Basic introduction Chinese name: Corbicula fluminea, alias: Corbicula fluminea, Bombyx Batryticatus, Oncomelania hupensis, Salad, Bombyx Batryticatus, Animal kingdom: mollusk, English name: Asian Clam, basic introduction, basic information, origin distribution, environmental adaptation, medicinal value, ornamental, breeding technology, basic overview, breeding introduction, basic information. Rivers and lakes in China are all produced. Widely distributed in China's inland waters, rich in natural resources. They dig holes in the surface layer of underwater soil and feed on plankton, with fast growth and strong reproductive ability. Besides natural resources, it is also suitable for artificial breeding. Russia, Japan, North Korea and Southeast Asian countries are all distributed. Environmental adaptation Corbicula fluminea is a bivalve aquatic organism with strong environmental adaptability. It absorbs elements from the surrounding environmental medium and forms its carbonate shell through the secretion of its software. Therefore, the chemical composition of Corbicula fluminea shell should reflect the geochemical characteristics of environmental media. A comparative study on the composition of trace elements in the shell of Corbicula fluminea in Nanming River, Guiyang, and the river water pollution showed that with the deterioration of the river water quality, the contents of Pb, Cd, Cu, Co, Fe and Mn in the shell of Corbicula fluminea increased, with the largest increase proportion of Pb reaching 285%, followed by Cd, Cu, Co, Fe and Mn, which were1respectively. On the contrary, the contents of Ni, Na and Zn in the shell of Corbicula fluminea in the heavily polluted reach are relatively low, among which the reduction rate of Ni is the largest, accounting for 63%, followed by Na and Zn, accounting for 18% and 14% respectively. This preliminary study proves that Corbicula fluminea is indeed adjusting its shell with the change of geochemical conditions of water quality. The contents of trace elements such as lead, cadmium, copper, cobalt, iron and manganese are consistent with the changes of water pollution, which can be used to reflect the pollution characteristics of environmental media. Clam shell is rich in nutrition, which can be eaten fresh, dried, canned and used as medicine. It has the effects of stimulating appetite, promoting lactation, improving eyesight, inducing diuresis, treating beriberi, eliminating dampness and removing toxic substances, and sobering up, and can also be used for treating liver disease, measles and fever. Corbicula fluminea is a natural bait for benthic fish and poultry. Shell powder can be used as raw material of lime. Meretrix meretrix is also the second intermediate host of echinococcosis, and it is easy to suffer from echinococcosis if eaten raw or undercooked. Living habits Corbicula fluminea can reach maturity in three months and can breed all year round. The most full gonad period is May-August, and the peak reproductive period is May-June. The life span of Corbicula fluminea is about 5 years, and the best harvesting and utilization period is l ~ 2 years old. It takes more than 3 years to make the shell of handicrafts. Corbicula fluminea inhabits rivers, lakes, ditches, ponds and estuaries, and mainly takes sand, sand mud or silt as the substrate. Living in caves in underwater camps, larvae inhabit the depth of 10-20mm, and the largest can live in seclusion for 20-200mm, with a maximum distribution of 20-50 mm. Feeding on plankton (such as diatoms, green algae, euglena, rotifers, etc.) filtered by gills. ) is a passive feeding method. Corbicula fluminea is hermaphroditic, but some hermaphroditic individuals are also found. The breeding season of Corbicula fluminea in Fujian is from May to August every year, when a large amount of white mucus appears at the bottom of the river bed. After the floating life of Corbicula fluminea larvae ends, they sink to the bottom of the water for 15-30 days, and then grow into a 2 mm Corbicula fluminea in about 1 month, which can grow to 10 mm in 3 months, and the life span of Corbicula fluminea is about 5 years. Biological introduction shells are of medium size and have a triangular round bottom. Generally, the shell length is about 3 cm, and the shell height is similar to the shell length. The two shells expand. The top of the shell is high and slightly forward. The surface of the shell is shiny, and the color changes with the environment, often brown, yellow-green or dark brown. The surface of the shell has rough ring ribs. Ligaments are short and protrude outside the shell. Hinges are developed. The left shell has three main teeth, and the front and rear teeth are 1 respectively. The right shell has three main teeth, two front teeth and two front teeth with small teeth on it. The scar of adductor muscle is obvious, and the scar of coat is deep and obvious. Bivalves 1 family. Global distribution. Represents a small to medium-sized shell of an animal belonging to the genus Corbicula. The shell is thick and firm, and its shape is round or nearly triangular. The shell surface is glossy with concentric veins, and the inner surface of the shell is white or blue-purple. The hinge part has three main teeth, the left shell has 1 front and rear teeth, the right shell has two front and rear teeth, and the upper end of the side teeth has serrations. The feet are big and tongue-shaped. Androgyny or hermaphroditism. Fertilize in water, develop into larvae, and then sink to the bottom to live in benthic organisms. It can mature in about 3 months. There are also types of viviparous. Habitat in fresh water and Yuxian fresh water. Meat is delicious, with high nutritional value and can be eaten. It is also a natural feed for fish and waterfowl. It is also a traditional Chinese medicine, which has the effects of promoting lactation, improving eyesight, diuresis, dehumidification and detoxification. Shells can be