In aquaculture production systems, water quality is the most important factor influencing fish health and performance. What the fish want, not what we think the fish want, is referred to as good water quality. This means that we must thoroughly understand the water quality requirements of the fish in culture. Fish live in water and are completely reliant on it for all of their needs.
Water quality testing is a critical component of environmental monitoring. When water quality is poor, it has an impact not only on aquatic life but also on the surrounding ecosystem.
These sections go over all of the variables that influence water quality in the environment. These characteristics can be physical, chemical, or biological in nature. Temperature and turbidity are two physical properties of water quality. Chemical properties include variables such as pH and dissolved oxygen. Algae and phytoplankton are biological indicators of water quality.These parameters are important not only for ocean, lake, and river surface water studies, but also for groundwater and industrial processes.
Why it is important of Water Quality in Aquaculture?
Water quality monitoring can assist researchers in predicting and learning from natural environmental processes, as well as determining human impacts on an ecosystem. These measurement efforts can also help with restoration projects and ensure that environmental standards are met.
Different fish species require a unique set of water quality parameters (temperature, pH, oxygen concentration, salinity, hardness, and so on) to survive, grow, and reproduce.Each species has its own optimum range, or the range in which it performs best, within these tolerance limits. It is therefore critical for fish producers to ensure that the physical and chemical conditions of the water remain as close to the optimum range of the fish under culture as possible at all times.
Fish will exhibit poor growth, erratic behavior, and disease symptoms or parasite infestations if these optimum ranges are not met. Fish mortality may occur in extreme cases or when poor conditions persist for an extended period of time.
Pond water is made up of two major groups of substances:
· Plankton are suspended particles made up of non-living particles as well as very small plants and animals.
· Substances dissolved in water that are made up of gases, minerals, and organic compounds.
The composition of pond water changes constantly as a result of climatic and seasonal changes, as well as how a pond is used. The goal of good management is to control the composition in order to produce the best conditions for the fish. Producers must understand the physical and chemical components that contribute to good or bad water quality in order to maintain ideal pond water quality conditions.
PHYSICAL AND CHEMICAL ASPECTS OF WATER QUALITY
Temperature regulation is critical for fish welfare because it affects their behavior, feeding, growth, and reproduction. Fish metabolic rates double for every 18®F increase in temperature.
Each species has tolerance limits as well as an optimum range. When water temperatures are outside of the optimal range, fish body temperature will be either too high or too low, affecting fish growth or even causing the fish to die.
Plankton, fish wastes, uneaten feed, and clay particles suspended in water can all cause issues, particularly in recirculating aquaculture systems.Fish waste particles, which can contain up to 70% of the nitrogen load in the system and irritate the fish's gills, can be a major source of poor water quality. For every pound of fish produced, one pound of fish waste is generated.
Turbidity caused by clay or soil particles can limit light penetration and therefore photosynthesis. Sedimentation of soil particles may also suffocate fish eggs and destroy beneficial bottom organism communities such as bacteria.
Dissolved gases are those that are dissolved in water. Oxygen, carbon dioxide, nitrogen, and ammonia are the most common gases.
The most important chemical parameter in aquaculture is dissolved oxygen (DO). Low dissolved oxygen levels are directly or indirectly responsible for more fish kills than all other problems combined. Fish, like humans, require oxygen to breathe.
· Carbon Dioxide
Carbon dioxide (CO2) is commonly found in water derived from photosynthesis or from limestone bearing rock. Fish can tolerate 10 ppm concentrations if dissolved oxygen concentrations are high.
Typically, dissolved gases, particularly nitrogen, are measured in terms of "percent saturation."A gas supersaturation level of more than 110 percent is usually regarded as problematic.
As waste, fish excrete ammonia and, to a lesser extent, urea into the water. In aquaculture systems, there are two types of ammonia: ionized and un-ionized. Unionized ammonia (NH3) is extremely toxic, whereas ionized ammonia (NH4+) is not. Both forms are referred to as "total ammonia." Toxic ammonia can be degraded to harmless nitrates via biological processes.