Responsibility
The main pond bottom soil management practices used in semi-intensive culture are pond dry-out and liming between crops. These practices accelerate organic matter decomposition, neutralize soil acidity and destroy unwanted organisms.
Responsibility
Copper is used for control of the blue-green algae responsible for off-flavors in aquaculture animals, treating diseases and parasites, and avoiding cage net fouling. Although copper is an essential nutrient for plants and animals, an excess can negatively affect the environment and human health.
Responsibility
Light penetrating water is scattered and absorbed exponentially as it passes downward. The presence of dissolved organic matter and suspended solids further impedes light penetration, and different types of solids absorb different wavelengths.
Responsibility
Acid rain typically does not heavily affect aquaculture operations, and application of agricultural limestone can buffer water against the impacts of acid rain at facilities that use stream water.
Responsibility
The amount of aeration can be increased as feeding rate increases to conserve energy. Aeration in shrimp ponds usually can be reduced from mid-morning until early evening. Research has demonstrated that considerable energy can be saved by using aerator automation systems.
Responsibility
The silicon plants take up in silicic acid from water strengthens cell walls. Among the phytoplankton, diatoms particularly need silicon.
Responsibility
Hydrogen sulfide, which can form in pond bottom sediment, is toxic to aquatic animals because it interferes with reoxidation of cytochrome a3 in respiration.
Health & Welfare
Nitrite, an intermediate compound in the oxidation of ammonia nitrogen to nitrate by nitrifying bacteria in soil and water, is considerably more toxic than nitrate. Exposure to nitrite causes gill lesions and edema in the skeletal muscles of fish, and also affects respiration.
Health & Welfare
Ammonia nitrogen occurs in aquaculture systems as a waste product of protein metabolism by aquatic animals and degradation of organic matter, or in nitrogen fertilizers. Exposure can reduce growth and increase susceptibility to diseases in aquatic species.
Responsibility
A carbon footprint is an estimate of the total carbon emissions resulting from the production, use and disposal of a product or service. Carbon footprints for aquaculture products result mainly from the use of manufactured feed and mechanical aeration.
Health & Welfare
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.
Responsibility
The reliability of trace element analyses reported by custom laboratories cannot be checked by simple techniques, and results may not always be accurate. One should check the reliability of major ion analyses by determining the charge balance and comparing the measured total ion concentration with the total ion concentration estimated from conductivity.
Health & Welfare
Farm trials compare new products or methods with practices in current use. Due to aquaculture’s inherent variability, multiple replicate treatments in experimental units that are as similar as possible are required.
Responsibility
Oxidants are used in aquaculture as disinfectants or to enhance water quality. Hydrogen peroxide and sodium carbonate peroxyhydrate can be sources of dissolved oxygen in emergency situations where mechanical aeration is not possible.
Responsibility
The traditional way of destroying organisms in pond bottoms is thorough dry-out for a week or longer. Fish toxicants and liming can kill unwanted parasites.
Responsibility
Troublesome turbidity in aquaculture pond water often results from clay or fine silt particles that remain suspended due to turbulence or sedimentation.