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GREENWATER GREENWATER WHAT IT IS Uses: fiberglass or lined, circular tank 30-52’ dia. cone bottom for daily solids removal aeration with propeller pump Produces: 3,000 – 4,000 lbs. of tilapia every 6 months HOW IT’S DONE construct tank with center sloping bottom and center cone fill with water and add fish feed daily remove solids daily check pH and adjust daily harvest after 6 months ADVANTAGES easy to stock and harvest low electricity use daily tasks are simple feed and remove solid waste DISADVANTAGES water quality is difficult to manage POND CULTURE POND CULTURE WHAT IT IS Uses: constructed ponds sloping sides and bottom drain for complete drying Produces: 4000 lbs. per acre per crop HOW IT’S DONE build pond with bulldozer fill with water stock with fish, 4000 per acre feed daily harvest completely after 6 months ADVANTAGES inexpensive to operate DISADVANTAGES reproduction by fish leads to overpopulation and stunted growth difficult to harvest CAGE CULTURE CAGE CULTURE WHAT IT IS Uses: existing watershed ponds and 1 yd 3plastic cages Produces: 400 lbs. per cage every 6 months HOW IT’S DONE build the cage with rigid plastic mesh, PVC pipe, steel hoops and floats build a demand feeder for automatic feeding stock with 300 fingerlings check feed daily harvest after 6 months. ADVANTAGES inexpensive easy to harvest DISADVANTAGES susceptible to theft AQUAPONICS AQUAPONICS WHAT IT IS Uses: fish culture integrated with hydroponic vegetable production fish are held and fed in rearing tanks separate from vegetable crop tanks Produces: 1000 lbs. of tilapia every 6 weeks HOW IT’S DONE system is constructed to design specifications fish are stocked and fed in rearing tanks water is circulated to hydroponic tanks vegetables grow on floating polystyrene sheets ADVANTAGES produces high value products multiple use or resources DISADVANTAGES expensive to construct management and labor must be highly skilled TILAPIA FINGERLING PRODUCTION TILAPIA FINGERLING PRODUCTION TILAPIA GROWOUT PRODUCTION METHODS TILAPIA GROWOUT PRODUCTION METHODS Eggs are collected from brood fish Eggs are hatched and fry are grown to 1-gram Fingerlings are grown in Recirculating or Greenwater System to 50-grams Egg Hatching Jar Brood female tilapia Day old fry are counted, stocked in a rearing tank, fed daily and grown for 1 month to 1-gram size Fry can be shipped off-island to other tilapia farmers Fingerling weight (grams) Recirculating System Greenwater System 5 5.1% 7.8% 10 4.1% 7.3% 15 3.6% 6.7% 20 3.3% 6.2% 25 3.1% 5.6% 30 2.9% 5.1% 35 2.8% 4.5% 40 2.7% 4.0% 45 2.6% 3.4% 50 2.5% 2.9% Feed Rate (% of bodyweight) for Different Sizes of Tilapia Fingerlings Nile Tilapia, 2 lbs. Red Tilapia, 1 lb. Tilapia fingerling, 50-grams Recirculating Nursery System Greenwater Nursery System