Light penetration in water
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.
Silicon, diatoms in aquaculture
The silicon plants take up in silicic acid from water strengthens cell walls. Among the phytoplankton, diatoms particularly need silicon.
Hydrogen sulfide toxic, but manageable
Hydrogen sulfide, which can form in pond bottom sediment, is toxic to aquatic animals because it interferes with reoxidation of cytochrome a3 in respiration.
Nitrite toxicity affected by species susceptibility, environmental conditions
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.
Calcium and magnesium use in aquaculture
Aquatic plants and animals get the essential nutrients calcium and magnesium from water and food. Calcium concentrations impact the hydration and development of eggs in a hatchery, where calcium carbonate precipitation can be troublesome.
Common salt a useful tool in aquaculture, part 2
The preventive use of common salt (sodium chloride) by commercial producers of freshwater fishes has many benefits, including helping with the routine prevention of losses due to diseases, stress and mishandling during transport, harvesting, grading, counting, weighing and induced spawning.
La sal común es una herramienta útil en la acuacultura, parte 2
El uso preventivo de sal común (cloruro de sodio) por los productores comerciales de peces de agua dulce tiene muchos beneficios, incluyendo ayudar a la prevención de rutina de pérdidas debidas a las enfermedades, el estrés y el mal manejo durante el transporte, recolección, clasificación, conteo, pesaje y desove inducido.
What causes alkalinity changes in aquaculture waters?
Total alkalinity is an important variable in water for aquaculture systems, and its concentration frequently fluctuates over time in many culture systems.
Cómo la descomposición de la materia orgánica impacta los estanques acuícolas
La descomposición de la materia orgánica causa la mayoría de los problemas de calidad del agua en los estanques acuícolas. Las poblaciones bacterianas son los organismos primarios de la descomposición en un sistema acuícola, incluyendo su materia orgánica.
Factors affecting efficiency of commercial fertilizers in aquaculture
Intensification of pond aquaculture involves the use of commercial fertilizers such as urea and triple superphosphate to stimulate phytoplankton blooms. There is no objective way of determining the ideal fertilization rate for an individual pond.
Aquaculture feed composition helps define potential for water pollution
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.
Pond aeration and aerators: Second thoughts
Aerators, especially paddlewheels, are often used to mix the water and address oxygen stratification in ponds. However, most aerators do not provide the most efficient and power-conscious service. Due to thermal and oxygen stratification in ponds, the efficiency of paddlewheel aerators is low, and other present-day aerators have other problems. Emerging designs should better address effective mixing and aerating of pond water.
Atmospheric pollution affects water quality
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.
Manage pH cycles to maintain animal health
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.
Effects of mechanical aeration on evaporation rate, water temperature
This study compared water temperature and water loss by evaporation in control ponds and in ponds aerated with surface aerators at four different aeration rates. Increased aeration rate increases the evaporation rate, which in turn lowers water temperature.
Oxidants enhance water quality
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.
Efectos de la aireación mecánica sobre la tasa de evaporación, temperatura del agua
Este estudio comparó la temperatura del agua y la pérdida de agua por evaporación en estanques de control y en estanques aireados con aireadores de superficie a cuatro velocidades de aireación diferentes. El aumento de la tasa de aireación aumenta la tasa de evaporación, que a su vez reduce la temperatura del agua.
Drying, liming, other treatments disinfect pond bottoms
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.