Even though marilculture technology for

various organisms like mussels, pearl oysters,

lobsters and crabs has been developed during

the last three decades by the CMFRI and several

other institutions in India, there has been considerable

practical difficulties for commercialising

these programmes in Indian waters due to the

rough weather conditions during the two monsoon

periods as well as due to the nonavailability

of adequate protected bays along the

Indian coasts

Achari, G P Kumaraswamy

Andrews, Joseph

Thomas, K T

CMFRI Digital Repository

< # ^ m VEIPSDF SLODIOUSSEOnCE ID THE / Mtriiiii^ ILU 'Wl MARINE FISHERIES INFORMATION SERVICE 1947-1996 ,o p. T T ^ TECHNICAL AND ^ c i t EXTENSION SERIES ^ ^ ^ -H^ijO i4 jR^^chl CENTRAL MARINE FISHERIES 3 T 5 ^ ^ T ^ ^FteTFT RESEARCH INSTITUTE <=b1PcH, ^^ TTTcT COCHIN, INDIA •HHdlil "^rfw 3TTHSTPT MRMC^ INDIAN COUNCIL OF AGRICULTURAL RESEARCH 866 SHALLOW SEA BOTTOM FARBinNG : MULTICROP SYSTEM DEVELOPED AT VIZHIN JAM * G.P. Kumaraswamy Achary, Joseph Andrews and K.T. Thomas Vtehin/om Research Centre of CMFRI. Vizhtnjam - 695 521. India Introduction Eventhough msirlculture technology for various organisms like mussels, pearl oysters, lobsters and crabs has been developed during the last three decades by the CMFRI and several other institutions in India, there has been consi-derable practical difficulties for commercialising these programmes in Indiam waters due to the rough weather conditions during the two mon-soon periods as well as due to the non-availability of adequate protected bays along the Indian coasts. Meiriculture technologies have been develoed by other countries, using floating structures like rzifts and longllne system. The rough weather condition is one of the major con-stTEiints to malnteiln such structures in our open sea. Considering these aspects the CMFRI has ini-tiated a project in May 1995 at Vizhlnjam for the development low cost technology for the farming of peeirls and mussels. Accordingly the farming procedures were oriented to utilise shallow sea bottom, £md new designs of cages which can suit to the bottom conditions were evolved so that the wave action at the surface level will not have much Impact on the animals feirmed In such cages. Design and fabrication of high density stocking cages The designs of the cages with various modifi-cations were made by the senior author. Cages of 64 X 64 cm were fabricated with four shelves to accommodate 1,000 oysters in each shelf as a unit for high density farming. The design was made In such a way that Individual unit of 64 x 64 cm was made using 10 mm M.S. rods with three supporting rods at a distance of 16 cm. The frames were covered allaround with nylon net-ting of required mesh size so that it was possible to stock oysters of different sizes at different sta-ges of farming. A total of nine frames were assem-bled into a box type cage with four inner shelves. The oysters or other bivailves stocked In the cage were then Installed at a site having favourable ecological conditions. Paper presented at the Seminar on recent development in pearl culture, grouper culture and crab farming. 6th & 7th February, 1998, Regional Centre, CMFRI Institute, Mandapam Camp, Tamil Nadu, India. 16 The cage (Fig. 1, 2, & front cover photo) has the advantage of using for farming as well as fishing simultaneously by replacing the middle Fig. 1. The pedestal cages operated at Vizhinjam with the stocked animals in high density. Fig. 2. The cages when remaining in the tilted condition (see the cages do not touch the bottom on any tilted position). shell with a lateral frame having a trap mouth to make "two-in-one" cage. (Fig. 3) Using those two-in-one cages it was possible to catch ornamental fishes, edible fishes, lobsters, mud crabs, and other marine organisms simultaneously while mussel or pearl oysters were stocked at the top and bottom shelves. These investigations are being carried out at Vizhinjam Bay near Tri-vandrum (Fig. 4 & 5). To avoid the body of the cages touching the sea bottom and to prevent its organic decay by contact with bottom silt/sediments, proper pede-Fig. 4. Lion fish Pterois sp. caught in Two-in-one cage. Fig. 3. The two-in-one cage with trapmouth for flshing-cum-farming of oyster using the top and bottom shelves. Fig. 5. Fishes caught in Two-in-one cage. stals of 120 cm height with a resting space of 70 cm^ were also fabricated using 2.5 cm M.S. rods