Tag - Nitrification

High-density shrimp producer wins innovation award

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The Global Aquaculture Alliance (GAA) will recognize a farmed shrimp producer in Brazil as a leader in innovation. Camanor’s high-density, land-based facility recycles water for multiple production cycles while preventing environmental degradation and the use of chemicals or antibiotics. At GAA’s annual GOAL conference in Vancouver next week, Camanor Produtos Marinhos Ltda. Director Werner Jost will accept the Preferred Freezer Services Global Aquaculture Innovation & Leadership Award for AquaScience®, what he calls a “new concept in sustainable shrimp production” operating [...]


Testing an intensive shrimp hatchery system using biofloc technology

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The hatchery phase is a critical and complex first step in the commercial farming of Pacific white shrimp, and constant attention is required to produce shrimp postlarvae of the best quality possible. The use of biofloc technology (BFT) is increasing in the aquaculture of many commercially-important aquatic species. BFT is used to intensify production and to minimize or prevent the exchange of culture water, with a consequent reduction in potential pathogens and the discharge of nutrient-rich effluents into the environment. The [...]


Hydrogen Sulfide – The Silent Killer

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The March/April 2016 issue of AQUA CULTURE Asia Pacific, edited by Zuridah Merican (zuridah@aquaasiapac.com), contains an important article titled H2S –The Silent Killer, authored by Soraphat Panakorn (january161975@hotmail.com), a shrimp farming specialist at Novozymes Biologicals in Thailand. From Wikipedia: Hydrogen sulfide is the chemical compound with the formula H2S.  It is a toxic, colorless gas with the characteristic foul odor of rotten eggs.  It is heavier than air, very poisonous, corrosive, flammable and explosive.  Hydrogen sulfide often results from the [...]


Estimating Biofilter Size For RAS Systems

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Summary: To size a biofilter for use in a recirculating aquaculture system, the primary concern is to provide enough biofilter capacity to control total ammonia-nitrogen (TAN) concentrations to a preset limit. Also critical is specifying the maximum feed rate for the system. The lower the TAN concentration going into a biofilter, the lower the volumetric TAN conversion rate for that filter will be. Sizing decisions are best based on previous experience with a given biofilter media in a specific [...]


Aquaculture Feed Composition Helps Define Potential For Water Pollution

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Summary: A study found that feed for salmon and trout had higher organic carbon concentrations than did catfish, shrimp and tilapia feeds. Nitrogen and phosphorus concentrations were similar among salmon, trout and shrimp feeds, and higher than those in catfish and tilapia feeds. Whole body concentrations of organic carbon were greater in salmon and trout than in the other species. Salmon and shrimp had the highest whole body nitrogen concentrations. Phosphorus concentrations were greater in catfish and tilapia than [...]


Recirculating Aquaculture Technology – Part II. Starting Biofilters

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Summary: To start a biofilter together with a source of nitrifying bacteria, you must provide the conditions that will encourage the growth of the bacteria. The basic process requires initial preparation of water chemistry, adjustment of alkalinity to support bacterial growth and the addition of ammonia. Introducing nitrifying bacteria can accelerate the biofilter acclimation process. Ammonia, nitrite, pH, temperature and alkalinity levels should be monitored regularly in a standardized fashion. When starting a biofilter, it is very important to follow [...]


Recirculating Aquaculture Technology – Part I. Starting Biofilters

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Summary: Biological filtration is one of the critical required unit processes in recirculating aquaculture systems. Non-corrosive filter media with large amounts of surface provides area for nitrifying bacteria cells to colonize. “Starting” a biofilter means managing the seeding of bacteria on the media. Bacteria can be introduced with water or biofilter media from an active system, with sediment from a pond or with small numbers of “starter” animals. Commercial bacterial cultures, which shorten the starting process, are essential for [...]


Biofloc Technology: Possible Prevention For Shrimp Diseases

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Summary: Facing emerging viral problems and rising energy costs, the use of biofloc technology in biosecure systems offers an answer for sustainable shrimp aquaculture. The main attributes of biofloc systems in reducing disease risk include the fact that low water exchange improves pathogen exclusion. The aeration that keeps bioflocs suspended provides stable water quality. The diverse and stable microbial community stimulates shrimp immune systems and limits the development of opportunistic species. The suspended biofloc is also available as feed for shrimp. Highly areated biofloc shrimp culture ponds feature stable and sustainable [...]


Ammonia Addition Enhances Microbial Flocs In Nursery Phase For Pacific White Shrimp

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Summary: In a study, “pre-fertilization” in the nursery phase of a biofloc system for shrimp was tested. The objective was to accelerate the biofloc formation to minimize ammonia concentrations, avoiding high peaks during culture. This also encouraged the establishment of bacterial communities involved in the nitrifying process. The highest suspended solids concentrations occurred immediately after the pre-fertilization, demonstrating the more rapid formation of microbial aggregates with utilization of ammonium chloride. Carlos Gaona, Ph.D. Student Dariano Krummenauer, Ph.D. André Freitas Márcio Miranda, M.S. Luis Poersch, Ph.D. Wilson Wasielesky, Jr., Ph.D. Laboratório de Carcinocultura, Universidade Federal do Rio Grande, [...]


Manage pH Cycles To Maintain Animal Health

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Summary: Waters with lower pH are acidic and those of higher pH are basic. The ideal pH for most aquaculture species is between 6.0 and 8.5. Lower pH values may result in decreased growth and survival, and greater susceptibility to disease. pH typically is lowest in the early morning, increases during the afternoon and declines at night. The most accurate way to measure pH is in situ with an electronic pH meter. Claude E. Boyd, Ph.D., Department of Fisheries, and Allied Aquacultures Auburn [...]