage:
 Costly and
 Requires a considerable supply of materials.
Fig: Oyster long-line culture method on a wooden rack.
Stake culture:
Suitable for shallow lagoons which are too shallow or too soft-bottomed for other
culture methods.

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The stakes hold oysters vertically off-bottom. The stake itself can also act as the cultch,
or some other forms of cultches, such as shells, may be impaled in or nailed to it.
Harvesting is laborious and difficult.
Harvesting & Storage:
Harvesting of oysters must be timed when oyster condition is at its best; that is when
the meat is full and creamy. Seasonal changes in oyster condition should be determined
as a guide for harvesting time.
Bottom cultured oysters can be hand-picked or dredged. Oysters in racks or rafts are
manually harvested unless the strings or trays are too heavy and require some form of
mechanization.
Oysters are best marketed immediately or briefly after harvest, however they may be
stored either wet or dry, shell-on or shucked.
Shucked oysters require cooling and safe storage temperature to arrest bacterial and
enzymatic decomposition. Shelf life is influenced by storage temperature as shown
below:
Temperature Shelf life
12 °C 3–5 days
8 °C 7–8 days
1 °C 16 days
Live oysters can also be stored dry or wet. Wet storage requires un-polluted seawater.
When dry-stored, a refrigerated room can extend storage for days or even weeks.
Sanitation measures and oyster depuration:
Oysters, wild or cultured, being filter-feeders can absorb and accumulate chemicals,
bacteria and biological toxins from the surrounding waters. Two major types of
pollution, that can affect oysters and consumers, derive from industrial activities and
sewage discharges.
Industrial effluents can be directly toxic to oysters, or can hamper their physiological
activities. Effluent particles can clog the gills and reduce the dissolved oxygen.
Direct discharge from main sewers or drainage from individual or improperly installed
septic tanks can be a severe form of pollution.
Depuration of oysters:
Shellfish depuration is based on the knowledge that filter-feeding molluscs remove
particles from the surrounding, digest some and discharge some in the form of
pseudofaeces (Quayle, 1980). The simplest and cheapest depuration for oysters is to

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transfer them from a contaminated to an uncontaminated area for 48 hours. Another
form is to place the oysters in a holding tank through which pure or purified water is
made to flows. The most expensive method is to purify oysters with chlorine, ozone or
ultraviolet light.
Shellfish marketing and consumption can be affected by dinoflagellate blooms or the
so-called “red-tides” which causes the paralytic shellfish poisoning symptoms. The
safest measure is to refrain from eating oysters during the period of red tide. Toxicity
retention can vary.
MUSSEL CULTURE
Mussels are among the many invertebrates under the Phylum Mollusca. Their wide
distribution in the coastal areas of the Indo-Pacific region makes them the most easily
gathered seafood organisms, contributing a significant percentage to the world marine
bivalve production. In the Philippines, approximately 12,000 MT of mussels were
produced in 1987. This amount consisted only of farmed green mussel, Perna viridis,
and not the brown mussels which are exclusively gathered from natural beds.
In the wild, mussels are mostly found in the littoral zone, attached in clusters on various
substrates. Being a filter-feeder of phytoplankton and detritus, it is considered the most
efficient converter of nutrients and organic matter, produced by marine organisms in
the aquatic environment, into palatable and nutritious animal protein. Its very short food
chain (one link only), sturdy nature, fast growth rate and rare occurrence of catastrophic
mass mortalities caused by parasitic micro-organisms, makes it possible to produce
large quantities at a very reasonable price (Korringa, 1976). Likewise, its ability to
attach to substrates with the byssus, makes it an ideal aquaculture speciesusing different
culture systems. According to Bardach et al. (1972), mussel culture is the most
productive form of saltwater aquaculture and its proliferation is virtually a certainty.
France can probably be credited to have the longest history of mussel culture which
dates as far back as 1235 (Bardach et al., 1972), while Spain has been reportedto be the
top world producer of farmed mussels.
Fig: Mussel

