NURSERY POND MANAGEMENT PRACTICES INTRODUCTION Nursery pond is

NURSERY POND MANAGEMENT PRACTICES

INTRODUCTION Nursery pond is a small water body which may be seasonal or perennial, but having sufficient fertility, of the soil and water for the natural production of planktonic organisms. This pond is used only for rearing in a restricted period(3 -4 days old spawn to 15 -20 days till they grow to fry stage) of fish life cycle. Earthen pond : area- 0. 02 -0. 1 ha, depth- 1. 0 -1. 5 m(tropical) 0. 5 to 1. 0 m(temperate) Concrete tank: area-50 -100 m 2 provide with soil base of 15 -20 cm

Nursery management Principle of nursery management: Nursery management is based on the principle of bringing about suitable and proper ecological, physico-chemical and biological conditions in pond, where by protection from harmful external agencies and promotion of optimum growth of fish young, will be ensured in natural conditions or through human manipulation. The various operations involved in nursery managements are directed to meet the above principle.

STEPS IN NURSERY MANAGEMENT A. Pre-stocking management 4. Eradication of predatory animals : -frogs, snakes and birds, predatory fish, weed fishes. Eradication and control of aquatic weed and algal bloom Soil correction by application of lime. Manuring and fertilization of pond. 5. Assessment of food in nurseries 6. Eradication of insects. Monitoring and measures to be taken to maintain the physico- 1. 2. 3. 7. chemical parameters of pond water.

B. Stocking management: C. Post stocking management: 1. Supplementary feeding 2. Harvesting 3. Marketing Transport to market or transfer to rearing pond for further culture.

A. Pre-stocking management 1. Eradication of predatory animals total draining of water & complete drying of nursery pond is a very easy , less expensive, and more effective to control all unwanted organisms. Eradication of predatory and weed fishes : a. mechanical and manual method: - by repeated netting and hand picking manually. b. biological c. chemical method: 1. use of fish toxicant: plant origin : - name part of plant dose duration of toxic Derrissp. (5%rotenone) root 15 -20 ppm Croton ligilium seed 30 -50 kg/ha 3 -5 days Barringtonia acutangula bark 15 -200 ppm 2 days Bassia latifolica(moc) oil cake 200 -250 ppm 12 -15 days Milletia piscidia seed 40 -50 kg/ha 5 days

Poisoning the Pond Poison the pond in case dewatering and drying is not possible. Any of the following fish toxicant may be used Bleaching powder Rotenone Powder Mohua oil cake

Common predatory and weed fish of undrainable ponds Predatory fishs Weed fishs Channa spp. Clarias batrachus Puntius spp. Oxygaster spp. Heteropneustes fossilis Pangasius pangasius Mystus spp. Ompok spp. Wallago attu Glossogobius giuris Mastocembelus spp. Amphipnous cuchia Gudusia chapra Amblypharyngodon mola Laubuca spp. Esomus danricus Osteobrama cotio

HARMFUL EFFECTS OF UNWANTED FISHES PREDATORY FISHES IF RETAINED IN THE POND will PREDATE UPON THE STOCKED FINGERLINGS

COMMON PREDATORY FISHES FOUND IN POND

Chemical toxicant: Name Dose Bleaching power(30% Cl) 500 -1000 kg/ha Urea 100 kg/ha Anhydrous ammonia 20 -25 ppm Chlorinated hydrocarbon compound (Earlier Used, Banned Now) Aldrin 0. 2 ppm Endrin 0. 001 -0. 01 ppm Deldrin 0. 01 -o. 5 ppm

IN CASE, DEWATERING OF POND IS NOT POSSIBLE THEN YOU REQUIRE ANY ONE OF THE FOLLOWING FISH TOXICANT ROTENONE

MAHUA OIL CAKE BLEACHING POWDER

WEED FISHES MULTIPLY IN THE POND IN LARGE NUMBERS AND TAKE MAJOR SHARE OF AVAILABLE FOOD THUS LEAVING ASIDE VERY LITTLE FOOD FOR CULTIVATED FISHES

REPEATED NETTING Repeated netting is suitable for only those ponds having no other fishes except carps. You can not catch predatory and weed fishes simply by netting. A few remaining of those fishes will breed and have sizable population in the pond.

2. Eradication and control of aquatic weed an algal bloom A. Manual : by dragging the weed with the help of net, long stick, rope etc. B. mechanical method: by using weed cutting boat in highly infested pond. C. biological method: stocking of weed eating fishes is a effective method , but it is a slow and steady method so it is generally not apply to nursery pond also it well effective to grow out pond.

