Tag - water quality

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 [...]


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 [...]


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. [...]


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 [...]


Defining Ranges For Water Quality Variables Presents Complex, Challenging Process

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Summary: The creation and application of reference tables for acceptable concentration ranges of physical and chemical water quality variables for culture organisms would be challenging due to the differing tolerances found among the many farmed species. Factors such as water temperature, water chemistry (pH and dissolved oxygen and carbon dioxide levels), exposure time, physiological condition and size of the test animals can all affect tolerance. Especially in ponds, temperature and other water quality variables fluctuate on a daily basis, as [...]


Farming of the Pacific white shrimp, Litopenaeus vannamei in India

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Production and economics The average productivity of L. vannamei in India during 2013 is 6.49 MT/ha/year compared to 10.3 MT during 2011. Earlier, farmers were eager to stock more (60 – 80/m2), which resulted in overproduction by a fall pricing. Farmers also faced some production problems. Thus ultimately could have led the stakeholders to resort stock reducing densities that resulted in reduced productivity during 2013. The average cost of production works out around RS 190 – 200/kg for 40 count L. vannamei producing. Pond preparation The [...]


Water Composition: Dissolved Inorganic Solids

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Summary: A few anions and cations, and un-dissociated silicic acid represent the largest fraction of dissolved inorganic solids in water. The total concentration of ions is called the salinity. The total dissolved-solids concentration usually is roughly equal to salinity in freshwater. Unlike seawater, freshwater varies greatly in salinity and proportions of individual ions. Calcium and bicarbonate are dominant ions in river water, but sodium and chloride are dominant in seawater. Water contains many other inorganic substances, as well as many [...]


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 [...]


The Benefits of Shrimp Nurseries

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Over the last six years, nursery systems have evolved rapidly in Latin America.  Now, the culture period in nurseries is longer, the biomass is larger and the transfer systems and water control systems (zero exchange) are better.  Feeds and probiotics have also been improved.  The target is to produce stronger postlarvae that have been acclimated to the pond environment.  This results in better survival during the first days of culture and minimizes exposure to disease vectors. Since the causative agent [...]


Feeding Trays: Advantages and Disadvantages

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Feeding trays are typically used to avoid overfeeding in aquaculture production systems.  They are sometimes used to deliver 100% of the feed and other times to evaluate broadcast feeding efficiency with a small number of trays.  They are credited with reducing feed cost per unit of production, but there is seldom mention of their effects on overall crop profitability. Advantages of Feeding Trays • Reduced feed-conversion ratios. • Reduced feed costs. • Improved growth, frequently. • Improved water quality, which supports increased stocking density, [...]