Tag - H2S

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 [...]

9 May
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What Happens in Shrimp Ponds During Heavy Rains?

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• Water temperatures, oxygen, pH, alkalinity and salinity drop. • Phytoplankton crashes occur. • Organic material accumulates on pond bottoms. • Strong winds stir up the bottom sludge. • Toxic levels of hydrogen sulfide (H2S) are released. • Pathogenic bacteria replace beneficial bacteria. • The noise of rain pounding on the surface stresses the shrimp. • Shrimp molt because of the lower pH and phytoplankton changes. Outcomes: • Mortalities occur because of the changes in water quality, stress and pathogens. • Feed consumption drops. • Shrimp migrate to the bottom [...]

8 May
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The importance of iron in aquaculture systems

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Abundant element serves crucial role on many levels Iron is an essential element for bacteria, plants, and animals. Many enzymes important in energy transformations contain iron. Iron forms the center of the hemoglobin molecule important in oxygen transport in the blood of vertebrate and some invertebrate animals. Iron also plays an important role in photosynthesis by plants. Thus, iron plays a role in aquaculture. Iron is the fourth most abundant element in the earth’s crust, but it is present in surface [...]

8 May
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Marine Shrimp Biofloc Systems: Basic Management Practices

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This publication summarizes basic management practices for the majority of farmers raising marine shrimp (Litopenaeus vannamei) in Indiana, US, based on the most current literature available, writes Robert Rode, Purdue University. Over the past few years an increasing number of marine shrimp enterprises have started up in Indiana. These operations garner attention because of their lower capital costs, their variable scale of production, and shrimp’s high market price. Based on feedback from a 2014 meeting with Indiana shrimp farmers, it appears that both novice [...]

1 May
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“Black spot” on shrimp

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Regulations prohibit the use of many chemicals and antibiotics in U.S. shrimp aquaculture. The FDA in Silver Spring, MD publishes a list of drugs approved for aquaculture, USFDA URL: http://www.fda.gov/AnimalVeterinary/DevelopmentApprovalProcess/Aquaculture/ucm132954.htm. The main commercial operations in the U.S. claim that they use chemicals and antibiotics responsibly and only when necessary. Although unsubstantiated, this claim is reinforced by limited or no disease occurrences in recent history in the U.S., negating the need for chemical use. Agricultural lime is used to control algal blooms [...]

30 Apr
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Hydrogen Sulfide Toxic, But Manageable

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Summary: Hydrogen sulfide, which can form in pond bottom sediment, is toxic to aquatic animals because it interferes with reoxidation of cytochrome a3 in respiration. The main practices for lessening the risk of hydrogen sulfide toxicity are conservative feeding to avoid wasted feed on pond bottoms, plenty of aeration to prevent low dissolved-oxygen levels and provide a flow of oxygenated water across the soil-water interface, and liming to prevent acidic sediment and water. Claude E. Boyd, Ph.D., Department of Fisheries, and Allied [...]

25 Apr
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A farmer’s perspective on probiotics in shrimp culture

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The application and dosage of probiotics should be culture specific with more clarity and understanding provided to the farmers. For many years, the major focus of the shrimp industry in India was on the farming of the black tiger shrimp, Penaeus monodon. The economic benefits led to high stocking densities and use of spurious post larvae which in turn led to constant threat of diseases. Shrimp farmers began to use of antibiotics and water sanitizers routinely. This indiscriminate use of antibiotics brought [...]

25 Apr
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Probiotics

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Probiotics Probiotics, the natural, beneficial bacteria are now well accepted and widely used in shrimp aquaculture. Potentially, they may have one or more beneficial functions for aquaculture producers: Water and pond bottom sediment quality is improved, leading to less stress on shrimp and thus improved health. Effluent water is cleaner, thus environmental impact is low. Pathogenic bacteria and their virulence can be controlled, and the overall microbial ecosystem can be managed. Antibiotics are not used. This stops the increase in virulence and pathogenicity in [...]

25 Apr
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Better management practices for shrimp farming – Part II

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31. Water is a scarce and very precious natural resource. Try to maximize the efficiency of water utilization. 32. Exchange the water carefully. Do not frequently exchange or in-take the water. 33. During the first month, there should not be any water exchange. Starting the second month, if necessary, water exchange can be done but try to minimize it as much as possible. 34. Release the water when the plankton bloom is too thick i.e., dark green or dark brown water. 35. When [...]

23 Apr
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Better management practices for shrimp farming – Part I

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Over the past few years, better management practices or BMPs have been identified and developed on the scientific basis to protect the environment, to improve the production and economic efficiencies with shrimp farming. These BMPs are also termed as good aquaculture practices. These practices are based on broader and widely accepted international principles for sustainable shrimp farming which is jointly developed by Food and Agriculture Organization of the United Nations, Network of Aquaculture Centres in the Asia Pacific, World Bank, Worldwide Fund for Nature and United Nations Environment Programme. Here are [...]

23 Apr
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