Tag - dissolved oxygen

How does rainfall affect shrimp pond water parameters?

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Problems in shrimp farming usually occur during severe drought or heavy rainfall. Observations confim major losses occur mainly during periods of rainfall. In the last two years, we have had droughts brought about by El Niño. The US Climate Prediction Center and the International Research Institute for Climate and Society have issued an announcement that there is a 60% chance of La Niña developing in the last quarter of 2016. In contrast to El Niño, with La Niña we will [...]

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The oft-overlooked water quality parameter: pH

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Farmers are aware of the importance of monitoring levels of dissolved oxygen in their production systems and of providing supplemental aeration in intensive fish and shrimp ponds. However, other water quality parameters – as simple as they may look – are often overlooked. One such parameter is pH, which in chemistry refers to a numeric scale used to specify the acid or alkaline condition of an aqueous solutions. In a practical sense, water pH may range from 0 to 14 [...]

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Shrimp Pond Waste Management – Approaches

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Increase in food production from fisheries sector led to introduction of noval technologies and intensive farming methods in shrimp culture that result in increased production of shrimp. Management of water and waste that produced is critical factor that has to be considered. In order to discharge waste water, some improved recirculating systems have been developed. But, the sludge has been neglected and posing a serious problem. So a systematic waste management strategy is needed which include treatment, disposal and [...]

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Efficiency of mechanical aeration

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Paddlewheel design greatly impacts standard aeration efficiency Although widely implemented, the long-arm paddlewheel aerators typically used in Asia do not reflect the most efficient designs. Mechanical aerators are used increasingly in aquaculture because aeration can greatly increase the amount of production possible per unit area or volume of water. These devices usually are powered by electricity, but in some locations, small diesel engines are the power source. During a recent visit to a shrimp-farming area in Thailand, the author saw ponds aerated [...]

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Phytoplankton a crucial component of aquaculture pond ecosystems

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Proper management critical for successful production Blue-green algae will often float to the pond surface and form scums that absorb heat and can elevate water temperatures. Ponds typically contain an abundance of phytoplankton. These organisms play an important role in pond ecology and influence water quality. Although phytoplankton usually are beneficial, under some conditions, they can be quite problematic in fish and shrimp production. Phytoplanktonic algae consist of thousands of species distributed primarily among the phyla Pyrrophyta, Euglenophyta, Chlorophyta, Heterokontophyta and Cyanophyta. [...]

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Zooplankton and Phytoplankton

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Zooplankton Zooplanktons are planktonic animals that range in size from microscopic rotifers to macroscopic jellyfish. The distribution of zooplankton is governed by salinity, temperature and food availability in the environment. The smallest zooplankton can be characterized as recyclers of water-column nutrients and often are closely tied to measures of nutrient enrichment. Larger Zooplanktons are important food for forage fish species and larval stages of all fish. They also link the primary producers (phytoplankton) with larger or higher trophic-level organisms. The zooplankton community [...]

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Is It Time To Re-examine the Requirements for Shrimp Farm Certification? – Part 1

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The World Wildlife Fund suggested seven indicators – land use, water use, feed conversion ratio (FCR), survival, wild fish inclusion in feeds, dissolved oxygen in receiving waters and energy use – as a means of assessing resource use and negative environmental impacts of aquaculture production facilities. Preliminary results from a survey of shrimp farms in Vietnam and Thailand reveal that these indicators can provide an objective accounting of resource use and negative environmental impacts – including acquisition of the [...]

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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 [...]

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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 [...]

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Vibrio Control In Shrimp Farming

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Summary: Strategies to control Vibrios at aquaculture farms must revolve around limiting inputs, including those from postlarvae suppliers, those that come in with the water, those that remain in the soil between crops and those in the feed and accumulated organic matter. Adequate aeration and water exchange help reduce stressors for the culture animals. Proper pond preparation with total dryout between cycles is essential, as well. Microbial amendments are also finding widespread usage at farms. Successful Vibrio control strategies must revolve around limiting inputs, [...]

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