According to the latest forecast from the meteorological department, a strong cold front is about to hit. Within the next 72 hours, the temperature in many places will drop sharply by 8 to 12 degrees Celsius, with some areas experiencing strong winds, rain and snow. This time, the temperature drop is rapid, significant and lasts for a long time, which will pose a serious threat to aquaculture!
How to precisely prevent and control? Make preparations for these three stages
I. 48 hours before the temperature drop (Critical preparation period)
1. Double insurance of facility reinforcement and insulation
Greenhouse breeding: Check that the greenhouse film is undamaged, reinforce it with a film-pressing rope, add a non-woven fabric inner insulation layer inside the greenhouse, and set up a windproof curtain at the entrance. To the north of the open-air pool, piles of straw stalks or colorful tarpaulins are driven up to prevent the cold wind from blowing directly onto the water surface.
Pipe anti-freezing: Wrap the inlet and outlet water pipes and aerator pipelines with thermal insulation cotton, and apply anti-rust oil to exposed metal parts. Drain the water from the unused water pipes and install insulating straw on the ones in operation.
Equipment maintenance: Trial operation of the aeration machine (impeller type + aeration type) and the backup generator for more than 30 minutes to ensure sufficient fuel/engine oil. Stock up on 1-2 portable aeration pumps for emergency use.
2. Water body and fish and shrimp constitution adjustment
Deepen the water level: Immediately add fresh water to raise the water level in the pond by 30-50cm, and keep the final water depth at 1.8-2.5 meters (for every additional meter of water depth, the water temperature fluctuation decreases by 0.5-1℃).
Anti-stress pretreatment: Sprinkle vitamin C (200-300g/mu) + glucose (1-2kg/mu) throughout the pond, and add immune polysaccharides to the feed to enhance the cold resistance of fish and shrimp.
Stop feeding + bottom improvement: Stop feeding one day before the temperature drops (the digestive enzyme activity of fish decreases at low temperatures to prevent enteritis). Sprinkle potassium peroxymonosulfate complex salt (500g per mu) throughout the pond to improve the bottom and reduce the risk of bottom return.
Ii. 72 hours during the cooling Period (Core Defense Period)
Real-time monitoring + uninterrupted oxygenation
Record the water temperature (to avoid a sudden drop of more than 2℃ in a single day) and dissolved oxygen (≥5mg/L) every 2 hours. Start the aerator immediately if the values fall below the warning values.
Unfrozen ponds: Turn on the aeration machine in the second half of the night until dawn. Frozen pond: Keep the machine running intermittently for 1-2 hours during the day, and at the same time, manually chisel the ice (leaving 1-2 ventilation holes per 100 square meters) to prevent oxygen deficiency.
Greenhouse breeding: At night, use smokeless heaters to increase the temperature (keep away from flammable materials), and control the temperature inside the greenhouse to not be lower than 5℃. Clear the snow on the roof of the shed in time to prevent collapse.
2. Anti-freezing + Do not operate blindly
Lay foam boards (spaced 50cm apart) or straw curtains on the water surface to reduce heat loss. Avoid pulling the net, cleaning the pool, or conducting large-scale drainage and replacement (to prevent sudden changes in water temperature from increasing stress).
Warm-loving species (tilapia, white shrimp) : When the water temperature drops below 13-15℃, they should be caught and put on the market in time to avoid large-scale deaths.
3. Emergency disease prevention and control
If fish or shrimp are found to have scratches, immediately apply povidone-iodine (500ml per mu) throughout the pond to prevent water mold disease.
Signs of water mold disease have emerged: Apply compound metalaxyl powder throughout the pond and use an aerator for continuous aeration to maintain high dissolved oxygen in the water.
Iii. 7 days after the temperature drop (to reduce secondary losses)
1. Water quality + facility repair
Test water quality indicators: ammonia nitrogen ≤0.2mg/L, nitrite ≤0.1mg/ L. If the standards are exceeded, sprinkle zeolite powder (10-20kg/mu) to adsorb harmful substances.
Restore water body ecology: After disinfection for 3 days, sprinkle EM bacteria + amino acid fertilizer and supplement beneficial algae. The water change should not exceed one fifth of the total water volume to avoid further stress.
Maintenance facilities: Remove temporary insulation materials, repair damaged greenhouse films and pipelines, clear ice and dead fish around the pool (deeply bury for disinfection).
2. Gradually resume feeding
After the water temperature stabilizes above 8℃, first feed one-third of the usual amount of high-protein feed and observe the feeding situation. Increase the feeding amount by 10% every two days and gradually return to normal.
Continue to add vitamin C and immune polysaccharides to the feed to enhance the physical condition of fish and shrimp and reduce the risk of disease recurrence.
3. Secondary disinfection to prevent diseases
On sunny and warm days, apply chlorine dioxide (100g per mu) throughout the pond. Repeat the application every three days to prevent small melon worm disease and red skin disease.
For ponds with a dirty bottom: Reapply potassium peroxymonosulfate complex salt (800g/mu) to oxidize leftover feed and feces.
According to the latest forecast from the meteorological department, a strong cold front is about to hit. Within the next 72 hours, the temperature in many places will drop sharply by 8 to 12 degrees Celsius, with some areas experiencing strong winds, rain and snow. This time, the temperature drop is rapid, significant and lasts for a long time, which will pose a serious threat to aquaculture!