Second, the growth environment and habits of crabs
1. Hairy crabs like to live in caves in seclusion. Aquatic plants can cover hairy crabs without shelling and are the main food of hairy crabs. Only by raising more than 60% aquatic plants can delicious hairy crabs be produced. Without lush aquatic plants, hairy crabs can only get into the mud and shed their shells. Clear water can make sunlight shine directly on the bottom of the water, which is beneficial to the growth of aquatic plants and provides good growth conditions for hairy crabs. Therefore, the shell of high-quality hairy crabs must be cyan with a hint of aquatic plants green.
Step 2: Find food
Eriocheir sinensis spends most of its time looking for food. They are generally not picky about food. They can eat all the food they can find with their claws. Small fish and shrimp are their favorite, but some crabs eat seaweed, even animal carcasses and plants.
3. Crab Competition
Crabs eat other animals, and other animals may eat crabs. For example, humans regard crabs as delicacies, and waterfowl also eat crabs. Some fish like to eat crab feet just like humans. Young crabs and underage crabs may be preyed by other marine life when floating in the sea in groups, so crabs should lay a lot of eggs when laying eggs to ensure the survival rate of crabs.
4. Crab culture
They rely on the mother crab to give birth to small crabs, and every time the mother crab will lay a large number of eggs, the number can reach more than one million. After these eggs hatch in the abdomen of the mother crab, the larvae can leave the mother and float around with the coastal current. After molting several times, it grows into a big-eyed larva, and after molting several times, it grows into a young crab. The appearance of a young crab is almost the same as that of an adult crab, and it becomes a crab after molting several times. Most sea crabs are directly discharged into the sea without hatching after their eggs mature.
Third, the climate situation in Tianshui, Gansu Province
1, Tianshui belongs to temperate monsoon climate, and it belongs to temperate semi-humid climate near the urban area. The south of Suzhou-Liyuan line belongs to the north subtropical zone, with an annual average temperature of 1 1℃. The hottest month is July with an average temperature of 22.8℃. The maximum temperature in Leng Yue is 65438+ 10 month, and the average temperature is -2.0℃. September to165438+1October is the best tourist season in Tianshui. The annual average precipitation is 49 1.7mm, which gradually decreases from southeast to northwest. The annual rainfall in the south subtropical forest area is 800-900 mm, the rainfall in the central and eastern mountainous areas is more than 600 mm, and the rainfall in the north of Weihe River is less than 500 mm.
2. The annual average sunshine hours is 2 100 hours, which is slightly higher in Weibei than in Guanshan and Weihe River basins, and the sunshine percentage is 46-50%. Spring and summer account for 26.6% and 30.6% of the annual sunshine respectively, and winter accounts for 22.6%. Winter is not cold, summer is not hot, spring heats up quickly, and autumn is rainy. The climate is mild, with four distinct seasons, abundant sunshine and moderate precipitation. The extreme maximum temperature is 38.2℃, and the extreme minimum temperature is-17.4℃.