Introduction of river crab: River crab is also called "crab" and "hairy crab". The head breastplate formed by the combination of head and chest is square and hard. There are a pair of eyes at the front of the body and two pairs of very sharp crab teeth on the side. A pair of appendages at the front end of the crab are called claw feet, and the surface is covered with fluff; There are 4 pairs of walking feet behind the claw feet, which are flat and long; Abdominal limbs have degenerated. The sex of a river crab can be distinguished by its abdomen: the abdomen of a female crab is round, and that of a male crab is triangular.
Eriocheir sinensis is a large crustacean with a body divided into 2 1 segment. Because the head and chest segments are mutually healed, the whole body is divided into two parts: head, chest and abdomen. The back of adult crabs is dark, and the head breastplate is 7cm long and 7.5cm wide on average.
Eriocheir sinensis often burrows in mudflats of rivers, lakes and swamps, moves at night, feeds on fish, shrimp, animal carcasses and grains, often migrates to estuaries every autumn to lay eggs, hatches in March-May of the following year, develops into young crabs, and then returns to the river with fresh meat. It is a popular food.
Eriocheir sinensis, the scientific name of Eriocheir sinensis, is a precious freshwater product with delicious taste, rich nutrition and high economic value.
Medicinal value of Eriocheir sinensis: Eriocheir sinensis belongs to Eriocheir sinensis family, also known as Eriocheir sinensis, or Eriocheir sinensis. There are many kinds of crabs, including river crabs, lake crab, sea crabs and stone crabs. Most of them are medicines. Eriocheir sinensis is salty and cold, with little toxicity, and has the effects of promoting blood circulation, strengthening tendons and bones, and removing lacquer poison. Crab forceps can induce labor and delivery. [3]?
1, less milk after delivery: 1 Crab mashed and boiled in yellow wine. Every day 1 dose.
2, postpartum son's contractions are weak: crabs are scalded and ground, and warm rice wine is served. 65438+ 0.5-3g each time, 2-3 times a day.
3. Leucorrhea: the crab is baked and ground into fine powder, and the yellow wine is delivered, each serving is 15g.
4, postpartum labia, intestinal swelling and pain unbearable: 10 Fresh crabs, mashed and applied to the affected area, fixed with tape, dried and replaced immediately.
5, induced labor, stillbirth: 30-60 grams of crab claws, 9 grams of licorice, add Ejiao after decocting in water; Or decoct with yellow wine or rice vinegar.
6, low back pain, numbness of limbs, paralysis: 9 grams of crab, 3 grams of hippocampus, * * * ground into fine powder. Use it twice and take it with yellow wine.
7, lacquer sores: crabs, leeks. Stir-fry the medicine in a pot and apply the juice to the affected area for about 3 days.
8, frostbite suppuration: live crab burns, fine research, honey applied to the affected area; Or rub it with sesame oil. When applying, you should first smoke and wash the affected area with radish and orange peel. Change it twice a day.
9, paint poisoning: take a proper amount of river crab, mash, rub the affected area.
10, traumatic injury: 1 live crabs (2 small crabs), mashed after birth and washed with hot wine.
1 1, traumatic injury, tendon and bone continuity, blood stasis and swelling: ① If there is no tendon, take crab roe and mash it, stir-fry it slightly, and recover the injury; ② For those with broken bones, mix the crab with hot wine, apply the residue for external use and tie it up. After half a day, you can see the sound of a valley in your bones, and you can recover. Generally, it is changed 1 time a day, and it is changed 2-3 times a day in summer.
12, chronic suppurative dermatosis, negative abscess, lower limb ulcer, tuberculous fistula, etc. Non-stop for a long time: 500g river crab, 500g mosquito and 50g antlers, all burnt, * * * ground into very fine powder (or honey is as big as red beans), and served with yellow wine or warm water. Each dose 1.5-3g, twice a day.
Biometrics 1. biography
River crabs grow in fresh water and breed in river water. Before reproductive migration, they were all young crabs, commonly known as "yellow crabs" because of their yellowish shells. Their gonads are very small and basically undeveloped, and the weight of the liver is far greater than that of the gonads. When it's done the most.
After molting for the second time, it developed into a "blue crab" with a dark green shell and fully developed gonads. Male crabs have thick hairy feet and thick and long bristles. The abdomen of the female crab completely covers the abdomen of the head and breastplate, and the bristles on the edge of the abdomen are long and dense.
The life span of Eriocheir sinensis is very short. In its life history, it has to go through several stages, such as flea larva, megalopa larva, young crab and adult crab. In its lifetime, it needs the larva to molt five times to become a big-eyed larva, and then molt 13- 15 times to become an adult crab. It has only one reproductive cycle in its life, and when reproduction ends, its life ends. Generally speaking, the life span of Eriocheir sinensis is 65438.