in such a way that using two such pedestal fra-mes the cages could be kept above the sea bot-tom without touching the ground (Fig. 1). However, there are possibilities of the cages tilting towards the sides due to irregular sea bot-tom or wiih wave action. However, adequate provi-17 eiuoiNa a MAKKETINS PHARM«CEIIDC«LS POULTNT FCBO aHCLL FLESH WASTE PEANL STOCWNa rCAHLS HMIVESTliM STOCKJNC M CASES FOR FMAMIMS POST SUMERV OiSCRMTION NUCLEUS WPLANTATIOH ANAESTHESIA CLEAHWa 5 OrSTCRS FOM K - U S I M FOR WUCLEUS WPLAWTAnoy CONSTRUCTION OF RAFT FLOAT. ANCHORS.CASES HAPAS ANO SPAT COLLECTORS ARTincuu. iREEoms AND SETTLEMENT ON SPAT COLLECTORS I rAWM M 0 W I T 0 R I N 6 IN THE SE A | NUCLEArEO orsTER ftmtim NUCLEATED OrSTERFARMfNS PEARL FORMATION AM) HUSBANOPr WORKS SROWTH TO OPCRCnON SffE FRESH SETTLEMENT ON SMT COLLECTORS 8 MOMTHS--*t 1^ • HoirrHS IT  PARENT STOCK FORBREEDINS Fig. 6. Project on pearl culture (work-flow chart) slons were given by providing extra frames at the top and bottom of the cages as shown in Fig. 2. A prototype design without pedestals but with radial supporting frames was made in such away that If the cage was tilted in any angle, It did not touch the sea bottom. This design is cur-rently undergoing trials at Vizhlnjam. The designs described here are being patented. These cages have been found to be highly use-ful for fattening lobsters, crabs and fishes and also for broodstock development, In addition to the regular farming-cum-flshing by providing additional lids for feeding. It has also been obser-ved that by attaching nylon frills on the sides of the cages, these cages could act as spat collec-tors for pearl oysters and mussels and also act as fish attracting devices by providing adequate extra biomass as feed for the fishes. The cages can be operated in shallow sea bot-tom from catamarans, canoes or boats by indivi-dual fisherman or by groups of fishermen using marker nylon ropes of adequate size and floats which can also be used for attaching nylon frills for attracting spats and thus to raise natural stock of pearl oyster seeds for large scale farming. Suitable areas for farming and appropriate designs The cages can be operated in shallow sea bottom with sandy or gravelly base as well as in lagoons of Lakshadweep and Andaman Islands, shallow areas of the Gulf of Mannar and Palk Bay region. The cages can be selected according to the depth, nature of sea bottom, currents and drifts of the area where farming is proposed to be taken up. Depending on the availability of seed, the size of the farm can be decided and accor-dingly the investment can be regulated. Candidate species and farming procedure The design of the cage is versatile and almost all marine candidate organisms suitable for far-ming can be grown depending on the habitat of the species. The cages could be used for fatte-ning the Juveniles of flnfishes and shellfishes to marketable size by changing the mesh size of the cages and the feeding pattern of the cultivated species. It is also possible to grow most of the sedentary marine animals as well as free living ones using these cages. Programme for marginal farmers and large scale pearl farming The shallow sea bottom farming and the far-ming system using different types of cages presen-• ted here are relevant to multlcrop systems as well as single species crops such as peral far-ming and/or mussel farming. The general metho-dology for any crop is the same for both marginal farmers as well as large farmers or for national programmes. Different managerial systems 18 would be required for large scale adoption of pearl farming, as given in the work flow chart. a. Seed development and supply of oyster stock for implantation Since pearl oyster is the raw material for pearl culture, adequate availability of oyster stock is to be ascertained by the organising agen-cy before starting a major programme by adop-ting marginal or large scale farmers. It could be done through hatchery supply or through the supply of natural population in the natural farm. Proper training programmes for this purpose should be organised on a large scale. b. Implantation of oysters and distribution to farmers The trained persons can establish distribu-tion centres for the supply of implanted oysters to the farmers. It can be a major source of inco-me for the fishermen even without much sophisti-cated training. If each fisherman can start his own implantation centre