D. chemical methods: - Floating weed control- 2, 4 D@4. 5 -6. 7 kg/ha, for Eichhornia 2, 4 D sodium salt(80%)mix with surf(0. 25%)@4 -6 kg/ha simazine@5 kg/ha generally for Hyacinth. Emergent weed control. Cu. SO 4 with ammonium sulphate for Chara. sodium arsenite@5 -6 ppm for Persistent, urea@50 ppm for Ottelia , and anhydrous ammonia @100 -150 kg/ha is effective to sub merged weed. Algal bloom: Divron@0. 1 -0. 3 ppm/ha, simazine@0. 3 -0. 5 ppm/ha.

6. Eradication of insects. Mechanical: -repeated netting, Chemical : Spraying the oil @50 lit/ha Emulsion of oil with sope with the ratio of 56: 18 Water dispersible gamacxene @0. 6 -1 ppm (Banned) Emulsion of mixture of high speed diesel(1 lt), emulsifierhyoxide 1011(0. 75 ml), water(40 ml), and it sprayed to 200 m 2 surface area of pond.

Assessment of food in nurseries: The qualitative and quantitative nature of the standing crop of plankton following fertilization of nurseries is to be ascertained at short intervals by filtering 45/50 litres of pond water through a plankton collection net made of No. 21 bolting silk.

APPLY LIME

APPLY MANURE Apply both Organic and Inorganic manure in the pond at least 6 to 7 days after liming.

3. Soil correction by application of lime: Uses of liming 1. It corrects the acidity of soil and water. 2. so, it help in to the decomposition of organic matter, and release CO 2 from bottom. 3. It rise bicarbonate content and lack of CO 2 does not become a problem. 4. It established a strong p. H buffer. It counteract the excess Mg, K, and Na ion. 5. It fix harmful acids(H 2 SO 4) 6. Lime by its toxic and caustic action , kill bacteria as well as fish parasite.

Doses of liming p. H soil condition 4 -4. 5 Highly acidic doses of lime 1000 kg/ha 4. 5 -5. 5 medium acidic 700 kg/ha 5. 5 -6. 5 slightly acidic 500 kg/ha 6. 5 -7. 5 nearly neutral 200 kg/ha

Manuring and fertilization of pond: Manuring: it should be done about 7 -15 days later of applying fish toxicant. Manuring is necessary for the production of zooplankton. Organic manure row cow dung at initial dose @15, 000 kg/ha should be applied 15 days before the stocking. Mahua oil cake should applieds@7500 kg/ha. Poultry dropping also applied@375 kg/ha Fertilization: After 2 days of liming the inorganic manure and fertilizer should be added in following rate. urea@ 50 kg/ha, and ssp@50 kg/ha.

Test for Natural Fish Food Organism Availability in the Pond • Take pond water in a glass and observe closely through. Greenish to brownish colour and the presence of actively moving small organisms are indicator of the availability of fish food organisms in the pond.

ZOOPLANKTON

B. Stocking management Proper care should be taken to release of spawn which is collected from the hatchery condition is an important factor minimizing mortality. 2. Stocking rate should be determined properly by considering primary productivity of the pond or food availability for fry. Only single species should be stock. living space available for fry in pond area generally stocking density of well prepared pond is 10 millon/ha. 1.

C. Post stocking Supplementary feeding: - management: Additional feed other than natural feed in nursery pond, which is supplied from out side with rich protein, carbohydrate, lipid , vitamin and minerals is called as supplementary feed. Vegetable item: Groundnut oil cake , rice bran, seeds, soyabean, wheat bran , oil cake etc. Animal item: Silk warm pupae, fishmeal, blood meal, dry fish, chicken viscera, etc. Common feed: -Rice bran and ground nut oil cake in 1: 1 ratio is applied@2 -3% body wt. 1.

Feeding schedule Rate of artificial feed According to Alikuhni (1957) 1 st 5 days of Double stocking weight According to Hora & Pilley (1962) the Equal to the weight 2 nd 5 days Three times the Double the weight of stocking weight 3 rd 5 days of Four times the Three times stocking weight the

2. Harvesting: -the fish fry are harvested by repeated netting with the help of fine messed dragged nets. At early morning or immediately after sun set. 3. Marketing: -when the fishes attended 25 -30 mm size it ready to harvest and market to further culture practices. The fry are well oxygenated packing is generally used for the for long way transport. and for small distance open earthen put are used.

CONCLUSION Nursery management is the back bone of the pond fish culture because it is the period of culture on which maximum mortality is observed. Survival rates in nurseries have been registered as high as 88% and an average of about 50% with size of fry ranging between 20 and 30 mm. The survivalist depend upon the food availability, ecological parameter, stocking rate, and the method of culture practice adopted for specific fish culture.

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