Freshwater Aquaculture (FAC-211)Books 1. Hand book of fisheries and aquaculture. (ICAR book by Dr. S. Ayyappan) 2. Freshwater Aquaculture (By R. K. Rath) 3. Aquaculture : Principles & Practices (By T.V.R. Pillay)
Cultivable fish species Carps, catfishes, prawns and mussels. Diverse to suit varied ecological conditions of different water bodies as also to meet the regional preferences. Technologies available for breeding and culture of air breathing (Clarias batrachus, Heteropneustes fossilis) and non airbreathing catfish (Wallago attu, Mystus seenghala, M. aor and Pungasius pungasius)
FW prawn Macrobrachium rosenbergii and M. malcolmsonii imp. For hatchery and grow out system. Culture of FW pearl through nuclei implantation in the bivalve, Lamellidens spp. Recently chinese large bivalve Hyriopsis introduced for pearl culture. Cultivation of aquatic weed makhana, Euryale ferox and water chestnut, trapa bispinosa, blue green algae spirulina spp. And biofertilizers like Azolla and duckweeds Lemna, Spirodela, Wolfia etc useful in waste tr
Coldwater aquaculture Cultivable fish species are Trout (Brown & rainbow trout), Indian trout (Schizothorax spp), Mahseer, Common carp including mirror carp among cyprinidae. Modern trout farms in India Himachal Pradesh trout farm, J & K trout farm. Mahseer breeding.
The potential cultivable species have gained importance due to excellent food value, delicious taste, better meat quality and consumer preferences.
Water resourcesPonds & tanks 2.25 million ha Beels & derelict waters 1.3 million ha Lakes & reservoirs 2.09 million ha Irrigation cannals & channels 0.12 m Km Paddy field 2.3 million ha Considering the availability of water area of ponds & tanks only 45% utilized shows the potential of horizontal expansion
Fish production FW aquaculture account over 70% of total inland fish production. Both Indian and exotic carp contribute over 90% of total freshwater aquaculture production. FFDAs enhanced the average productivity from 500 to about 2000 Kg/Ha/yr however the potential of technologies at 15 tonnes/Ha/yr.
Fish production range under different culture systemsSl. No. Culture system 1 2 3 4 5 6 7 8 9 10 11 12 Composite fish culture Intensive culture Clarias culture Sewage-fed fish Integrated fish Pen culture Cage culture Running water fish Shrimp farming Aquatic weed based Biogas slurry based Makhana & air breathing fish Average production rates (T/ha/yr) 4-6 10-15 3-5 3-5 3-5 4-5 10-15 25-50 kg/m3 2-5 3-4 3-5 1.52 + 94 kg makhana
Makhana (Euyale spp.)
Mud Crab Pen
Culture of Indian Major CarpsManagement of Nursery Ponds Pond may be either existing one or newly constructed Pond Preparation The shape of pond must be rectangular and pond direction should ne east to west. Size of pond should be 0.03 to 0.05 ha with water depth of 1 to 1.5 m. There should be screen at inlet and outlet. It is necessary to expose pond bottom to the sunlight for better mineralization, escape of toxic gases and to keep free from aquatic insects, aquatic weeds, predatory fishes. Steps (Pre-stocking) 1.Eradiation of aquatic weeds. 2.Removal of unwanted fish. 3.Application of lime. 4.Fertilization. 5.Control of aquatic insects.
1. Aquatic weedsIt is defined as unwanted and undesirable vegetation that grow in waters and if unchecked causes serious problems in fish culture. Based on the habitat, classified into floating, submerged, emergent, marginal, filamentous and algal blooms. a. Floating weeds Dont have roots, they may be floating in water with leaves over surface of water, drifted by water currents and waves induced by winds. They are more problematic than the other kind of weeds. Eg. Eichhornia (Water Hyacinth), Pistia (Water Lettuce), Salvenia (Water Fern), Duck weed (Lemna, Azolla, Spirodella) Submerged weeds Present in water column and not seen above water surface, some are rooted at the bottom of the ponds while some are non-rooted. Rooted weeds Hydrilla, Vallisneria (Tape grass), Potamogeton, Otelia, Najas, Chara (Stone wort), Non-rooted Ceratophyllum, Utricularia Emergent weed - Rooted at the pond bottom but leaves are floating above surface of water. Eg. Nymphia, Nelumbo, Nymphoides, Myriophyllum.
Marginal weeds They are grown at edge of ponds or at interphase between land and water, grow over moist land. Eg. Typha, Marselia, Cyperus. Filamentous algae and algal blooms Scum or mat forming type and found floating at pond surface. Eg. Spirogyra. Algal blooms are formed by unicellular algae. Eg. Microcystis, Euglena.They are formed due to over fertilization or due to input of excess nutrients.
