The Central Marine Fisheries Research Institute has developed techniques of oyster culture aimed at production for marketing. At present it is a semi culture depending on nature for collection of spat. Reliance on wild spat has to be reduced since it does not guarantee seed supply at all times. A plan has been evolved for hatchery production of oyster seeds. The paper describes the hatchery system being developed at Tuticorin. The layout with green house, sea water filtration, and purification and temperature control systems has been so designed as to achieve tangible resul

Easterson, D C V

Nayar, K Nagappan

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PROCEEmNGS OF THE SYMPOSIUM ON COASTAL AQUACULTURE Held at Cochin Frm Jmmry 12 to 18, 1980 PART 2 : MOLl-USCAN CULTURE (fasaed OB 31st December 1983) MARINE BIOLOGICAL ASSOCIATION OF INDIA POST BOX NO, 1023, COOHIN 682011, INDIA Prices Rs. SSfllW EDITORIAL BOASD DR. E. G. SILAS DR. R . ALAOARSWAMI DR. P . V. RAO MR. K. RENOARAJAN MR. R . NAGAPPAN NAYAR MR. S. MAHADEVAN DR. R . SATYANARAYANA RAO O MARINE BIOLOGICAL ASSOCIATION OF INDIA CocHiN-682 011, INDIA SYMPOSIUM SERIES 6 Abbreviation Proc. Symp. Coastal Aquaculture, Pt. 2 PRINTED I N INDIA BY K. G. JOHN AT THE DIOCESAN PRESS, MADRAS 7 AND PUBLISHED BY B. O. SILAS ON BEHALF OF THE MARINE BIOLOGICAL ASSOCL\TION OF INDIA, COCHIN-682 0 1 1 . Proc. Symp. Coastal Aquaculture, 1983, 2 : 513-518 A PLAN FOR MOLLUSCAN EXPERIMENTAL HArCHERY AT TUTICORIN, INDIA K. NAGAPPAN NAYAR* AND D . C. V. EASTBRSON Central Marine Fisheries Research Institute, Cochin-682108 ABSTRACT The Central Mirine Fisheries Research Institute has developed techniques of oyster culture aimed at production for marketing. At present it is a semiculture depending on nature for collection of spat. Reliance on wild spat has to be reduced since it does not guarantee seed supply at all times. A plan has been evolved for hatchery production of oyster seeds. The paper describes the hatchery system being developed at Tuticorin. The layout with green house, sea water filtration, purification and temperature control systems has been so designed as to achieve tangible results. INTRODUCTION THB CENTRAL MARINE FISHERIES RESEARCH INSTITUTE has been actively engaged in researches on pearl culture with the species Pinctadafucata (Gould) from 1972 at Tuticorin situated on the Gulf of Mannar along the southeast coast of India. In 1976 the culture of edible oyster Crassostrea madrasensis (Preston) was taken up at the centre. The pearl culture technology has been fairly well established, so also the techniques of oyster culture. The two systems rely on spat or juveniles collected from nature by diving with SCUBA for pearl oyster and setting spat collectors for edible oyster. Natural spatfalls are seasonal and erratic and the areas of spat collection also vary. An organism cannot be considered a serious candidate for large-scale culture unless the juveniles are made available economically in large numbers. This implies human control over spawning and the ability to bring high percentage of healthy larvae through the post-larval stages. A hatchery can supply healthy spat uniformly * Present address : Tuticorin Research Centre of Central Marine Fisheries Research Institute, Tuticorin, Tamil hfadu. round the year. To meet this demand, a shell-fish hatchery was designed at Tuticorin. The authors express their deep gratitude to Dr. E. G. Silas, Director, Central Marine Fisheries Research Institute for providing the necessary facilities and encouragement. Layout Plan The hatchery comprises of two green houses, two nurseries, a breeding laboratory, a nutri-tion laboratory, a phytoplankton culture room, a general laboratory and other infrastructures such as stores, air compressor room and a stand-by power generator plant (Fig. 1). The green houses are of 20 x 10.8 m each with translucent roofing of corrugated fibre-glass material with a maximum transmittance of 70% light fixed on tubular truss work. To have proper ventilation heavy duty exhaust fans have been installed. The phytoplankton culture room and the breeding-cum-larval rearing laboratory have been air-conditioned. Sea water supply Sea water is pumped from the adjoining bay. The process of collection, sedimentation, filtra-tion, ftc, has b??ii deseribed by Nayar et at, 514 K. NAGAPPAN NAYAR AND D. C. V. EASTERSON P^nTlTrrT^ Fio. 1. Hatchery building layout plan (cross section through A-A at the top). (1980). The hydrological factors of the Gulf of Mannar show a yearly bimodal cycle, due to the influence of