calcined with lime. Clam is the second intermediate host of Echinococcus. The shell of Corbicula fluminea in China is about 40 mm long and 30 mm high. The shell is thick and hard, slightly triangular and slightly symmetrical on both sides. The shell surface is yellow-green, dark brown and black with luster, and the inner surface of the shell is lavender, bright purple and porcelain luster. Habitat in rivers and lakes. Edible, can also be used as bait for fish and poultry, and can also be used as farmland fertilizer. Morphological characteristics The shell is of medium size with a round triangle at the bottom. Generally, the shell is about 3 cm long, and the height and length of the shell are similar. The two shells expand. The top of the shell is very high and slightly forward. The surface of the shell is shiny, and the color changes with the environment, often brown, yellow-green or dark brown. The surface of the shell has rough ring ribs. Ligaments are short and protrude outside the shell. Hinges are developed. The left shell has three main teeth, and the front and rear teeth are 1 respectively. The right shell has three main teeth, two front teeth and two front teeth with small teeth on it. The scar of adductor muscle is obvious, and the scar of coat is deep and obvious. The value and economic value of Corbicula fluminea culture are not only suitable for large and medium-sized lake release and proliferation, but also suitable for small-scale water surface or pond feeding and fertilization culture. Culturing Corbicula fluminea has the advantages of low cost, high yield, easy fishing, stocking and harvesting in the same year, and remarkable economic benefits. Corbicula fluminea meat is delicious and nutritious. Besides fresh food, it can also be processed into dried, canned, frozen or salted Corbicula fluminea meat. This is popular not only in China, but also in Japanese, Korean and some countries in Southeast Asia. Generally, the shell length of export commodity river gauge is 25 ~ 36mm, the shell height is 22 ~ 33mm, and the shell width is16 ~ 28 mm. The individual weighs 4 ~ 7g, and the weight is 0/60 ~ 220 per kg/kloc. Corbicula fluminea can also be used as farmland fertilizer. The application of broken mussel meat and broken inkstone shell can improve acidic soil. Medicinal value In recent years, with the increase of Corbicula fluminea export, the price of Corbicula fluminea has been rising. Japan and South Korea import tens of thousands of tons of fresh Corbicula fluminea to China every year to sober up and protect the liver. Corbicula fluminea not only can be used as traditional Chinese medicine, but also has the effects of appetizing, promoting lactation, improving eyesight, diuresis, eliminating dampness and toxin, treating liver diseases, reducing fever of measles, relieving cough and resolving phlegm, and relieving alcoholism, and is also a natural bait for livestock and fish. Mixing crushed clam meat and clam shell with compound feed can promote the growth and reproduction of livestock and poultry, and improve the egg production rate of poultry and the milk production rate of livestock. Corbicula fluminea can also be used as fresh bait for some special aquatic products. In recent years, with the development of turtle, carp, eel and crab culture, people began to pay attention to Corbicula fluminea culture. Ornamental Corbicula fluminea can be raised as ornamental shellfish, and it can be used as a "filter" in aquarium to purify water and eat unicellular plants and microorganisms in water. To satisfy the appetite of Corbicula fluminea, it is necessary to supplement green algae and spirulina regularly. Basic overview of culture technology Corbicula fluminea meat is rich in nutrition and simple to raise, which can be used as bait for pond culture. Introduction to culture: Corbicula fluminea is fertilized in vitro, and the eggs develop into disc larvae. After completing the floating life stage, the shells begin to grow and sink to the bottom of the pond, and the shells are buried in the mud at the bottom of the pond. Only straws are put into the water to breathe and swallow the bait. The pond where Corbicula fluminea is raised cannot be injected with pesticides and fertilizer water, which is the most likely to cause Corbicula fluminea to die. The water quality should not be too fertile. Sand is suitable as the bottom material of a pond. The water depth is kept at about 1 m. 60~ 130 kg of Corbicula fluminea seedlings can be stocked per mu. Corbicula fluminea can't continue to breed in the pond, and the number of seedlings put in the next year can be reduced appropriately. The specification of Corbicula fluminea seedlings is 800~4000/kg. If you buy clams from other places, you can transport them in sacks or straw bags. In order to reduce the death on the way, keep a certain humidity and don't pile it too thick. Before stocking, drain the pool water, expose it to the sun for 2~3 weeks, and then inject water. In pond culture, bean flour, wheat bran or rice bran should be fed, and chicken manure or other farmyard manure can also be applied. The growth rate of Corbicula fluminea depends on the feeding conditions. The average weight of fry is about 0. 1 1 g, and after feeding 1.5 months, it can gain 4 times, reaching 0.45 g; It can reach 0.91g in 3 months; 4~4.5 months can reach 2.25 grams; It can reach 4 grams in May-June and 5.4 grams in July-July-May, and its weight is 50 times that of the original fry, so it can be harvested at this time. When fishing Corbicula fluminea, you can use an iron rake with a net. After fishing, iron is used to screen out the size, and smaller individuals are still put back into the original pond to continue feeding. Corbicula fluminea can also be mixed with silver carp, bighead carp and grass carp, but not with herring and carp. The crushed Corbicula fluminea is a good bait for Monopterus albus, and Corbicula fluminea can be directly fed.