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In the Philippines, mussel culture started only in 1962 at the Binakayan Demonstration
Oyster Farm, in Binakayan, Cavite by the biologists of the then Philippine Fisheries
Commission, now Bureau of Fisheries and Aquatic Resources (BFAR). Mussels were
initially considered as a fouling organism by oyster growers. The impetus for mussel
culture in Manila Bay came about when oyster growers, attempting to collect oyster
spats in less silty offshore waters, obtained instead exceptional heavy and almost pure
mussel seedlings.
Mussel farming does not require highly sophisticated techniques compared to other
aquaculture technologies. Even un-skilled laborers, men, women, and minors can be
employed in the preparation of spat collectors as well as harvesting. Locally available
materials can be used, hence minimum capital investment is required. The mussel
harvest can be marketed locally and with good prospects for export.
Success in mussel farming, however, depends in providing some basic requirements to
the bivalve such as: reasonable amount of sheltering of the culture areas, good seawater
quality, and sufficient food in the form of planktonic organisms. These pre-requisites
are found in some coastal waters, hence locating ideal sites for mussel cultivation is
essential.
Biology of mussel:
The green mussel, Perna viridis has separate sexes, although hermaphrodism usually
occurs. Externally, it would be difficult to determine the sex, however, internally, the
gonad tissue of a sexually matured male appears creamy-white in color, while that of
the female is reddish-apricot. Sometimes young sexually immature females cannot be
distinguishable by color from male specimens.
This bivalve species reaches sexual maturity within the first year and spawns with the
rising of seawater temperature. In the Philippines, mussels spawns year-round, however
the peak period of spawning and setting is in April and May and again in September to
October. Eggs and sperms are shed separately and fertilization occurs in the water.
Mussels have two relatively distinct phases in their life-cycle. A free swimming
planktonic or larval stage and a sessile adult stage. The free swimming larvae remains
planktonic for 7–15 days depending upon the water temperature, food supply and
availability ofsettling materials. At about 2–5 weeks old, the larvae (0.25–0.3mm) seek
a suitable substrate to settle on and final metamorphosis takes place, changing its
internal organ structure to the adult form. The young spat then grow rapidly and within
4–8 weeks, after settlement, they measure 3–4 mm in shell length.
Subsequent growth of the bivalve can be distinguished into shell and body growth. The
shell length does not necessarily reflect the meat content. During spawning or food
shortage, internal energy reserves are consumed while the shell may continue to grow.
Overall growth of the mussel, as far as shell measurement is concerned is influenced by
factors like temperature, salinity, food availability, disturbances and competition for

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space. On the other hand, body growth is affected by the season which primarily relate
to sexual cycle and over-crowding to a certain extent.
Criteria for site selection:
Site location:
In prospecting sites for mussel cultivation, well-protected or sheltered coves and bays
are preferred than open un-protected areas. Sites affected by strong wind and big waves
could damage the stock and culture materials and, therefore, must be avoided. Another
important consideration is the presence of natural mussel spatfall.
Areas serving as catchment basins for excessive flood waters, during heavy rains,
should not be selected.Flood waters would instantly change the temperature and salinity
of the seawater, which is detrimental to the mussel.
Sites accessible by land or water transportation are preferred so that culture materials
and harvests can be transported easily.
Water quality:
Areas rich in plankton, usually greenish in color, should be selected. Water should be
clean and free from pollution. Sites near densely populated areas should not be selected
in order to avoid domestic pollution. In addition, the culture areas should be far from
dumping activities of industrial wastes and agricultural pesticides and herbicides.
Waters too rich in nutrients, which may cause dinoflagellate blooms and render the
mussels temporarily dangerous for human consumption, causing either gastro-intestinal
troubles or sometimes paralytic poisoning, should be avoided.
Water physio-chemical parameters are also important factors to be considered. The area
selectedshould have a water temperature ranging from 27–30°C, which is the optimum
range required for mussel growth. Water salinity of 27–35 ppt is ideal. A water current
of 17–25 cm per second during flood tide and 25–35 cm per second at ebb-tide should
be observed.
Favorable water depth for culture is 2 m and above, both for spat collection and
cultivation.
Bottom type:
Bottom consisting of a mixture of sand and mud has been observed to give better yields
of mussel than firm ones. It also provides lesseffortin driving the stakes into the bottom.
Shifting bottoms must be avoided.