southwest (May-June) and northeast (October-December) monsoons. The monthly mean salinity varies from 35.5 %o in March to 31.0 %o in July. Dissolved oxygen ranges frorajiA ml/1 in July to 3.1 mI/1 in March. The water is rich in oxygen during January to July and May to September (Mari-chamy and Siraimeetan, 1979 ; Easterson and Afahadevan, 1980), The sea water circulation is as given below. Only heavy duty P.V.C. conduits are being used throughout. »f4-> oeC SIM' — I>-» seOIMXTtnOH fnits • UMI <- _ . . , | L f^* I / . '<f I * mtmii'O » « A PLAN FOR EXPERIMENTAL HATCHERY FOR MOLLUSCS 515 In all the pumps used the impeller is of poly-propylene with no metals coming into contact with sea water. For the maintenance of breeders and to the nursery tanks, sea water is supplied straight from the overhead tank. To the breeding and larval tanks the water is passed through on-line sintered glass filters of numbers 1 (90-150 ^m), 2 (40-90 fim) and 4 (5-15 nm) porosity, and afterwards through a series of cartridge filters in the order of 5, 3, 1, 0.4 and -» eufltl $0oitng disc Fio. 2. The details of the cartridge filter used. 0.2 ^lm effective size retention (Fig. 2). Perio-dically filtered water is back pumped and the glass filters auto-claved. U. V. panel of similar design as stated by Shelbourne (1964) is used. The ultra-violet tubes are 30 W each and water passes through a distance of 2.5 m in each panel through a series of baflEles. Aeration An air compressor of 5 H.P. with a provision for a storage pressure tank is ;ised. The air is passed through Jobo-Fowler type of air fitters and dry, dust-free air is passed through G.I. pipes with a series of control valves. The air before being used in the larval rearing tanks is passed through on-line sintered glass filter of bacteriological grade. In addition an air pump coupled with oxygen analyser is also available to maintain dissolved oxygen at any desired level above ambient. Temperature control system Two types of temperature control systems are available. The first type can be used only to maintain temperature above the ambient. This is done using a silica-cased immersion heater in conjunction with a JUMO contact mercury thermometer and an electrical relay. Here an air pump also serves as a stirrer. This system is simple and can be installed in any type of aquarium tank. The second type has provision for both cooling and heating (Fig. 3). This embodies two units. The culture tank unit is comprised of three chambers one within the other. The outer and the middle chambers are of anodised aluminium while the innermost is of stainless steel. As required, hot or cold freshwater is circulated in between the innermost and the middle tank. The space between the middle and outer com-partments, is stuffed with glass wool for insu-lation. The JUMO contact thermometer is positioned in a comer of the stainless steel tank wherein oysters are kept. This is covered with a transparent lid to aid visual observation and the Water is stirred by means of an aerator. The necessary electrical instruments are in the second unit. It has a two-layered aluminium tank of which the inner sheet is perforated throughout and the copper cooling coil is fixed in-between. A 1000 W heating element has been fixed projecting inside the aluminium tank to avoid cooling coils coming into contact with the heater. Through an opening, freshwater can be poured inside upto' 2/3 level, so that copper coils and the heating element are always kept immersed. The aluminium tank is insu-lated. A 1/3 HP air cooled compressor similar K. NAGAPPAN NAYAR AND D. C. V. EASTERSON 516 to the one used in refrigerators is kept below. AH these are enclosed within a steel framed anodised aluminium cabinet. At the top to-wards one side a 1/20 HP water pump, relay and control switches with pilot lamps have been fixed within a metal case. The temperature is set by the JUMO contact thermometer. The pump is connected with the aluminium tank Operational plan The programme is as follows : Quarantine tanks : Sexually ripe oyster-Brushed, washed, cleaned in 3 ppm chlorine for 10 minutes-Washed out and kept in growing tanks for conditioning. Breeding tanks : Inducement of spawning by thermal stimulation-JLWO CONTACT THERMOMETER CONSOLF' ALUMINIUM TANK . COOLING COILS. HEATER. FOOT «ALVE^ ( ? 5 M P R E S S 0 R UNIT-_ _ j - p F(0. 