Impact and Harm of Toxic Gases NH3-NO2 in Shrimp Ponds
1. Sources
The primary sources of toxic gases NH3 and NO2 in shrimp ponds are nitrogen compounds derived from:
- Shrimp Waste: During feeding, shrimp absorb only 25% of the protein in their food. The remaining 75% is excreted as waste.
- Feed: Some protein in the feed dissolves into the water. Excess feed that is not consumed falls to the pond bottom, leading to pollution.
- Decomposing Shrimp and Algae: Dead shrimp and fallen algae decompose, releasing nitrogen compounds.
- Contaminated Water Sources: Water from rivers that enter the pond may carry decomposing plant and animal matter, as well as excess fertilizers like urea and NPK.
2. Mechanism
- When pH is between 7.5 and 8.5, ammonia (NH4+) predominates. Although the environment is suboptimal, it does not severely affect shrimp.
- When pH exceeds 9, ammonia (NH3) becomes dominant, which has a significant negative impact on shrimp.
- Specifically, the bacteria Nitrobacter sp. and Nitrosomonas sp. are aerobic microorganisms that thrive and function effectively in high dissolved oxygen environments.
- Dissolved Oxygen's Role: High levels of dissolved oxygen are critical for detoxifying NH3. Adequate oxygen accelerates the nitrification process. This process occurs naturally but relies on low bacterial populations and low dissolved oxygen in natural settings, leading to slow nitrate formation. This slow process causes NH3 and NO2 levels to rise quickly, resulting in high concentrations in the pond. Consequently, shrimp growth is slowed, and mortality risk increases.
3. Symptoms of Toxic Gas Impact on Shrimp
- Slow growth.
- Shrimp gathering near the surface or gasping for air.
- Disease outbreaks and mass mortality.
4. Management Strategies
- Use Beneficial Bacteria: Apply beneficial bacteria at the start and regularly to increase beneficial microorganism levels in the pond.
- Increase Dissolved Oxygen: Ensure high levels of dissolved oxygen.
- Maintain pH Balance: Keep pH levels within the acceptable range, avoiding extremes.
- Prevent Overfeeding: Adjust feeding amounts, especially in cooler temperatures, to avoid excess feed.
- Regular Water Changes: Perform water changes periodically to manage toxin levels.
Ngày đăng : 14/08/2024
1741 View
Other Articles
AQUA MINA | CELEBRATING THE 67TH ANNIVERSARY OF VIETNAM’S TRADITIONAL FISHERIES DAY
Restructuring seed production to enhance the competitiveness of the aquaculture industry
AQUA MINA COMMITS TO NO PRICE INCREASE – 15% OFF PVC Knife Gate Valves, Double Flanges, and Elbow Flanges TO SUPPORT SHRIMP AND FISH FARMERS
Global shrimp prices – Week 12: Ecuador shrimp prices recover, while India and Indonesia remain stable
The global surimi market is projected to grow strongly.
Cà Mau: Expanding the RAS-IMTA model toward sustainable, zero-discharge shrimp farming.
From seed stock to farming equipment, high-tech aquaculture attracts strong interest in Ho Chi Minh City
Shrimp industry enterprises proactively adapt to global fluctuations
DAY 3 – AQUA MINA | STRONG CONNECTIONS – A MEMORABLE CLOSING AT VIETSHRIMP AISA 2026
DAY 2 – AQUA MINA | DEEP INSIGHTS & SMART SOLUTIONS FOR MODERN AQUACULTURE
DAY 1 – AQUA MINA | A POWERFUL OPENING AT VIETSHRIMP ASIA 2026
OFFICIAL OPENING of the International-Scale Aquaculture Exhibition Series | See You Again with AQUA MINA at VietShrimp Asia 2026
.jpg)