Disadvantages of aquatic weeds Interference in culture activities. Decrease in DO level Restrict space for movement of fish. Utilize nutrients. Interference in netting operation. Restrict light penetration. Release toxic gases.
Strategies for developmentA balance biomass of submerged vegetation and algae is required for ecosystem of composite fish culture but excessive infestation is harmful. Control of aquatic weeds Generally the method is selected based on the dimension of the weed infestation, size of the pond and time available. 1. 2. Physical- manual or mechanical, various tools such as sickle, blades, wire mess, hooks, wooden sticks, weed cutter etc. are used. Biological- stocking of weed-eating fishes like grass carp, common carp, gourami and silver barb is an effective method for long term control and maintenance of weed population especially in grow-out. Chemical or weedicides- Marginal & emergent weeds by spraying glyphosate@3 kg/ha, foliar spray of 2-4D @ 7-10 kg/ha, phytoplankton bloom by algicide Somazine or Diuron at 0.3 to 0.5 ppm. Anhydrous ammonia @ 20ppm N is also effective not only in controlling the submerged weeds but also helps to eradicate weed & predatory fish.
Strategies for developmentYoung fish
Fish harvest from a cage
Fish feed pellets
Harvesting fish from a pond
Marine AlgaeAlgae farm
World farmed harvest in 2004 16,225,410 MT
China harvested 71% of total
Sushi with black algae wrapper Cultivated kelp
Pearl OysterInserting a nucleus
Removing a pearl
Japan is the leading producer of pearls
Strategies for development1. 2. 3. 4. 5. 6. 7. 8. 9. Application of modern aquaculture techniques. Introduction of new cultivable species. Improvement in fish feed. Improvement in the quality/availability of seed Aquaculture practices in unutilized water bodies. Increase the no. of hatcheries. Culture of prawn, aquarium fish, FW pearl production etc. should be emphasized. Improvement in the existing extension practices. Human resource development in fisheries sector (fishermen/fishfarmers, entrepreneurs etc.)
10. Improvement in the fish marketing and processing.
Soil & water characteristicsThe productivity of a fish pond depends on the physical, chemical and biological properties of the pond soil. Pond bottom acts as the laboratory where process of mineralization of organic matter takes place and nutrients are released to overlying water column. Physical properties of soil like texture and water receptivity, and chemical properties like pH, organic carbon, available nitrogen and available phosphorus are important parameters which require considerable attention for effective pond management. Slightly acidic to neutral soil with pH 6.5 to 7 is considered productive. Since low soil pH is associated with low productivity, pond bottom with low pH needs correction, done through lime application. In acid sulphate soil, the high levels of pyrite (FeS2) present in the soil remains reduced and undergo little changes as long as the soil is submerged and anaerobic. When soil is exposed , aerobic condition helps in oxidation of these pyrites resulting in formation of suphuric acid, which mixes with water in the pond and reduces its pH. Correction of soil involves, repeated drying and filling to oxidise pyrite, filling with water and holding till water pH drops to below 4 & draining of pond.
Lime requirement during soil treatmentAmount of lime required X 100KgSoil pH Ag. Lime Calcite CaCO3 Dolomite (CaMg (CO3)2 Hydrated Lime Quick lime Ca (OH)2 CaO
6.5 6.0 5.5 5.0 4.5 4.0% efficiency
2.8 5.5 8.3 11.1 13.9 16.6 90.2
2.8 5.6 8.4 11.1 13.9 16.7 89.7
2.8 5.7 8.5 11.3 14.2 17.0 88.3
4.2 8.5 12.7 17.0 21.2 25.5 58.9
2.3 4.6 6.9 9.2 11.5 13.8 108.5
Similarly alkaline pH in pond water is corrected through gypsum (CaSO4) and alum (Al2(SO4)3 . Liming is also done as a disinfecting agent in pond with neutral soil pH and for correction of water pH or control of turbidity in subsequent period of culture operations. Quick lime is preferred during pond preparation for its quick and caustic action, while calcite and dolomite are used for treatment and pH correction of pond water during culture operation.
Soil & water Quality ManagementSite characteristics like porosity, acidity, and high organic matter content of bottom soils encountered during culture operations. Drying of pond bottom to crack between crops helps in aeration, which enhances microbial decomposition of soil organic matter. The porosity of the pond bottom is corrected through bentonite, lining with plastic sheet at 0.3 to 0.5 m depth and heavy doses of organic manures (cattle dung at 10,000 to 15,000 Kg/ha/year). The water quality parameters required for optimum growth of carps are pH 7.5-8.3, temp. 27-32oC, DO more than 4 ppm, total alkalinity of 80-200mg CaCO3/L, secchi disk visibility of 25-30 cm, total inorg