3. Details of the temperature control system with provision for both cooling and heating. through a P.V.C. pipe and foot-valve, and With Transferred to filtered 'bacteria-free' sea the culture tank through asbestos insulated water-Releases spawn and eggs fertihzed-P.V.C. tubes, and operates in synchronisation Oysters transferred to sea. with the heating and cooling elements. The . - , * r r u r l t a n k is kept a few centtoetres above the -Larvae grown in ' bacteria-free se. wat,r instrument unit. upto eyelspot stage. A PLAN FOR EXPERIMENTAL HATCHERY FOR MOLLUSCS 517 Settling tanks : iii-Kept upto thumb nail stage Nursery: Grown— Spat collected—Transplanted to farm. The tanks used are of fibreglass. Powdered oyster shell and black coloured high density polyethylene sheets are used as spat col-lectors. Below the thumb-nail stage the spat are removed and grown in tanks wherein sea-water along with micro-algae are passed so as to upwell from the bottom. From these nursery tanks the spat are transplanted to the sea farm. Food The phytoplankters — Isochrysis galbana, Pavlova lutheri, Synechocystis salina, Chlorella ovalis, Tetraselmis gracilis and T. chui — are cultured in an airconditioned laboratory at 23° ± 2'C. Clear glass jars of 25 litre capacity are used for mass culture, Widemouth Erlen-meyer flasks of 250 ml capacity and 4 lit Halfkine culture flasks are used for subcultures. The culture flasks are illuminated with day light fluorescent strip lamps. The photoperiod is controlled by means of an automatic switch clock. Enriched Miquel's medium is used. The pH is adjusted to 7.5 — 8.0 using 1 N HCl and 1 N NaOH and the salinity is maintained at 30-32 %„ by adding boiled and cooled dis-tyied water. The composition of modified Miquel's medium is as follows : i. Miguel's fluid-A Potassium nitrate 20.2 g Distilled water 100 ml. ii. Fluid-B Di-sodium monophosphate Calcium chloride Hydrochloric acid Distilled water (sUght warming is required the salts) to 4.0 g 4.0 g 2 ml 80 ml dissolve Mineral mix Sodium salt of EDTA Ferric chloride Manganese chloride Zinc chloride Cobalt chloride Copper sulphate Boric acid Distilled water 300 mg 8mg 12 mg 1.5 mg 0.3 mg 0.12 mg 60 mg 100 ml Fig. 4. Bacteria-free alga! culture jar. 518 K. NAGAPPAN NAYAR AND D. C. V. EASTERSON iv. Vitamin mix Cyanocobalamin 0.1 mg Thiamine hydrochloride 10.0 mg Biotin 1.0 mg Distilled water 100 ml To one litre of filtered and autoclaved sea water 2 ml and 1 ml of Miquel's fluids A and B respectively are added and to this, 2 ml of mineral mix, is added and checked for pH and salinity. Later 1 ml of vitamin mix is added. Watoe's medium (Walne, 1974) is also used in the hatchery. Large scale bacteria free continuous cultures are grown in a series of 25 lit glass jars designed for the purpose (Fig. 4 a). The air filtered through a on-line sinted filter of 0.1 jita pore size is passed through the vertical tube. The air thus passed is also used to stir the culture continuously following the principle of air-lift. The side arm with a sintered filter serves as air outlet while the filter prevents any possible entry of particles. Nutrients and sea water are added through this side arm after removing the filter assembly. While removing the culture the air supply is disconnected from the vertical tube and coupled through the side arm using the unit shown in Fig. 4 b. A siphon is connected to the vertical arm. The air pressure built-up inside the flask and the siphon facili-tate the removal of culture. At a time only 3/4 of the culture is removed and the remainder is used to maintain the culture. After removing the culture fresh enriched sea water is poured and the system is operated in its grow out mode. Periodically the system needs to be sterilized. R E F E R E N C E S EASTORSON, D . C. V. AND S. MAHADEVAN 1980. Review of open sea environmental conditions along Indian Coast. In: Coastal Aquaculture: Mussel farming, Progress and Prospects. Bull. Cent. Mar, Fish., Res., Inst., 29:17-21. MARICHAMY, R. AND Pon. SIRAIMEETAN 1979. Hydro-biological studies in the coastal waters of Tuticorin, Gulf of Mannar. / . mar. biol Ass. India, 21 (1 & 2) (in press). NAYAR, K. N . , M. E . RAJAFANDIAN AND D . C. V. EASTERSON 1980. A plan for the purification of farm grown oysters before marketing. Proc. Symp. Coastal Aquaculture, MBAI, 2 ; 505-508. SHELBOURNE, J. E. 1964. The artificial propagation of marine fish. Adv. Mar. Biol, 2 : 1-8S. WALNE, P. R. 1974. Culture of bivalve moUuscs: 50 years' experience at Conway. Fishing News (Books)* Survey, England. 173 pp. 

A plan for molluscan experimental hatchery at Tuticorin, India

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A plan for molluscan experimental hatchery at Tuticorin, India

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