Field Trip to la Fish Breeding Centre and Kahandamodara Shrimp Breeding Centre

8/3/2019 Field Trip to la Fish Breeding Centre and Kahandamodara Shrimp Breeding Centre

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AQUACULTURE MANAGEMNT

FIELD OBSERVATIONS OF KAHANDAMODARA PRAWN

BREEDING CENTRE

&

MURUTHAWELA ORNAMENTAL FISH REARING CENTRE

D.D.S.Daluwatte

FS/2006/020



FIELD TRIP TO MURUTHAWELA FISH BREEDING CENTRE AND

KAHANDAMODARA SHRIMP BREEDING CENTRE

INTRODUCTION

From the history of human, fish is used as a protein source needed for the growth and the

maintenance of the body.

As same as it is used as the ornamental fish, food for animals and with the development of

the world, several industrial products are produced for the convenience with the lifestyle is

becoming in to complex.

As a result, capture fisheries was taken a higher level of development and fisheries resources

were exhausting due to the overfishing.

As a result, aquaculture and culture based fisheries has been introduced as an alternative with

regulating the fishing.

So currently aquaculture is done for many purposes in the world and it is widely spreading in

the Sri Lanka also.

In Sri Lanka, aquaculture is mainly focused to the export market while culture based fisheries

is fulfilling the needs of Sri Lankan consumers.

In there, prawns and ornamental fish are cultured with the major goal of export.

Prawn farms are widely spread in North-Western part of the island while ornamental fish

farming is doing in the many parts of the countries.

From very recent, prawn farming in Culture based fisheries is started and seed production is

done in the centers of Pambala and Kahandamodara.

In the aquaculture in the decision making process, have to consider two different portions.

Aquaculture is done with the focus of the maximum profit. So for the increase of the profit,

have to manage the production coast in least amount.

But in the other hand, fish stocks are a part of their natural habitats with relatively higher

vulnerability and for a best quality production in higher level, have to supply conditions that

the species are needed with better management of culture systems.

Aquaculture industry is continued with the management of these two basic processes.

So finally, it is needed to manage water quality, predator, disease, ammonia, weed and

maintenance of the system it the suitable way in suitable level with least cost.



MURUTHAWELA

Muruthawela, is situated near the Walasmulla town in Hambantota district and the place that

producing ornamental fish species. Before 1990’s many ornamental fish species in higher

amounts were produced and in that period, it was managed by the government. In that period

it was a one of famous carp breeding centre. After 1990’s period, it was a dark period for the

aquaculture and destruction of the aquaculture is started with the halt of government support

to the aquaculture.

After 1994 again that farm is started and management is given to the private sector. But now

management of this is not considerable level and continuing the culture to cover the expenses

only.

In management, there are 14 shareholders have invested their capital for this farm

practice. In origin, there were 25 employees and curently only 15 employees are there.

Culture

Now it is producing only mollys.

Under that,

01. Black Molly

02. White Molly

03. Marble Molly

04. Golden Molly

05. Koi Carp

06. Small amount of Shobangi

In Muruthawela, 16 ponds are situated in the nearly 60 acres area. Tanks are normally 70×70area with 3ft depth. Separate tanks for brooders and adult rearing. Pond will empty when

harvesting. Water input canal is coming from Muruthawela reservoir and outlet canal is gone

to the Urubokkaoya.



MANAGEMENT OF THE SYSTEM

01. Water Quality

From recent time, no much attention is given for water quality in the pond system. Water

may take in to the system from Muruthawela reservoir. Outlet canal send to Urubokkaoya.

In the origin of the farm, cow dug like fertilizers were used, before filling water. But

now this method is not applied.

Normally tanks are cleaned once 3-4 months.

After harvesting pond will dry normally on week.

02. Predators

Birds, frogs, snakes, otters are the predators in that culture system.

In there, have higher possibility to spread predators.

Reasons are,

Forest around the tank system

Holes and other damaged places of ponds are given places to hide to frogs and

snakes.

Surrounding bushes and large trees are given shadow to birds and otters.

To avoid the threat of the birds, they are used a net with small mesh size.