depending on their per-sonal experience, there will be wide variations in the output and the quality of pearls. c. Husbandary work, harvest and marketing By using the high density stocking cages as well as the two-in-one cages the fishermen far-mers can collect nucleated oysters and farm them in the sea. Fouling organisms get attached on the surface of the oysters as well as on the cages and hence cleaning is essential or remove them in the case of high density stocking cages atleast once in a month. The cages are lifted, clea-ned and put back into the sea. The cleaning work can be done by the members of the family of fishermen at no additional cost. In the case of two-in-one cages since the far-mer lifts the cages daily or atleast on alternate days for the collection of ornamental fishes, edi-ble fishes, lobsters, crab etc. he can watch the intensity of fouling and attend to the cleaning work accordingly. In the tropical conditions harvest of pearl is possible within 6 to 9 months after the implanta-tion. So the farmer will have to maintain implan-ted oysters only for such a short period and the pearls can be extracted, washed in soap water and marketed directly or through an agency after sorting them into different grades. Already experi-ments have proved that the yield of high quality 'A' grade marketable pearls is 20 to 50 % and it is found that the economics of a unit system using high density stocking cages is very encouraging. d. Unit system of high density stocking cages A cage of 65 x 64 x 64 cm can hold 4,000 nucleated oysters. The details on the recurring expenses using a single cage is given in Table 1. TABLE l. Recurring expenses for shallow sea bottom Jarmtng ojpearls Part iculars Cage with pedestal Nylon ne t (2 kg) Labour charges for net t ing Nylon thread (0.5 kg) Marker rope (15 m) Float (1 no.) Nylon frill (2 kg) Cost of nucleated oysters (4,000 Nos) Labour charges for cleaning (9 months) Total Amount (Rs) 1,060 505 100 60 200 250 250 16,000 1.575 20.000 Total expense for fabricating the cage and laun-ching it in the sea is Rs. 2,425/- and the clea-ning charges for a single cage for nine spells is about Rs. 1,575/- and including the total cost of nucleated oysters at the rate of Rs. 4 / - per oyster, (Rs. 16,000/-) the total investment is Rs. 20,000/-. At the yielding rate of 25 % pearls the sale proceeds of 1,000 pearls at the rate of Rs. 50/- is Rs. 50,000/- and the net profit anticipa-ted by the fishermen is Rs. 30,000/- as shown in the operational details in Table 2. TABLE 2.Operational details for low cost shallow sea bottom farming of pearls Part iculars Cost of pedestal cage, nucleated oysters * and farming expenses (Stocking densi ty : 4 ,000 n u m b e r s . Durat ion of farming : 6-9 m o n t h s Pearls product ion @ 2 5 % : 1,000 numbers ) , Sale proceeds of 1,000 pear ls Net profit Amount (Rs.) 20,000 50,000 30.000 (* cost of 4,000 nucleated pearl oysters = Rs 16,000 Included). 19 Remarks A General picture on the scope of adopting shallow water bottom farming of pearls by margi-nal fishermen farmers as well as by large farmers through a statewlse or a national programme is dealt with in this account. We need take up this programme also for a multicrop system of farming-cum-flshing and farming-cum fattening of lobsters, crabs and fishes. The programme implementing agency has to make arrangements for seed development and supply of oysters, distri-bution of implanted oysters to the farmers and financial and technical support to the farmers for farming as well as marketing of pearls. The new designs of cages developed at Vizhinjam for shal-low water farming could cut down the Imputs on farming expenses to the minimum and it is hoped that the findings at Vizhinjam wllU enable sea bottom farming on a large scale in the seas around India and elsewhere. Acknowledgment The authors are deeply indebted to Dr. M. DevaraJ, Director, CMFRI for critically going through the manuscript and offering useful sug-gestions and for providing facilties to carry out this study at Vizhinjam and to Dr. K.K. Appukut-tan, Head, MoUuscan Fisheries Division and Dr. P.A. Thomas, for the continued support during this period of study. 20 

Shallow sea bottom farming: Multicrop system developed

at Vizhinjam

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Shallow sea bottom farming: Multicrop system developed at Vizhinjam

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