Fresh aquatic products are an important non-staple food on the market. They are an important source of nutrients such as protein intake by human beings. At present, seafood aquatic products for human consumption have processed products and fresh products. In recent years, with the continuous improvement of living standards, people have higher and higher requirements for the quality of seafood and aquatic products, especially the demand for fresh seafood seawater products. At the same time, with the development of aquaculture industry, sea freshwater aquaculture production is developing towards industrialization, intensification and specialization. Marine fishing is also becoming mechanized. The variety and quantity of seafood are increasing, and the grades are gradually increasing. However, it is necessary to transport fresh seafood to the mainland and supply seafood restaurants in various cities. Therefore, it is a requirement of the times to do a good job of living transport so that people can eat fresh seafood and aquatic products. For many years, aquatic products have been stored and sold in a cold storage and freezing manner, and the processing and processing are not proper, and the loss and waste are great. In recent years, after promoting the sale and marketing of seafood in fresh form, the economic benefits have been greatly improved. This is because the fresh seafood and aquatic products taste good and the market is good. The price is much higher than that of cold storage and frozen products. Although the cost of living transportation is relatively high, it can save the cost of cold storage and freezing, and it can be of high quality and high price. Therefore, it is more profitable to operate fresh seafood and aquatic products. With the development of social economy, the demand for live fish live shrimp is increasing rapidly. They prefer to pay more for live fish and shrimp than to eat frozen seafood. More and more hotels and restaurants provide customers with Live seafood and aquatic products, especially high-end lobster, abalone, grouper and so on. It can be seen that living transportation is one of the important links in the sales of aquatic products. Its most important job is to avoid the loss of seafood aquatic products and the loss of fish due to adverse environment during transportation.

　　The main factor affecting the development of the live seafood market is that many operators lack scientific knowledge about the preservation of seafood before harvesting and transport to hotels. The key factors in live transport Before carrying out live transport, it is first necessary to recognize that the transported object is in a different environment than the original living environment. Due to the significant difference in the environment, the physiological condition of the living body will change. In severe cases, it will threaten the survival of the living body and directly affect the survival rate of transportation. Let us analyze the main factors affecting the physiological changes of living organisms during the transportation of aquatic products: oxygen, temperature, carbon dioxide, ammonia nitrogen and so on. 1. Oxygen and oxygen deficiency will make seafood aquatic products unable to breathe normally during transportation. If there is severe hypoxia, it will cause suffocation and death, thus affecting the survival rate. In general transportation, the dissolved oxygen in water should be kept above 5mg/L. To this end, supply oxygen during transportation. There are several methods for supplying oxygen: A often injects new water in the course of transportation to increase the oxygen content in the water. The temperature and salinity of new water are generally similar to those of old water. B moderately oscillates the conveyor to cause fluctuations in water to increase the contact surface of water and air and increase dissolved oxygen. Be careful that the transporter cannot be shaken too much to avoid harming the fish. C. Set some mesh plates on the water surface of the transporter to make it rotate slowly and slowly to increase the water oscillation. D Install an aerator or an inflator during transportation to increase oxygen at any time.

　　2. Temperature Fish, etc. are temperature-changing animals, and the body temperature changes with the temperature of the water. All kinds of aquatic products have their own temperature range, which is easy to die beyond the appropriate temperature range. The water temperature must be controlled during transportation. The temperature is high, the metabolic rate and oxygen consumption of the organism and the resulting carbon dioxide and ammonia content are also high; at the same time, the dissolved oxygen is lowered, and the affinity of blood and oxygen in the living body is also weakened. Therefore, when changing water, adding new water or adding ice, it is necessary to prevent sudden temperature changes. The water temperature is abrupt, and the internal function of the fish cannot be adjusted immediately to adapt to this change, and the fish is susceptible to disease. In summer, the temperature is too high, and some crushed ice can be placed on the surface of the water to gradually melt it, which can lower the water temperature. In winter, the water temperature is too low and anti-freezing measures should be taken. The change of water temperature is generally not more than 5 °C. 3. Carbon dioxide fish in the water will emit carbon dioxide, which will increase the concentration of carbon monoxide in the water. It has been confirmed that the concentration of carbon dioxide on fish is 60-100mg/L. Even if the dissolved oxygen in the water is saturated, the fish can't Normal breathing will suffocate and die. During normal transportation, the concentration of carbon dioxide contained in the water tank is 20×10-6-30×10-6. If the concentration of carbon dioxide exceeds this range, it should be inflated in water to remove carbon dioxide and increase dissolved oxygen in the water to maintain the normal living environment of the fish.

　　4. Ammonia nitrogen The content of ammonia nitrogen in water is increased due to the action of feces, residual baits, dirt and bacteria discharged from fish and shrimp. When ammonia nitrogen in water accumulates to a certain concentration, it will weaken the oxygen absorption capacity of fish and shrimp, and hinder the living body. Normal breathing. Ammonia is very harmful to fish. When the concentration exceeds 0.012×10-6, the fish is fatal. Usually, when the water temperature rises, the ammonia excretion of the fish increases, and the ammonia discharge of the small fish is larger. Therefore, a large amount of oxygen should be added during transportation to prevent the fish from being poisoned and causing damage. 5. The osmotic pressure of the organism The surface of the fish, shrimp, etc. has secreted mucus or scales, which can maintain the osmotic pressure balance in the body. During the transportation process, due to the vibration of the transportation equipment, the surface of fish, shrimp, etc. is often mechanically injured by the water tank or cage, causing the scales and mucus to fall off, the skin is rubbed, and the osmotic pressure in the body is out of balance, reducing The fish's resistance to disease. Therefore, damage to the surface of the fish should be minimized or avoided to maintain normal osmotic pressure.

　　6. Before the body of the organism is transported, if the organism such as fish and shrimp is strong, the ability to adapt to the bad environment is strong, and the survival rate of transportation is high. When seafood and aquatic products are caught in transport equipment, because they are not adapted or frightened by the new environment, they will swim and struggle fiercely, so that the muscles will contract. At this time, if there is not enough oxygenated blood to replenish, a large amount of lactic acid will be accumulated in the muscle blood vessels, the pH value of the blood will decrease, and the utilization rate of oxygen by the acidic blood is low, and the fish and shrimp are within 24 hours. It is not easy to return to normal. The speed of recovery depends mainly on the type and constitution of the organism. Therefore, it is necessary to select robust individuals before transportation to ensure the survival rate.

　　7. Prevent the breeding of bacteria If the aquatic products in the transportation process are in an uncomfortable environment, they will secrete a lot of mucus and excretion. These secretions will become the culture agent of the bacteria, and the bacteria will multiply rapidly. On the one hand, the bacteria can cause the fish to be infected; on the other hand, the growth of the bacteria requires oxygen consumption, which reduces the dissolved oxygen content in the water, and easily causes the seafood to die due to lack of oxygen. In addition, during the transportation process, if the fish's digestive tract leaves residual food, the bacteria will multiply with the intestines and stomach, and the fish body is weaker when transporting, which is more susceptible to diseases, in order to improve transportation. Survival rate, seafood in the temporary maintenance before transportation, we must first "eliminate the belly", discharge the feces, thereby avoiding or reducing the pollution and deterioration of water during transportation, and improve the survival rate of seafood.