The environmental indicators affecting the growth of shrimp, mainly temperature, light, dissolved oxygen, pH, transparency and substrate.

(1) temperature

The shrimp is a warm animal, as long as the water temperature is not below 0 ℃, can live normally. Water temperature above 14 ℃ began to feed, 18 ℃ when the intensity of feeding increased. Water temperature at 33 ~ 35 ℃, the shrimp growth is still faster. The minimum water temperature for spawning shrimp 18 ℃, the optimal water temperature for growth of 25 ~ 30 ℃. Penaeus shrimp to the sudden cooling of the adaptability is very strong. Experimental studies have shown that the water temperature from 28.5 ℃ to every 10 minutes to reduce the speed of 1 ℃ gradual cooling, has been reduced to 4 ~ 6 ℃, and then naturally warmed up to continue to feed, and no deaths have occurred, which provides a convenient low-temperature long-distance transportation. Temperature is an important environmental factor to stimulate the molt of green shrimp. In natural waters, December to February of the following year during the overwintering period, generally do not molt; March to April molt relatively fewer times; May to August, the water temperature is higher, the green shrimp molt more often, fast growth. (2) light

Because of the adult shrimp with negative phototropic, sunny daytime generally lurk in the shade, the night under low light to swim around, to shallow water to feed. But in the reproductive season, the shrimp also come out during the day to mate. In the case of artificial culture, during the daytime baiting, will also come out to look for food, but the number is much smaller than at night. Therefore, the baiting of the shrimp should mainly be carried out in the evening, for the shrimp to come out at night to feed. Shrimp molt is usually also hidden at night, the weaker the light the better, and strong light or continuous light to slow down the molt. Therefore, in the process of shrimp culture, usually require the pool water to maintain a relatively fat state, the transparency can not be too large. (3) dissolved oxygen

Green shrimp have high requirements for dissolved oxygen, extremely intolerant of low-oxygen environment, its oxygen consumption rate and suffocation point are higher than the main culture of fish (Table 3). Therefore, the fish pond oxygen deficiency, shrimp is always the first floating head; when the pond fish floating head, shrimp has been hypoxia asphyxiation death. The optimal dissolved oxygen for the growth of shrimp is more than 5 mg / liter, generally not less than 3 mg / liter. The intensity of respiration of green shrimp depends on the oxygen content of the water. Oxygen consumption rate of the shrimp is closely related to the sex of the shrimp, holding eggs or not, day and night and weight and other factors. The male shrimp of the blue shrimp oxygen consumption rate is higher than the female shrimp, the egg-holding shrimp oxygen consumption rate is higher than the non-egg-holding shrimp, higher at night than during the day, the larger the individual, the lower the rate of oxygen consumption.

Table 3 Comparison of oxygen consumption of penaeid shrimp and several species of farmed fish [mg / (g?)] Name First Second hour)] Name First Second Water temperature (℃) Average oxygen consumption rate Water temperature (℃) Average oxygen consumption rate Summer flower Grass carp Silver carp Bighead carp 22.5～23.928.5～29.628.5～29.7 0.3540.6320.41228.6～29.528.9～29.929.2～32.3 0.3250.4830.5962 age Species Cyprinidae Grass carp bighead carp 26.0～26.627.022.3～28.226.3～27.9 0.3760.2380.2100.19126.1～27.026.4～26.928.2～28.728.2～29.0 0.2610.1720.2640.161 Green shrimp Juvenile shrimp egg-holding shrimp male shrimp female shrimp 27.5～ 29.022.5～24.023.5～24.523.5～25.0 1.4290.5390.6340.48526.024.5～27.0 1.7990.708 (4) pH pH has a direct and indirect effect on the shrimp. pH acidic water, the shrimp blood pH can be reduced, weakening its oxygen-carrying capacity, resulting in hypoxia; pH too high water, the corrosion of the water. Too high water, corrosion of gill tissue. Too high or too low pH will affect the molt and growth of shrimp, but also microbial activity in the water is inhibited, organic matter is not easy to decompose, affecting the absorption and utilization of bait organisms, resulting in water quality barren, but also to promote the growth of harmful organisms such as pathogens and shrimp disease. Therefore, shrimp aquaculture water pH, in the nursery stage to 7.2 ~ 8.0 is appropriate, juvenile shrimp and adult stage to 7.5 ~ 8.5 is appropriate. (5) transparency

Transparency of the water body of shrimp aquaculture, in different stages of the requirements are not the same. Seedlings and larvae cultivation period due to cultivate biological bait, water quality requirements of some fat, transparency mastered in 25 ~ 30 cm is appropriate. With the growth of shrimp specifications, shrimp natural bait structure has changed, from feeding on natural biological bait to feed mainly plant and animal artificial bait, the transparency of the water at this stage should be 35 to 45 centimeters for good. (6) substrate

Laden shrimp like to live in shallow water, especially like to live in the water plants, gentle currents, the substrate for the mud bottom of the water body. The different substrate conditions of the shrimp habitat test showed that: in the plastic plate area, the average occurrence of shrimp only 5.8%, 7.5% of the sandy area, the mud bottom area of 25.8%, while the average occurrence of the mud bottom area of 60.9% of the occurrence of water plants. It can be seen that the shrimp especially like in the grassy mud bottom environment habitat. (7) Other

Green shrimp adaptability, can survive in freshwater, low salinity water and high hardness water; but the most suitable in the moderate hardness, neutral or alkaline water quality growth. Green shrimp suitable for growth of water quality requirements of ammonia nitrogen & lt; 0.2 mg / liter, nitrite & lt; 0.05 mg / liter, nitrite content is too high will inhibit the green shrimp respiration. The water used for shrimp aquaculture should meet the fishery water quality standards, the water source is not polluted, the water quality is fresh.