One of the main abiotic variables influencing the growth and survival of aquatic organisms is temperature. Above-thermal threshold extremes typically have a negative impact on their productivity, health, and performance. Everything in your lake or pond can be impacted by temperature. On the other hand, overly hot or cold water can harm or even kill the wildlife in your pond. The temperature is affected by several things. Sunlight, atmospheric conditions, turbidity, confluence, and man-made factors are all present. Stratification is one thing we do not want to take place. At that point, the water’s upper layer heats up while the lower layer remains cool, preventing oxygen saturation.
Effect of temperature fluctuation in aquaculture:
Since the majority of fish are ectotherms, temperature has a significant impact on their physiology. Their metabolic rate is influenced by temperature, which also has an impact on their energy balance and behavior, including eating and moving patterns. The ability and desire of fish to eat, as well as how they digest food, absorb nutrients in the gastrointestinal tract, and store surplus energy, are all influenced by temperature. Fish exhibit significant species-specific variation in their habitats, eating preferences, and physical and physiological characteristics, making the effects of temperature complex. Temperature impacts are contingent upon the rate at which temperature variations occur as well as the timing, intensity, and duration of exposure. While abrupt, short-term temperature changes may have severe, frequently harmful impacts on fish physiology, slow, long-term changes may cause acclimatization, for example, variations in metabolic and digestive enzyme profiles.
Fish sensitivity to temperature is seen in their reproduction. Rising temperatures and ‘hot waves’ that are not normal due to climate change might affect fish fertility and, in some cases, even cause sex reversals.
According to kinetic molecular theory, temperature causes water molecules to travel more swiftly because each molecule has more energy as it gets hotter. When water reaches a certain temperature, the molecules begin to travel so quickly that the hydrogen bonds holding them together begin to dissolve, turning the water into water vapor.
In warmwater, chemical reactions occur more quickly, causing fertilizers and liming material added to ponds to dissolve more quickly. As water temperature rises, the concentration of dissolved oxygen in the water at equilibrium with air falls. All aerobic species’ respiration rate rises with temperature, even if the fact that warmer water stores less oxygen at saturation than does cooler water does not immediately cause an issue. At higher temperatures, the culture species—bacteria, zooplankton, and phytoplankton—need more oxygen for respiration, yet they do so from water with lower dissolved oxygen levels. Because of this, as water temperatures rise, dissolved oxygen depletion poses a bigger risk to the welfare of aquaculture animals.
Plankton growth is enhanced by warmer temperatures because they allow for the removal of more carbon dioxide and bicarbonate from the water for use in photosynthesis. Greater pH variation between day and night results from this.
Farhana Islam
Agriculturist, Researcher
Fisheries Resource Management, CVASU
