Dry Season Survival Guideline
By Dr. Wiphada Mitbumrung, Ph.D. Applied Marine Biosciences — Wed Jun 03 2026
Dry Season Creates Multiple Stress Factors at the Same Time
The dry season is one of the most challenging periods in shrimp farming because pond conditions can change rapidly under high temperature, strong sunlight, and reduced oxygen stability. During this period, shrimp are exposed to several stress factors at once. Water temperature increases, dissolved oxygen becomes less stable, phytoplankton growth becomes harder to control, and organic waste accumulates faster. These changes create an ideal environment for Vibrio proliferation, which can weaken shrimp health and increase the risk of disease and mortality.
1. High Temperature Increases Shrimp Metabolism and Feeding Risk
One of the first effects of the dry season is the increase in water temperature. Warm water directly affects both shrimp and microorganisms in the pond. For shrimp, higher temperature increases metabolic activity. This means shrimp become more active and may show higher feeding demand. However, if feeding is not carefully controlled, farmers may easily overfeed. Uneaten feed will sink to the pond bottom and become organic waste. At the same time, shrimp feces also increase as feed intake rises. This creates a higher organic load in the pond system.
2. Warm Water and Organic Waste Favor Vibrio Growth
High temperature also favors faster bacterial growth, especially opportunistic bacteria such as Vibrio. In normal pond conditions, Vibrio may be present at low levels without causing serious problems. However, when the pond becomes rich in organic matter, Vibrio can multiply rapidly. The combination of warm water, excess feed, fecal waste, and unstable pond conditions allows Vibrio to bloom in the water column and pond bottom. Once Vibrio pressure becomes high, shrimp are more likely to experience stress, weak feeding response, poor gut condition, soft shell, and increased susceptibility to disease.
3. Strong Sunlight Can Trigger Phytoplankton Overbloom
Another major dry season risk is strong sunlight. Intense sunlight stimulates rapid phytoplankton growth, especially when excess nutrients are available from overfeeding and organic waste decomposition. At first, a dense phytoplankton bloom may look like good pond productivity. However, when phytoplankton becomes too dense, the pond becomes unstable. Overblooming phytoplankton can cause large fluctuations in dissolved oxygen and pH between day and night. During the day, phytoplankton produce oxygen through photosynthesis, but at night, they consume oxygen through respiration. In intensive ponds, this night-time oxygen demand can become very high.
4. Phytoplankton Crash Adds More Organic Waste
When phytoplankton overblooms, it can also crash suddenly. A phytoplankton crash adds a large amount of dead algal biomass into the pond. This dead plankton becomes another source of organic waste. Together with uneaten feed and feces, phytoplankton debris increases the organic load and accelerates bacterial decomposition. This process consumes oxygen and creates more favorable conditions for Vibrio growth. Therefore, strong sunlight, overfeeding, phytoplankton overbloom, and Vibrio bloom are closely connected.
5. High Temperature Reduces Dissolved Oxygen Availability
Dissolved oxygen is another critical factor during the dry season. Oxygen dissolves less efficiently in warm water. At the same time, shrimp metabolism is higher, bacterial activity is faster, and organic waste decomposition increases. This means oxygen demand becomes higher while oxygen availability becomes lower. If aeration and pond management are not sufficient, oxygen depletion can occur, especially during early morning hours. Low dissolved oxygen causes severe stress in shrimp. It reduces feeding, weakens immunity, disturbs molting, and can lead to sudden mortality, especially when combined with high Vibrio pressure.
Blue Aqua Guideline to Manage Pond during Dry Season
1. Avoid Overfeeding to Reduce Organic Load
To reduce dry season risk, feeding control is the first priority. Farmers should avoid overfeeding and adjust feed based on tray observation, shrimp behavior, water quality, and weather conditions. During very hot days or periods of low dissolved oxygen, feeding should be reduced or delayed. Feeding more because shrimp appear active can be risky if the pond cannot process the additional organic load. Good feeding management helps reduce waste accumulation and prevents unnecessary nutrient input into the pond.
2. Use FytoShade to Control Excessive Phytoplankton Growth
Phytoplankton control is also important. Strong sunlight can push phytoplankton growth beyond the stable range, especially in nutrient-rich ponds. FytoShade can be used as a smart light filter to reduce excessive sunlight penetration and help maintain a more stable phytoplankton bloom. By controlling light intensity, farmers can reduce the risk of overblooming, sudden phytoplankton crash, and extreme daily water quality fluctuations. A stable phytoplankton population helps maintain better pond balance and reduces stress on shrimp.
3. Use VibriGo to Manage Vibrio in Pond Water
Managing Vibrio in the water is another important step. VibriGo can be applied to help control Vibrio pressure in the pond environment through bioremediation and competitive exclusion. Instead of depending on antibiotics, which may disturb beneficial microbial populations, probiotic-based management supports a healthier microbial balance in the pond. Reducing Vibrio load in the water helps lower infection pressure and supports better shrimp performance during the dry season.
4. Use ViGuard*L to Protect Shrimp Gut Health
At the shrimp level, gut health should also be protected. During stressful pond conditions, Vibrio can localize in the shrimp gut and cause health problems. ViGuard can help reduce the impact of Vibrio infection in the gut and support shrimp immunity. Protecting the gut lining is important because the gut is one of the main entry points for pathogens. A healthier gut improves feed utilization, immunity, and overall resistance to environmental stress.
5. Use SoilGro to Keep Pond Bottom Clean
Finally, pond bottom cleanliness must be maintained. SoilGro can be used to help degrade organic matter and keep the pond bottom cleaner. During the dry season, organic waste accumulates faster due to overfeeding, feces, dead plankton, and high decomposition activity. If the pond bottom becomes dirty, it becomes a reservoir for harmful bacteria and toxic metabolites. Keeping organic matter low reduces oxygen demand, improves pond stability, and helps prevent Vibrio bloom.
Conclusion: Stable Pond Water Is the Key to Dry Season Survival
The dry season problem should not be viewed as only a temperature issue. It is a chain reaction. High temperature increases shrimp metabolism and feeding demand. Overfeeding increases organic waste. Strong sunlight and excess nutrients push phytoplankton to overbloom. Phytoplankton crash adds more organic debris. Organic waste decomposition consumes oxygen. Low oxygen and high temperature favor Vibrio growth. Finally, high Vibrio pressure and poor water stability make shrimp weak and increase the risk of disease and mortality. These factors do not act separately; they amplify each other and can quickly destabilize pond health. Effective dry season management requires an integrated approach: control feeding, stabilize phytoplankton, reduce Vibrio in the water, protect the shrimp gut, and keep the pond bottom clean. With proper management and the right support program using FytoShade, VibriGo, ViGuard, and SoilGro, farmers can reduce dry season stress, maintain pond stability, and lower the risk of shrimp disease and mortality.5