The shell of the river clam is medium-sized, round-bottomed and triangular, with the height of the shell approximating the length of the shell, the two shells swollen, and the top of the shell high and slightly to the front. The shell surface is glossy, and the color varies according to the environment, often brownish-yellow, yellowish-green or blackish-brown. The shell surface has rough ring ribs. The ligaments are short and protrude outside the shell. The gibbous part is well developed, the closed shell muscle scar is obvious, and the coat scar is deep and remarkable. River corbicula inhabits freshwater lakes, ditches, ponds and rivers where salt and fresh water meet, and is widely distributed in China's inland waters. In Russia, Japan, Korea, Southeast Asia countries are distributed. Ornamental, Breeding Technology, Basic Overview, Breeding Introduction, Basic Introduction Basic Information Species Name River Clam Chinese Common Name Corbicula fluminea, yellow corbicula, cicada, sand snail, sand lah, fresh-water crayfish Latin Name Corbicula fluminea English Name Asian Clam Name: Mollusca, Class Valvulaceae, True Valvulinae, Family Corbicidae, Genus Clams American Clam River Clam Also known as yellow clams, golden arkshells and flat snails. Widely distributed in China, Korea, Japan, Southeast Asia and the Soviet Union. It is also found in the Soviet Union. It is produced in all rivers and lakes in China. Widely distributed in China's inland waters, rich in natural resources. They burrow in the soil surface layer under water, feeding on plankton, growing fast and reproducing strongly. In addition to natural resources, it is also suitable for artificial breeding. They are found in Russia, Japan, Korea and Southeast Asia. Environmental adaptation The river clam is a bivalve aquatic organism with a strong ability to adapt to the environment. It absorbs elements in the surrounding environmental medium and forms its shell of carbonate composition through the secretion of its mollusks. Therefore, the chemical composition of the shells of river corbicula should reflect the geochemical characteristics of the environmental medium. A comparative study of the composition of trace elements in the shells of river corbicula in the Nanming River, Guiyang, and the pollution of the river water showed that, with the deterioration of the river water quality, the content of Pb, Cd, Cu, Co, Fe, and Mn in the shells of the corbicula increased, with the largest increase in the rate of increase in Pb, which amounted to 285%, followed by Cd, Cu, Co, Fe, and Mn, which amounted to 127%, 121%, 84%, 48%, and 34%, respectively; on the contrary, the increase in Ni, Cd, and Mn, which amounted to 34%, and the increase in Ni, Cu, and Mn, which amounted to 34%. 34%; on the contrary, Ni, Na, and Zn were lower in the shells of river corbicula in the more polluted sections of the river, with Ni showing the largest decrease of 63%, followed by Na and Zn with 18% and 14%, respectively. The results of this preliminary study demonstrated that as the geochemical conditions of water quality change, river corbicula are indeed adjusting the composition of their shells to adapt to changes in the external environment, in which the changes in the content of trace elements such as Pb, Cd, Cu, Co, Fe, Mn, etc. are consistent with the changes in water pollution, and can be used to respond to the characteristics of the pollution in the environmental medium. Clams are rich in nutrients, the meat can be eaten fresh, Paleo dried and canned clams, can also be used as medicine. They can also be used as medicine. They are good for appetizer, breast milk, eyesight, urination, foot fungus, dampness and alcohol, as well as treating liver diseases and measles. River clams are natural bait for benthic fish and birds. Shell powder can be used as raw material for lime. Shell powder can be used as a raw material for lime. Clams are also the second intermediate host of the schistosomiasis, and raw or undercooked clams are susceptible to schistosomiasis. River clams reach sexual maturity in three months and can reproduce throughout the year. The gonadal period is from May to August, and the peak reproductive period is from May to June. The life span of river clams is about five years, and the best time to harvest and utilize them is between the ages of one and two. The best period for harvesting and utilizing clams is from the first to second year of age. Shells used for handicrafts should be more than 3 years old. River corbicula inhabits rivers, lakes, ditches, ponds and estuaries in brackish and freshwater waters where the substrate is mostly sand, sandy mud or mud. In the bottom of the water camp cave life, young corbicula habitat depth of 10-20 mm, large corbicula can dive 20-200 mm, to 20-50 mm distribution of the most. They feed on plankton (e.g. diatoms, green algae, eye worms, rotifers, etc.) filtered through the gills, which is a form of passive feeding. River clams are dioecious, but hermaphroditic individuals have also been found. River clams in the Fujian area reproduce at their peak from May to August each year, when large quantities of white slime-like material appear at the bottom of the riverbed. When the larvae of river corbicula end their planktonic life, they sink to the bottom and live benthically for 15-30 days, and then grow into 2 mm small corbicula in about 1 month, and 10 mm in 3 months, with the life span of the corbicula being about 5 years. Biological description The shells are medium-sized, round-bottomed and triangular, generally about 3 centimeters long, with shell height similar to shell length. Both shells are swollen. The top of the shell is high and slightly anteriorly oriented. The shell surface is glossy and the color varies according to the environment, often brownish yellow, yellowish green or blackish brown. Shell surface with rough ring ribs. Ligaments short, protruding outside the shell. The articulation is well developed. The left shell has 3 main teeth, and 1 each of anterior and posterior lateral teeth. Right shell with 3 primary teeth, 2 anterior and posterior lateral teeth each, with denticles listed above. Closed-shell muscle scar obvious, coat scar deep and conspicuous. One family of Bivalvia. Cosmopolitan distribution. Representing the genus Corbicula with small to medium-sized shells. Shell thick and firm, rounded or subtriangular in shape. Shell surface glossy, with concentric whorls of veins,, inner surface of shell white or greenish purple. The hinged part of the shell has three main