Aquafeeds
Feed efficiency indicators for responsible aquaculture
While feed conversion ratios are often used as indexes of feed efficiency, they can be misleading as ecological indicators.
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Tractor-powered paddlewheels provide emergency pond aeration
Even with dedicated aerators, aquaculture farms can experience stress and mortality in culture animals due to low dissolved oxygen concentrations in pond water. Simple tractor-powered aerators offer a quick and portable solution to low dissolved oxygen levels that provides strong emergency aeration and water movement.
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Measuring water flow
Water flow within channels can be measured using the float method or calculated using rating curves that project water velocity based on a series of finite measurements.
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Estimating water volumes in aquaculture
Accurate estimations of water volumes in aquaculture systems contribute to both better management of resources and cost-efficient production.
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Groundwater and wells
Groundwater from wells is sometimes used to supply hatcheries and ponds. The potential water supply via wells is defined largely by geology.
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Copper treatments control phytoplankton
Copper sulfate is widely used as an algicide in ponds and other aquatic systems. Although copper quickly disappears from pond water, cupric ions can be harmful to aquatic animals.
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LC50 calculations help predict toxicity
LC50 – the concentration of a substance that is lethal to 50 percent of the organisms exposed to it in a toxicity test – is a useful tool because it can predict the effects of a potential toxin in aquaculture systems.
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Prevention, treatments clear muddy ponds
Water turbidity caused by suspended soil particles decreases productivity in culture ponds. Erosion control is the logical first step in correcting muddy ponds.
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Sediment microbiology, management
Sedimentation increases organic matter concentration in pond bottom soil. Particles originating from mineral soil and organic matter that do not float or dissolve settle to the bottom.
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Overview of mechanical pond aeration
Mechanical pond aerators increase the rate at which oxygen from air enters water by providing a greater surface area to facilitate diffusion.
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Feeding affects pond water quality
Feeding allows much greater production of fish and shrimp, but nutrients in feed are not converted completely to fish or shrimp flesh.
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Probiotics’ enhancement of soil, water quality examined
Probiotics used as bottom soil and water quality enhancers are primarily cultures of living bacteria, enzyme preparations, or the two combined.
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Secchi disk visibility: Correct measurement, interpretation
It would be difficult to find a pond aquaculture worker who has not measured Secchi disk visibility or at least seen someone measure it.
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Zeolite ineffective as pond treatment
Zeolite is used in industry for water softening and as media for molecular sieves but has no real benefit for aquaculture in ammonia removal.
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U.S. study finds turbidity useful In TSS, ISS estimates
Total suspended solids concentration is time-consuming to measure, but turbidity has been used to estimate TSS concentrations in some types of effluents.
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Mineral salts correct ionic imbalances in culture water
Since the application of mineral salts to correct ionic imbalances has improved survival and production, the practice is becoming increasingly common.