15000 fish stock is produced. But finally remains 7000 fish due to predators in Golden molly

Through this inlet, easy to enter wild Bushes and grasses are grown near ponds

Fish and other frogs and snakes.



Nets are used to control bird predators Snake as a predator, occupied near the pond

03. Food

Normally they are given foods of dry fish powder and rice ashes.

Sometimes used prima foodsMostly these fish are feed on natural foods.

Foods 4 times per day they will supply foods.

Due to the higher coast for food, two alternatives are used

01.Plankton is encourage in ponds

02. Fish food is prepare sing dry fish, prawn, rice weeds

Mostly brood stock may feed on plankton and prima food.

Manually processing food Foods available in the market

Anchovy dried fish dusts and Rice bran is 1:1 ratio mixture and mix with boiled water.

Feed balls are prepared and then it is provided for ponds. It is needed nearly 1.5 – 2 kg

of feeds per day for a tank. Further that, Irwan 681 type prima food is supplied.

04. For Disease control

Normally they are used antibiotics like tetracycline.

To prevent pathogens and other parasites, pond is dried normally one week after

harvesting.

From recent, no more attention is given for diseases due to higher labour coast and

medicine.



05. For Brooders

4 month aged Mollies fishes are considered as brooders

6×4 ft tanks are used and nearly 200-250 brooders per tank

Normally water filter system is used for brooders tank.

Mostly occur in April season

Prima food is used as the food 4 times per day for higher growth with disease control.

Fries are removed every day from the brood-stock tank and it is 200/300 fish/day

Nearly 2 years can take small fish from a one brood stock and then it is replaced by

another stock.

HARVESTING, PACKING AND MARKTING

Harvesting is done, removing the water and manually it is harvested by nets. Mollies are

harvested in the size of nearly in 3.5 cm of their size. It takes nearly 2 months to grow in

to this size. The survival rate of them is nearly 20%, and 7000-8000 fishes are finally

harvesting.

For Packing, they are used 14” of polyethene bags with aeration. In a bags, normally

packed, 150 fish if it is 3cm in size and 200 fish if it is 4cm in size.

To control diseases, Tetracycline, Methylene blue and salt mixture is added.

Fish are sold to the export companies like Ingiriya, Handapangoda, Jaela and Pannala.

They are sold for 9lkr per pair of molly.



WEEKNESS IN THE MANAGEMNT

Mainly they are not considering water quality. In an aquaculture, with relatively higher

density it is needed the water quality control and due to that, their production is decreased.

They have given up that due to higher cost.

Maintenance in the pond system is weak and newly repaired ponds also are not in standard

condition. So many damages were occurred. It is given the hidden places to predators and

reduces the production.

Grasses and bushes are grown surrounding and the land that is situated the pond and many

snakes, frogs otter like predators are appeared trough that.

In one cycle 20% of the production is destroyed due to those predators. So if they are

managing the predators, production might be more than that.

Through predator control, disease control also can achieve. So in there most important and

less coast effect thing is predator control.

If they are constructed pond in standard level with higher water quality, further increase of

the production can achieve.

But with the expenses currently, it is difficult now.

Bird control is not proper Abundant pond without better maintanance

Weak maintenance in ponds Weak maintenance in ponds



KAHANDAMODARA

Kahandamodara is situated near the Ranna town in Hambantota district. There are two state

prawn hatcheries in Sri Lanka Pambala that produce 6 million post larvae per year and

Kahandamodara that produce 10 million post larvae per year.

Prawn hatchery in Kahandamodara is built near the sea with the possibility to supply sea

water. Particularly this hatchery is built up with tsunami disaster in 2004 and job

opportunities are offered to the peasants in Kahandamodara who has been affected by

tsunami.

Hatchery is consist of

01. Artemia section

02. Brood stock tanks

03. Laboratory

04. Power Unit

Prawns are very sensitive to the changes of water quality and normally their survival rate is lower

than fishes in changes of water quality.

Brood stock is brought from outside and select only females.

Prawns are highly vulnerable for diseases. So water quality and disease control in important.

In highly intensive conditions with better condition, relatively higher production can achieve.

Within 5-6 days brooders will appear after hatching and they also are grown in intensive

system until become in to fingerlings.