teeth, the left shell has one anterior and one posterior lateral tooth, the right shell has two anterior and two posterior lateral teeth, the upper end of the lateral teeth is serrated. Foot large, ligulate. Dioecious or homozygous. Fertilized in the water, develops into a juvenile clam and then sinks to the bottom of the water for benthic life. It can be matured in about 3 months. There are also oviparous species. Inhabiting in fresh and salt water and fresh water. Meat flavor, high nutritional value, edible, but also fish, waterfowl natural feed. It is also a traditional Chinese medicine herb, with the effect of promoting lactation, improving eyesight, facilitating urination and removing dampness and poison. Shells can be forged lime. Clams are the second intermediate host of the echinostomatid trematode. The shells of the river corbicula commonly found in China are about 40 millimeters long and 30 millimeters high. The shell is thick and hard, slightly triangular in shape and slightly equal on both sides. The surface of the shell is yellowish green, blackish brown and black, glossy, and the inner surface of the shell is lilac, bright purple and porcelain-like glossy. It inhabits rivers and lakes. It is edible and also used as bait for fishes and birds, and as fertilizer for farmland. Morphological features The shells are medium-sized, round-bottomed triangular, generally about 3 cm long, with shell height similar to shell length. Both shells are swollen. The top of the shell is high and is slightly inclined to the front. The shell surface is glossy and the color varies according to the environment, often brownish yellow, yellowish green or blackish brown. Shell surface with rough ring ribs. Ligaments short, protruding outside the shell. The articulation is well developed. The left shell has 3 main teeth, and 1 each of anterior and posterior lateral teeth. Right shell with 3 primary teeth, 2 anterior and posterior lateral teeth each, with denticles listed above. Closed-shell muscle marks are obvious, and the coat marks are deep and conspicuous. Value Economic value River clam culture is suitable for both large and medium-sized water surface of lakes for releasing and multiplying, and also suitable for small-sized water surface or pond feeding and fertilizing culture. Cultivation of river corbicula low cost, high yield, easy to catch, can be the year of stocking the year harvest, the economic benefits of significant river corbicula meat flavor, nutrient-rich, in addition to fresh food, but also can be processed into dried corbicula, canned, frozen corbicula meat or pickled into salted corbicula. This is not only loved by people in the country, in Japan, South Korea and some countries in Southeast Asia, also generally loved by people. Provide exports of commercial river gauge, generally shell length 25 ~ 36 mm, shell height 22 ~ 33 mm, shell width 16 ~ 28 mm. Individual weight 4 to 7 grams, 160 to 220 per kilogram. River clams can also be used as farmland fertilizer. Application of crushed clam meat, crushed inkstone shells, acidic soil has an ameliorating effect. Medicinal value In recent years, with the increase in the export volume of river clams, the price of river clams has been rising. Japan and South Korea import tens of thousands of tons of fresh clams into China every year for sobering up and protecting the liver. River corbicula can not only be used as a traditional Chinese medicine, with appetizing, lactation, eyesight, diuretic, dehumidification, treatment of liver disease, measles fever, cough phlegm, alcohol and other efficacy, but also livestock and fish natural bait. Crushed clams and shells are mixed into feedstuffs to promote the growth and reproduction of poultry and livestock, and improve the egg production rate of poultry and milk production rate of livestock. River clams can also be used as fresh bait for some special aquatic products. In recent years, with the development of turtle, carp, eel and crab farming, people have begun to pay attention to the culture of river clams. Ornamental Clams can be kept as ornamental shellfish, and can be used as "filters" in the aquarium to purify the water and eat single-celled plants and microorganisms in the water, so they need to be supplied with chlorella and spirulina on a regular basis to satisfy their appetites. Cultivation Techniques Basic Overview River clams are rich in nutrients and easy to feed, so they can be used as bait for pond culture. Cultivation Introduction River clams are fertilized in vitro, and the eggs develop into facultative larvae. After completing the planktonic life stage, they begin to grow shells and sink to the bottom of the pond, burying the shells in the silt at the bottom of the pond, and sticking their straws in the water only to breathe and take in bait. Ponds for raising river clams should not be injected with pesticides and fertilizer water, which is most likely to cause the death of river clams. The water should not be excessively fertile. The substrate of the pond should be sandy. The depth of water is about 1 meter. Each acre can be stocked with 60 to 130 kilograms of river clam seedlings. River clams can't reproduce continuously in the pond, so the number of seedlings put in the second year can be reduced appropriately. The specification of river clam seedling is 800~4000/kg. If you buy clams from abroad, they can be transported in sacks or straw bales, and in order to reduce deaths on the way, they should be kept at a certain humidity and not piled up too thickly. Before stocking, the pond water should be drained and exposed to sunlight for 2-3 weeks before filling with water. When cultured in the pond, they should be fed soybean meal, wheat bran or rice bran, and chicken manure or other farmyard fertilizers can also be applied. The growth rate of river clams depends on the feeding conditions, the average weight of seedlings is about 0.11 grams, feeding 1.5 months can be four times the weight of 0.45 grams; 3 months up to 0.91 grams; 4 to 4.5 months up to 2.25 grams; 5 to 6 months up to 4 grams, 7 to 7.5 months up to 5.4 grams, the weight is equivalent to the original seedling 50 times, then you can be harvested. When catching river clams, you can use an iron rake with a net, and then use an iron sieve to sort out the size, and put the smaller individuals back into the original pool to continue rearing. River clams can also be mixed with bighead and silver carp and grass fish, but not with cyprinids and carp. Crushed clams are good bait for eels, and small clams can be fed directly.