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Cultured mussel species:
Among the mussels proliferating in the coastal areas of the tropical zone, the green
mussel, Perna viridis (= Mytilus smaragdinus), called tahong in the Philippines, is the
only species farmed commercially. In the temperate zone, it is the blue mussel, Mytilus
edulis, as this species can grow at low seawater temperatures.
The brown mussel, Modiolus metcalfei and M. philippinarum which form dense mats
on muddy bottoms in shallow bays (Yap, 1978) are simply gathered.
Bottom culture:
Bottom culture as the name implies is growing mussels directly on the bottom. In this
culture system a firm bottom is required with adequate tidal flow to prevent silt
deposition, removal of excreta, and to provide sufficient oxygen for the cultured
animals.
Mussel bottom culture is extensively practiced in The Netherlands, where the
production of seeds is completely left to nature. If the natural spatfall grounds are
unsatisfactory forgrowing, the seedlings are transferred by the farmer to safer and richer
ground or to his private growing plots, until the marketable size is attained. Natural
conditions controlthe quality and quantity of foodin the water flowing over the farming
plots. Marketable mussels are fished from the plots and undergo cleansing before being
sold.
This method requires a minimum investment. Disadvantages, however, of this type of
culture is the heavy predation by oyster drills, starfish, crabs, etc. Also, siltation, poor
growth and relatively low yields per unit culture area.
Fig: Mussel bottom culture.

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Intertidal and shallow water culture:
The culture methods that fall under this category are usually practiced in the intertidal
zone. The culture facilities are set in such a way that the mussels are submerged at all
times. Culture methods are:
Rack culture:
This is an off-bottom type of mussel culture. Rack culture is predominantly practiced
in the Philippines and Italy where sea bottom is usually soft and muddy, and tidal range
is narrow. The process involves setting of artificial collectors on poles or horizontal
structures built over or near natural spawning grounds of the shellfish. In the
Philippines, this is called the hanging method of mussel farming. The different
variations used are as follows:
Hanging method:
The process starts with the preparation of the spat collectors or cultches. Nylon ropes
or strings, No. 4, are threaded with coco fibre supported by bamboo pegs or empty
oyster shells at 10 cm intervals. These collectors are hung on horizontal bamboo poles
at 0.5 m apart. A piece of steel or stone is attached at the end of the rope to prevent the
collector to float to the surface. Setting of collectors is timed with the spawning season
of the mussels. Spats collected are allowed to grow on the collectors until marketabl e
size.
Other materials utilized as collectors are rubber sheets and strips from old tires.
Fig: Mussel hanging culture method

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Mussels are harvested by taking out from the water the ropes or strings and bringing
them to the shore on a banca. The same collectors canbe re-used after being cleaned of
fouling organisms. Harvested mussels are cleansed of the dirt and mud by dipping the
collectors several times in the water. The process maybe laborious, but the ease in
harvesting and availability of local materials for culture purposes makes it very
adaptable under local conditions.
Stake (tulos) method:
The stake method is midway between the rack and bottom methods. Bamboo poles, 4–
6 m in length are staked firmly at the bottom in rows, 0.5–1 m apart during low tide in
areas about 3.0 m deep and above. In areas where water current is strong, bamboo poles
are kept in place by nailing long horizontal bamboo supports between rows. Since
mussels need to be submerged at all times, it is not necessary that the tip of the poles
protrude above the low water level after staking. However, boundary poles should
extend above the high water level. In staking, enough space between plots is allowed
for the passage of the farmer's banca during maintenance.
Collected spats are allowed to grow in-situ until marketable size, 5–10 cm after 6–10
months. It has been observed, that about 2,000–3,000 seeds attach on 1 metre of stake,
1–2 m below low water level.
The mussels are harvested by pulling out the poles and bringing them ashore on a banca.
Some poles may still be sturdy and can be re-used during the next season.
Fig: Mussel stick (tulus) culture method.

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Tray culture:
Tray culture of mussels is limited to detached clusters of mussels. Bamboo or metal
trays, 1.5 m × 1 m × 15 cm sidings are used. The tray is either hang between poles of
the hanging or stake methods or suspended on four bamboo posts.
Wig-wam culture:
The wig-wam method requires a central bamboo pole serving as the pivot from which
8 full-length bamboo poles are made to radiate by firmly staking the butt ends into the
bottom and nailing the ends to the central pole, in a wigwam fashion. The stakes are
driven 1.5 m apart and 2 m away from the pivot. To further support the structure,
horizontal bamboo braces are nailed to the outside frame above the low tide mark. Spats
settle on the bamboos and are allowed to grow to the marketable size in 8–10 months.
Mussels are harvested by taking the poles out of water, or in cases that there are plenty
of undersized bivalves, marketable mussels are detached by divers.
Fig: Mussel tray culture method Fig: Mussel wig-wam culture
Rope-web culture:
The rope-web method of mussel culture was first tried in Sapian Bay, Capiz, in 1975
by a private company. It is an expensive type of culture utilizing synthetic nylon ropes,
12 mm in diameter. The ropes are made into webs tied vertically to bamboo poles. A
web consists of two parallel ropes with a length of 5 m each and positioned 2 m apart.
They are connectedto each other by a 40 m long rope tiedor fastened in a zigzag fashion
at an interval of 40 cm between knots along each of the parallel ropes. Bamboo pegs,