01. System maintenance and water quality management

Water Salinity and the hardness are important factors.

In generally,

5ppt Salinity water for Bloodstock

12 ppt salinity for larvae

Sea water is pumping from the sea and mixed with the fresh water make water with relevant salinity

levels.

Sea water is pumped to tanks and chlorination is done to disinfect the water. Then it is kept nearly one

day to de-chlorinate. Chlorine level is checked by the colouri-method using Ortho tholudeen

chemical as indicator

Chlorine is represented by yellow colour and need more dechlorination.

Then it is mixed with the fresh water and it is come from ressing filter to mix each other.

C1V1= C2V2 formula is used to make water to another salinity level from one salinity level

Then send through 10 µm mesh filter and after that 5 µm meshed cartridge filter.

Water is passed through UV filters for further disinfection.

Refractometer is used to measure salinity. DO is maintained in 5-7ppm with 24 h aeration.

Stocking and mixing water Pumping system



02. Disease Control

Prawn is highly vulnerable for diseases. So in a hatchery, with high stocking density

and artificial environment, disease control is impotent.

Mainly they are washed and wear boots when entering to the hatchery.

KMnO4 is used to bath the hatchery

All water may chlorinated and disinfect

Aeration is constantly given to the hatchery.

03. Feeding

Artemia feeding is given to brooders till stage 5. Here red type artemia is needed

because saltern artemia is large in size and impossible to ingest. To produce artemia,

separated artemia section is also maintained. Feeding is done 5.00 am, 11.30 am, 5.30

p.m and size above than Post larvae stage 5 are fed only one time per day by egg yolk. It is

about 11.00 am.

Egg Yolk feed is given to larvae.

Artemia culture

Artemia cysts are used to produce artemia. It is needed 24 hours for hatching.

Perfect 100% oxygen aeration is given in 24hours.

Sunlight is given through transparent sheet on the roof and at the night time

3000 W of bulb is used.

36ppt salinity water is needed and it is kpt in 2g /L of Artemia cyst of stocking

density.

After the hatching aeration is stopped and light is supplied in 20 minutes.

Then release through the output valve and washed with sea water using

300µm mesh size net.

1g of Artemia is 9 lkr and 120 artemis for 1 cycle 1500000lkr / month

Commercially available

Artemia eggs

Artemia food production



Egg yolk feed

Used, eggs, Non fat milk powder, PL feed (Red top) , Corn flake with the ratio

of

10: 16 spoon: 16 spoons: 16 spoons

Above mixture is mixed with Cod liver oil and blended and after that steam

cooking.

Then it is sieved through several sieve plates separating food particles for

different stages.

500 µm sieve size for 5 to 7 stage of Post Larvae, 710 µm sieve size for 8 and

9 stage of Post Larvae and 1000 µm sieve size for more than that.

4 Brood stock maintenance

Separate tanks are used to keep brood stock.

First quarantine tanks containing 10 ppt of formalin are used for disinfection and in it,

they ar kept in 10 minutes.

Then they introduced to the Brooder tanks with 5ppt salinity.

200 prawn brooders are kept in a 5 t tank.

produced approximately 5 lacks of larvae.



Production

Finally 5000000 stock may harvest once with this conditions.

They are normally stock in 60-70 /L fry stock with aeration

They are converted in to fresh water prawns putting in to different salinity levels gradually

before packing.

They are kept gradually 12ppt, 9 ppt, 5 ppt, 0 ppt salinity levels in day by day.

Large amount of prawns may have due to this proper management system.

When comparing Kahandamodara and Muruthawela,

In Kahandamodara, they are highly concern of water quality and as a result, mortality is

relatively lower and relatively larger harvest is received.

And in Kahandamodara, they are given properly prepared foods with essential nutrition. So

highly vulnerable prawns like species can be maintained with relatively lower mortality.

But in Muruthawela, they can easily control the predators. Through that, diseases also maycontrol. But production is reduced due to carelessness of this predator avoidance.

Due to that higher intensity, in Kahandamodara could produce more prawn fries in higher

stock density.

Documents

Field Trip to la Fish Breeding Centre and Kahandamodara Shrimp Breeding Centre