Hairy crabs, also known as Eriocheir sinensis, are economic crabs, also known as river crabs, hairy crabs, clean water crabs and hairy crabs. It is a famous food in China. Its claws are used for foraging and resisting enemies, and the inside and outside edges of the palm are densely covered with fluff, hence the name Eriocheir sinensis. Omnivorous animals, such as fish, shrimp, snails, mussels, worms, earthworms, insects and their larvae, can all be used as animal feed for hairy crabs.

Crabs contain more vitamin A, which is helpful for skin keratinization. It can also supplement calcium for rickets in children and osteoporosis in the elderly. Lakes are widely distributed in the north and south coastal areas of China, among which the Yangtze River system has the largest output and extremely delicious taste. Among them, Gucheng Lake Hairy Crab is the most famous, which has always been called the crown of crabs, and has been recognized as a well-known trademark in China by the State Administration for Industry and Commerce. Other famous hairy crabs are Taihu Hairy Crab, Yangcheng Hairy Crab and Changdang Hairy Crab.

1 species information?

Also known as river crab, hairy crab, clear water crab, hairy crab or crab. It is an economic crab.

Chongming people call it "old hairy crab" because it has hair on its two big claws. Its birthplace is in the waters of the Yangtze River estuary of Chongming Island. There are more than 300 species of crabs in all rivers and lakes in the world, of which about 20 species are edible. The most famous one is Eriocheir sinensis in China.

Eriocheir sinensis

Every winter, Eriocheir sinensis will swim to the nearby waters, where salt and fresh water meet to breed, and then the crab seedlings will be caught by fishermen on the island. Crab farmers raise crabs to the size of buttons, which is called buckle crabs. Farmers all over the country come to buy them and take them back to raise them.

In the subsequent growth process, Eriocheir sinensis will choose an aquatic environment suitable for its own growth and development, among which the cultured hairy crabs are called "the best among crabs" because of their unique water characteristics. With years of experience in aquaculture, tell consumers a unique identification method:

1. fullness (kneading method): The difference between hairy crabs and other crabs lies in the fullness of meat. You can pinch the calf of the hairy crab and feel whether the meat is full. If it is not full, it feels hollow when pinched.

2. Green back (burning method): The back of hairy crabs is crab shell green, bright and refreshing, and turns red after cooking. The crab soil in other lake areas is heavy in color and grayish red after cooking.

3. White belly (brush method): The belly of hairy crabs is white, shiny white, but not pure white. Because there are water stains in the lake, it should be yellowish with water stains, which is different from the gray belly of crabs in other lake areas. If the shell is lightly brushed with a brush, the dirt with a little water stain attached to the shell can be brushed off.

4. Golden claws (can be tested on smooth glass or floor tiles): The claws of hairy crabs are as golden as tobacco, with two claws and eight claws, which are strong and powerful; It can stand up and crawl freely on smooth glass plates or floor tiles. The crab claws in other lake areas are thin and weak, and there is no obvious golden color on the claw tips.

5. Yellow hair (the method of squeezing claw hair can be used): the fluff on crab claws is thick and soft, and the hair color is refreshing and yellow. The crab hair in other lake areas is very earthy and unclean. This method requires special attention to safety and is easy to be caught by fingers.

2 morphological characteristics?

Body structure

The breastplate is round and square, and the back half is wider than the front half. The back is convex, the forehead and liver area are concave, and there are 6 symmetrical protrusions in front of the stomach area, each of which has particles. The stomach area is distinguished from the heart, and there are pits around the former. The forehead is wide and divided into four teeth. The upper edge of the eye socket protrudes near the middle and is triangular. There are four sharp teeth in the front edge, the last one is the smallest, and a long line is introduced to run obliquely outside the gill area; There is also a ridge along the inside of the back edge. Claw foot, male is bigger than female, the inner and outer surfaces of metacarpal joints and knuckle bases are densely covered with fluff, the inner corner of wrist joints has spikes, the rear edge of long joints has spikes and the long joints of walking feet. The last three pairs are relatively flat, and the trailing edges of the wrist joint and the anterior joint have bristles. Step 4, the dorsal and ventral edges of the forefoot joints and knuckles are densely covered with bristles. Abdomen, female round and male pointed. The head breastplate is 54.6 mm long and 6 1.0 mm wide. ?

body type

The body is nearly round, the back of the head breastplate is grass green or dark green, and the ventral surface is gray. There are four pointed odontoid processes on the forehead edge of the head breastplate, and there are also four odontoid processes on the front edge. The fourth tooth is small and obvious. The abdomen is flat, the female is oval to round, and the male is slender and bell-shaped, but the abdomen of male and female is triangular in the juvenile crab stage, which is difficult to distinguish. Claw feet are used to feed and resist enemies, and the inner and outer edges of the palm are densely covered with fluff, hence the name Eriocheir sinensis. Four pairs of walking feet are the main crawling organs, and there are 1 sharp teeth at the end and front corner of the long segment. There are 4 pairs of female abdominal limbs, located in the 2nd to 5th abdominal segments, bipedal with dense bristles. The inner limb is mainly used for attaching eggs. The male crab only has 1 and a second abdominal limb, which is specially used as an adapter.

3 living habits?

He often lives in caves in rivers and lakes, swings on mud dikes, hides during the day and comes out at night, and feeds on animal carcasses or grains. Every autumn, it grows plump and often swims back to the offshore to breed. The eggs carried by the mother hatch from March to May of the following year. After many metamorphosis, the larvae develop into young crabs, then return to the river and continue to grow in fresh water. Every autumn, when crabs breed and return, fishermen often set up a hairpin in rivers and lakes and trap them with lights at night. ?

Eriocheir sinensis lives in freshwater lakes and rivers, but breeds in brackish water at the estuary (salinity 18-26/ 1000, specific gravity1.016-1.020). From June to July every year, newborn crabs swim back to fresh water and live on the banks of rivers and lakes. I like living in caves, or hiding in gravel and water plants. When digging a hole, 1 is mainly used to clamp the feet, and the feet only play an auxiliary role. Feeding on aquatic plants, benthos, organic debris and animal carcasses. Grab it with your paws when feeding, and then send the food to your mouth. When the nutritional conditions are good, the weight of young crabs can reach 50 to 70 grams, and the maximum weight can reach 150 grams. The gonads are mature and can participate in reproductive migration with the second-year-old crabs. If the stocking density is high or the growth is slow, the gonads of the second age are difficult to mature and cannot participate in reproductive migration.