2. Living habits
(1) caves
Eriocheir sinensis likes to live in mud flats or caves on the beach in rivers and lakes, or hide in gravel and aquatic plants. The instinct of the river crab is to dig holes, which is also an adaptive way for the river crab to defend against the enemy. Crabs usually burrow on steep slopes with hard soil, with bank slopes of 1:0.2 or 1:0.3, and rarely burrow on gentle slopes below 1: 1.5-2.5, let alone on flat land. This provides a basis for the construction of aquaculture ponds in China.
(2) Eating habits
Eriocheir sinensis has a variety of feeding habits. Under natural conditions, it mainly eats aquatic plants and humus, likes to eat animal carcasses, and also likes to eat snails, mussels, worms and insects. Occasionally they prey on small fish and shrimp. When food is scarce, it will even devour the eggs it holds, and sometimes it will cause similar food competition because of a dead fish. Under normal circumstances, Eriocheir sinensis can easily get plant food, which often constitutes the main component of crab stomach food.
River crabs usually hide in caves during the day and go out for food at night. On land, river crabs don't eat much, and often drag the food on the shore to the underwater or the edge of the cave before eating. In addition to temporarily staying at low temperature, river crabs eat as usual even when they migrate in winter. When the water quality is good, the water temperature is suitable and the bait is rich, the river crab can eat a lot. It can prey on several snails, newly molted soft-shelled crabs and disabled individuals, but river crabs have strong hunger tolerance. If it doesn't eat for 10 days or even half a month, the river crab won't starve to death. Under the condition of artificial culture, it is beneficial to master the "fine-coarse-fine" structure of feeding bait according to the needs of the growth and development of river crabs.
(3) molting and growth of Eriocheir sinensis
The growth process of Eriocheir sinensis is accompanied by the molting of larvae, young crabs or adult crabs, and the larvae metamorphose once every molting, which is divided into one stage. From the molting of megalopa to the first stage of juvenile crab, the body length and weight of each megalopa will advance by leaps and bounds every time it molts. The weight of each big-eyed crab will gradually increase to 250g, and it needs to molt for at least dozens of times, and each molt will pass the survival barrier.
Eriocheir sinensis needs to absorb a lot of water during molting, so its weight is obviously increased. In the later stage of growth, water loss is slow and gradually replaced by tissue growth. The growth rate of Eriocheir sinensis is restricted by environmental conditions, especially water temperature and bait. Usually, early young crabs often shed their skins. The megalopa just entering the lake will shed its skin every 5-7 days and 7- 10 days, forming the second and third stage larvae. With continuous growth, the molting interval will be extended one after another. If the environmental conditions are not good, the molting growth will stop, which is also the reason why individuals of the same age have great differences in body shape under different conditions. After the first, second and third shellings, the crabs should be slaughtered and disinfected at intervals of about once a month. Such as fiber disease, gill disease, rotten limbs, rotten shells and other diseases, the pond should be killed once. According to the previous shelling, the third shelling is usually in late May and early June.
The growth of Eriocheir sinensis is closely related to calcium and phosphorus in water and food. Related experiments show that the weight of newly molted soft-shelled crabs is increased by 30%-40% compared with that before molting, and this period is as long as 1 hour, and it takes at least a few minutes, relying on gills to absorb a lot of water and inorganic salts in water. In natural ponds or lakes, the shells of soft-shelled crabs become hard after 1-2 days. If soft-shelled crabs are raised in distilled water, their ability to absorb calcium ions in water is stronger than that of calcium and phosphorus in compound feed. Before molting, the total amount of calcium in the shell is required to be equal to that in the body, and the total amount of phosphorus in the body is 52.2 times that in the shell.
In order to cooperate with the growth and molting of Eriocheir sinensis, 5 kg of calcium chloride and 2.5 kg of disodium hydrogen phosphate (or quicklime or calcium superphosphate) were applied per mu (average water depth 1 m) in intensive crab ponds every week. The ratio of calcium to phosphorus must be considered in the compound feed of Eriocheir sinensis, and the ratio of calcium chloride to disodium hydrogen phosphate is 2: 1, so as to ensure the material needs of Eriocheir sinensis for growth and molting.
The method of steaming river crabs is 1. The crab is bought and soaked in clear water for ten minutes, and then cleaned with a small brush.
2. Turn the crab upside down and steam it in a steamer for ten minutes.
3. Cut ginger into pieces, add vinegar and juice for later use.
4. Take crabs and dip them in the adjusted juice.
Crab diet taboo 1, crab is a cold food, you must eat a little ginger, because ginger is warm and can drive away the cold.
2. When steaming crabs, the belly should be up, so that the crab oil will not flow out and keep the flavor.
Crabs can't be eaten with persimmons.