Author
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Torrans, Eugene |
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Submitted to: Global Aquaculture Advocate
Publication Type: Trade Journal Publication Acceptance Date: 11/28/2005 Publication Date: 12/1/2005 Citation: Torrans, E.L. 2005. IMPROVED AERATION, D.O. MANAGEMENT ADVANCE CATFISH PRODUCTION. Global Aquaculture Advocate 8(6):61-63. Interpretive Summary: Maximum catfish production rates have increased ten-fold in the past forty years. This is largely due to increased aeration which allows for higher stocking and feeding rates. Our understanding of catfish oxygen requirements has increased, as has our ability to manage it. We now have efficient aerators and even automated systems to monitor the oxygen and control the aeration. Our understanding of aerator placement has increased, and production intensity is expected to increase further in the future. Liquid oxygen may even play a role in pond management. While production intensity has increased, water usage has decreased dramatically. Intensification has spared nearly 300,000 acres of bottomland from development. Technical Abstract: Aeration is arguably the single greatest factor responsible for the steady increase in catfish production rates seen in the past 40 years. Prior to emergency aeration, production rarely exceeded 1500 lbs•acre-1•year-1. Now, farmers using 2 to 3-hp/acre of electric paddlewheel aerators may see yields of 6000-12,000 lbs•acre-1•year-1, and production in individual smaller ponds may approach ten tons per acre with aeration rates up to 6-hp/acre. Research has determined that the best “operational range” for managing dissolved oxygen in catfish ponds is 1.5-2.5 mg/L. At lower concentrations production losses due to poor feed consumption are great; at higher concentrations, production stabilizes but aeration costs increase. At higher aeration intensities, automated oxygen monitoring and control systems become economical. Recent farm-scale research on aerator placement is providing new management options for oxygen management using existing equipment. Liquid oxygen (LOX) is now being used while holding catfish in a sock prior to harvest, but broader use of LOX in pond oxygen management awaits further engineering advances. Water usage, on both a per-acre and per-pound basis has dramatically decreased over the years; ponds are rarely drained and most farmers use a “6/3” water management system to conserve even rainfall. Intensification has spared nearly 300,000 acres of bottomland from pond development, providing both an environmental and recreational bonus. |