Page | 20
20 cm in length and 1 cm width are inserted into the rope at
40 cm interval to prevent sliding of the cropas it grows bigger.
In harvesting, the rope webs are untied and the clusters of
mussels are detached.
The method is laborious and expensive, but the durability of
the ropes which could last for several years might render it
economical on the long run. However, the effect of the culture
method on the culture ground is detrimental as gradual
shallowing of the culture area has been observed up to the
point that the areas become no longer suitable for mussel
farming.
Bouchot culture:
“Bouchot” culture is mainly undertaken in France. This
is also called the “pole culture” or stake culture. The
poles, used are big branches or trunks of oak tree, 4–6
m in length, which are staked in rows, 0.7 m apart on
soft and muddy bottoms of the intertidal zone.
Mussel seeds are collected on coco-fibre ropes which
are stretched out horizontally on poles. Young adults,
3–5 mm in size are placed in long netlon tubes (10 m in
length) and attached around the oak poles in a spiral
fashion, until marketable size.
Fig: Bouchot culture
Korringa (1976)reportedthat foran estimated length of about 600km “bouchot” netlon,
an approximate production of 7000 tons of marketable mussels yearly or an average
production of 25 kg/pole/year can be harvested.
Deep water culture:
Raft culture:
Mussel raft culture has been practiced in Spain for a long time. Mussel seeds that settle
freely on rocks or on rope collectors are suspended from a raft. When the weight of the
bivalves on a given rope exceeds a certain limit, the rope is taken out and again
distributed over a greater length until marketable size. It is a continuous thinning of the

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mussel stock to provide ample space to grow. Marketable shellfish are detached from
the rope, purified in basins before marketing.
Fig: Mussel raft culture method.
The raft may be an old wooden boat with a system of outrigger built around it. Other
kinds of rafts could be a catamaran-type boat carrying some 1000rope hangings, or just
an ordinary plain wooden raft with floats and anchors. Floats can be made of plastic,
wood, oil drums, etc. The raft are transferred from one place to another using a motor
boat.
Production of mussels from this type of culture is high. From a catamaran-type raft with
1,000 rope, 6–9 m in length, about 4,666–5,333 MT of marketable mussel can be
produced (Korringa, 1976).
Advantages of this type of culture are:
o Reduce predation,
o Utilization of planktonic food at all levels of water and
o Minimum siltation.
Long-line culture:
Long-line culture is an alternative to raft culture in areas less protected from wave
action. A long-line supported by a series of small floats joined by a cable or chain and
anchored at the bottom on both end is employed. Collected mussel spats on ropes or
strings are suspended on the line. The structure is fairly flexible.

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Mussel transplantation to new site:
Transplantation of young mussels from natural spawning grounds to sites with
favourable conditions for growth is practiced in numerous countries as mentioned
earlier. In the Philippines, however, mussel transplantation to new sites is being
encouraged to develop new areas for mussel culture, due to various reasons. Major
reasons are: rampant pollution of some existing mussel areas, urbanization growth near
mussel farms and competitive use of lands.
Mussels to be transplanted could be breeders or young adults. Important points to be
considered are: Conditions from natural spawning areas must be almost similar to the
new area, mussels on original collectors showed better survival than those detached,
and in transporting the mussel avoid being exposed to heat and freshwater.
Harvesting procedure:
Harvesters should be aware of the stress caused during the harvesting process. In
harvesting mussels special care is needed. Pulling them or using a dull scraper may tear
the byssal thread. This will result in loss of moisture after harvest or cause physical
damage causing early death of the bivalve. The right procedure is tocut the byssal thread
and leave it intact to the body. Exposure to sun, bagging and transport also increases
the stress of the mussels.
Depuration of mussels:
Depuration of mussels in the Philippines is not yet undertaken due to its prohibitive
cost. Mussel farmers cleansed their harvest by relaying them in clean water. This
procedure, however, is unlikely to reduce heavy contamination by toxic wastes,
accumulated during growing period.
Conclusion:
Shellfish are a plentiful and easily collected food source that can be found in coastal
zones as well as rivers and lakes around the world. Mussel & oyster farming has proved
viable worldwide. The economics of mussel & oyster farming are likely to be dependent
on keeping production costsdown and achieving a good market price. Therefore, before
investing any money on establishing a mussel farm, the full market potential should be
investigated. If we do this properly we should conduct a business planning exercise to
estimate the expected outlay verses returns.

