Although in the past, crab breeding techniques have focused on maintaining healthy crabs through pest control and environmental improvement, these methods are now considered conventional. However, today, environmental pollution and serious diseases and pests have become major obstacles to the sustainable development of the crab industry. The issue of healthy crab cultivation has thus become more prominent, marking an inevitable trend in the current stage of the industry. Healthy crab farming is not just about medication; it involves maintaining a balanced ecological environment, scientific feeding, and proper management throughout the entire process. This ensures that crabs grow strong, healthy, and free from disease. This article explores the severity of crab diseases, their causes, and the urgent measures needed to promote healthy crab farming. **I. Severity of Current Crab Diseases** As crab farming areas and scales expand, the problem of diseases and pests has worsened. In the early 1990s, there were over 10 types of crab diseases, but now there are more than 30. These diseases have spread from localized outbreaks to widespread issues. This year was particularly severe, with over 100 people contacting the author in July, August, and September regarding disease outbreaks. These problems have caused massive economic losses—over one-third of the country’s crabs have been affected, leading to billions in losses. For example, in Jiangsu Province alone, shivering disease caused over a billion yuan in losses. In 1997 and 1998, some farmers in southern Jiangsu suffered total crop failures due to damage from turtles, insects, and leeches. These issues also threaten food safety and the value of basic food products. Without effective prevention and control, the booming crab industry could face significant setbacks. **II. Why Crab Diseases Are Getting Worse** There are multiple complex reasons for the increasing severity of crab diseases. Here are ten key factors: 1. **Water Pollution**: Industrial waste, pesticides, and other contaminants have severely polluted water sources. High concentrations of ammonia, mercury, cadmium, cyanide, and oil can be toxic to crabs. In 1997, an oil spill in the Yangtze River led to over 80% crab mortality in some farms, causing millions in losses. 2. **Poor Site Selection**: Many crab farms lack proper water flow, drainage, and clean environments. Some use muddy fish ponds or poorly designed systems, which make it difficult to raise healthy crabs. 3. **Introduction of Pathogens**: Diseased or latent seedlings can lead to disease outbreaks. For instance, crabs introduced from offshore areas often carry shivering disease, which spreads quickly in crowded conditions. 4. **Degradation of Genetic Quality**: Poor breeding practices, such as inbreeding and using underdeveloped crabs, have led to weaker, less disease-resistant crabs. 5. **Low Dissolved Oxygen**: Insufficient oxygen levels cause crabs to suffocate and increase susceptibility to disease. This is especially common in hot seasons when oxygen levels drop below 4 mg/L. 6. **Improper Use of Medicines**: Many farmers use excessive or inappropriate drugs, leading to resistance and negative side effects. For example, quinolones in nurseries caused developmental issues in crabs. 7. **"Enclosure" Cultivation System**: This system leads to long-term disease buildup because it’s hard to clean the pond thoroughly after each harvest, allowing pathogens to persist. 8. **Unbalanced Density and Management**: Overstocking without proper management increases disease risk. Some high-density farms suffer from higher morbidity, while lower densities with good management see fewer problems. 9. **Nutritional Deficiencies**: Poor feeding practices result in weak crabs. Lack of protein, calcium, and phosphorus affects growth and shell formation, making crabs more vulnerable to disease. 10. **Temperature Fluctuations**: Sudden temperature changes stress crabs, leading to disease outbreaks. Proper water depth and temperature control are essential to prevent this. To address these issues, the government must strengthen regulation, and farmers should focus on science-based practices. **III. Comprehensive Measures for Healthy Crab Farming** 1. **Site Selection and Planning**: Choose clean, well-structured water bodies that meet quality standards. Plan roads, irrigation, and drainage systems to support efficient management. 2. **Pond Construction and Transformation**: New ponds should be large (over 10 acres), with a 3:1 deep-to-shallow water ratio. Old ponds need dredging, disinfection, and planting of aquatic plants to improve the environment. 3. **Rice Field Integration**: Combining crabs and rice can reduce pests and increase profits. Careful planning of ditches and water levels is essential for success. 4. **Preventive Measures**: Install anti-escape barriers and regularly disinfect ponds with safe chemicals like quicklime. Avoid toxic substances like Malachite Green. 5. **Aquatic Plant Management**: Maintain a mix of submerged, emergent, and floating plants covering at least one-third of the water surface. This improves water quality and provides natural food and shelter. 6. **Reform Farming Practices**: Shift from high-density, clustered systems to more sustainable methods. Reduce overcrowding, avoid inbreeding, and manage water and feed more effectively. 7. **Disease-Free Seedlings**: Ensure that seedlings come from healthy, disease-free sources. Use natural disinfectants and avoid overuse of antibiotics. 8. **Water Quality Management**: Monitor and adjust pH, oxygen, and nutrient levels regularly. Change water when necessary, and use microorganisms like photosynthetic bacteria to maintain balance. 9. **Nutrition and Disease Resistance**: Provide balanced diets with sufficient protein, minerals, and vitamins. Adjust feeding based on the crab's life stage and health condition. By implementing these comprehensive strategies, the crab farming industry can move toward more sustainable, healthy, and profitable practices.

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1. Considering the limitation of storage space and storage cost, as well as the fact that video recording in public places such as residential areas is a prerequisite for multi slot and a certain degree of clarity, video recording is generally deleted once a week or so. 15 days for general entertainment venues, 26 days for financial industry, and 3 months to half a year for banks, depending on the current venue regulations
2. The length of the storage time of the monitoring video is generally related to the following points: the capacity of the host's hard disk. Generally, a camera needs about 0.3G-0.5G of hard disk capacity for 24 hours of continuous video recording. Different systems have different parameters, the minimum is 0.15G/24 hours;
3. The number of cameras. The more cameras, the more capacity required. Also, the selection of the resolution and picture quality of the recorded picture will also affect the capacity required for video storage;
4. The video recording mode will also affect the space required for storage. The video recording mode is generally divided into [Mobile Video Recording] and [Continuous Video Recording]. The former means that the host starts to record when a moving object passes through the monitoring range, and does not record at other times. This can reduce the storage space required for video recording; On the contrary, continuous video recording is 24-hour continuous video recording.

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