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REFERENCES:
OYSTER CULTURE:
Ablan, Guillermo, L. 1949. The commercial production of oysters in the Philippines.
Bureau of Printing, Manila.
Blanco, G.J. and D.K. Villaluz. 1951. The Cultivation and Biology of Oysters in
Bacoor Bay, Luzon. Phil, Journal of Fisheries. Vol. 1.
Choi, I.H. 1983. The Korean Canning Industry. INFOFISH Marketing Digest, No. 5.
Davy, B. and M. Graham. 1982. Bivalve Culture in Asia and Pacific. In: Proceeding
of a workshop held in Singapore 16–19 February 1982.
Glude, J., Steinber, M. and R. Stevens. 1982. The feasibility of oyster and mussel
farming by municipal fisherman in the Philippines. FAO/UNDP, Manila.
Haven, D.S. and F. Perkins. 1978. Bacterial depuration by the American Oyster
(Crassostrea virginica) under controlledconditions. Institute of Marine Science,
Virginia.
Korringa, P. 1976. Farming of Cupped Oyster of the genus Crassostrea. Elsevier,
Amsterdam.
Quayle, D.B. 1980. Tropical Oysters: Culture and Methods. Ottawa, Ontario, IDRC.
Villaluz, D.K. 1939. Vertical distribution of oysters spats in Bacoor Bay. Phil. Jour.
Sci. 70.
Walne, P.R. 1974. Culture of bivalve molluscs. Fishing News Books Ltd. Farnham,
Surrey, England. 189 p.
Wilbur, K.M. and C.M. Yonge. 1965. Physiology of Mollusks. Academic Press,
New York.
Young, A. and E. Serna. 1982. Bivalve Culture in Asia and the Pacific. Proceedings
of a Workshop held in Singapore 16–19 February 1982. Brian F. Davy and Michael
Graham (eds.).
MUSSEL CULTURE:
Aypa, S.M. 1980. Factors affecting recovery and growth rate of transplanted mussels,
Perna viridis (Linneus). Master Thesis submitted to U.P.

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Bardach, J.E., J.H. Ryther, W.O. McLarney. 1972. Aquaculture: The Farming and
Husbandry of freshwater and marine organisms. Wiley-Interscience, John Willy &
Sons, Inc., New York.
Chen, F.Y. 1977. Preliminary observation on mussel culture in Singapore. ASEAN 77
FA. Eg A/ Doc. WB17.
Davy, F.B. and M. Graham. 1982. Bivalve culture in Asia and the Pacific. Proc. of a
workshop held in Singapore, Feb. 16, 1982.
Glude, J.B., M.A. Steinberg and R.C. Stevens. 1982. The feasibility of oyster and
mussel farming by municipal fishermen in the Philippines. Tech. Report, Seafarming-
Philippines. FAO/SCSP TCP/PHI/8907(1).
Jenkins, K.J. 1976. Mussel cultivation in the Marlborough Sounds (New Zealand).
N.Z. Fishing Industry Board, NZ.
Korringa, P. 1976. Economic aspects of mussel farming. Proc. FAO Tech. Conf. on
Aquaculture held in Kyoto, Japan, 26 May - 2 June 1976.
Quake, D.B. 1980. Tropical Oysters: Culture and Methods, Ottawa, Ont. IDRC.
PCARR. 1977. Philippine Recommends for oysters and mussels. PCARR, Los Banos,
Laguna.
Yap, W.G. 1978. Settlement preference of the brown mussel, Modiolus metcalfei and
its implication on the aquaculture potential of the species. Fish. Res. Jour. of the Phil.
3(1).
SEAFDEC. 1977. Third Report of the Mussel Research Project.

Oyster and mussel culture techniques

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