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Taxonomy: Phylum: Chordata Class: Actinopterygii Order: Cypriniformes Family: Cyprinidae Identification: Juvenile Morphology Small fish lack spines in fins Metalarvae and early juvenile are similar to bighead carp (Hypophthalmichthys nobilis) but pectoral fin extends only to base of pelvic fin (as opposed to beyond in the pelvic fin in bighead) Silvery in color Adult Morphology Olive green coloration above lateral line and on back, silver below lateral line Deep body that is laterally compressed Eye positioned low on the head Terminal mouth Smooth keel on abdomen Gill rakers thin and numerous Dorsal fin origin posterior to pelvic fin base Distinguishing Characteristics Silver carp are unlikely to be confused with native cyprinids due to size and unusual position of the eye. They are most similar to bighead carp (H. nobilis) but have a keel that extends forward past pelvic fin base, lack the dark blotches characteristic of bighead carp and have highly branched gill rakers. General Biology: Behavior Fry form large schools Fry exhibit increased feeding activity in the afternoon and lowest activities at night Adults are known to leap out of the water when disturbed Diet Juveniles Studies on the diet of juvenile silver carp have shown variable results for the size at which young switch from a diet of zooplankton to phytoplankton. Below 114 mm will feed primarily on zooplankton and to a lesser degree phytoplankton Below 18.8 mm, feed primarily on rotifers and nauplii, between 18.8 and 26 mm, feed on cladocera and copepods and at greater than 26 mm, the diet was almost exclusively phytoplankton Adults Diet of adult silver carp remains controversial in the literature. Some studies have reported a diet composed exclusively of phytoplankton while others have reported diets high in detritus and zooplankton. Spataru and Gophen suggested this variation might be a reflection of the relative abundance of zooplankton and phytoplankton in the environment. Length of intestine can range from 7-15 times the body length Feed primarily on phytoplankton but also consume small zooplankton and detritus Will consume detritus and stir up bottom when phytoplankton numbers are low Diet is high in detritus "Versatile" omnivores- primarily phytoplankton and infrequently zooplankton Life Cycle: Growth May reach an age of 20 years May reach 44-60 lb Maturity 4-8 years in native range 60–70 cm TL Spawning Occurs at temperatures greater than 18 C and when water levels and flow increase due to the monsoon in native range Temperature is thought to be the primary cue Spawning is expected to occur in US waters due to similarities in spawning requirements with grass carp Eggs Bathypelagic Require current to stay suspended Minimum length of the spawning river is estimated to be 100 km and minimum current speed of 70 cm/s to keep eggs buoyant 3.2-4.7 mm diameter at maturity Juveniles Protolarvae 4.5-5.5 mm TL Habitat Characteristics: Preferred Environment Primarily found in large rivers in native range Temperature No data available Oxygen Can withstand low dissolved oxygen (3 mg/l) Salinity o Can tolerate brackish water (up to 12 ppt) Water Quality o May cause increased levels of turbidity Distribution: Native Range Large rivers of central and south Asia, eastern China, and USSR that flow into Pacific Ocean North American Distribution (Fuller et al.) Established: Silver carp have been recorded from the following states. However, only those with an asterisk (*) are states that have verified records of established, reproducing populations. Reproducing populations appear to be restricted to large river systems and have been documented in several rivers in Louisiana (see below), Horseshoe Lake (Illinois), and the Mississippi River. Reproduction may also be occurring in Missouri. Production cycle of Hypophthalmichthys molitrix Source | Citation | XML Search cultured species Cultured Aquatic Species Information Programme Hypophthalmichthys molitrix (Valenciennes, 1844) I. Identity V. Status and trends a. Biological features VI. Main issues b. Images gallery a. Responsible aquaculture practices II. Profile VII. References a. Historical background a. Related links b. Main producer countries c. Habitat and biology III. Production a. Production cycle b. Production systems c. Diseases and control measures IV. Statistics a. Production statistics b. Market and trade Identity Hypophthalmichthys molitrix Valenciennes, 1844 [Cyprinidae] FAO Names: En - Silver carp, Fr - Carpe argentée, Es - Carpa plateada Biological features Body laterally compressed and deep. Ventral keel extending from isthmus to anus. Head large. Eye small, on ventral side of head. Gillrakers sponge-like. Dorsal fin with 8 rays; no adipose fin. Anal fin with 13 to 15 rays. Lateral line with 83 to 125 scales. View SIDP Species fact sheet Images gallery Hypophthalmichthys molitrix Hypophthalmichthys molitrix Fish rearing pond area Seedling collection cages Spawning tanks Profile Historical background In the 5th Century B.C. in China, Fan Li described the ponds used, the selection of fish, and the breeding season of common carp, together with its sex ratio and growth rate. By the Han Dynasty (3 rd Century B.C. to 3rd Century A.D.), there were further developments in the production of common carp. In the Tan Dynasty (7 th –10th Century) there was a transition period from common carp culture to the rearing of grass carp, black carp, silver carp and bighead carp. From the 10th to the 12th Century, expansion in the production of these four cyprinids was even greater, and the feeding habits and relationship between the species became better known. Subsequently, there has been great progress in pond-fish culture in China from the monoculture of common carp to the polyculture of grass carp, black carp, silver carp and bighead carp. Since the 1950s, after a breakthrough in artificial breading, the culture of silver carp, as well as other carps, has spread tremendously into most areas of China. Silver carp has long been an important cultured species in China because: It is herbivorous and low in the food chain; feeds and fertilizers are therefore easily available at low cost. It can be polycultured with some other species, due to its specific habitat. Seeds are readily available from artificial breeding, without reliance on natural resources. Production management is simpler and the rearing period is shorter than for other carp species. In recent decades, silver carp have been widely introduced into European and Israeli waters for algal control and as a food source. Main producer countries Main producer countries of Hypophthalmichthys molitrix (FAO Fishery Statistics, 2006) Habitat and biology Silver carp is a freshwater species living in temperate conditions (6-28 °C) and its natural distribution is in Asia. This species requires static or slow-flowing water, as found in impoundments or the backwaters of large rivers. In its natural range, it is potamodromous, migrating upstream to breed; eggs and larvae float downstream to floodplain zones. While it is fundamentally benthopelagic, as an active species it swims just below the water surface and is well known for its habit of leaping clear of the water when disturbed.Silver carp are typical planktivores, the gillrakers being the main means of filtration. Silver carp consume diatoms, dinoflagellates, chrysophytes, xanthophytes, some green algae and cyanobacteria ('blue green algae'). In addition, detritus, conglomerations of bacteria, rotifers and small crustaceans are other major components of their natural diet. Silver carp spawn in late spring and summer, when the temperature of the water is relatively high. From April to August, either because of the rainstorms or the swollen upper reaches of streams and rivers, its broodstock are concentrated in spawning locations where conditions are favourable, and the current swift, complicated and irregular. Spawning temperature is generally between 18 ºC and 30 ºC, with an optimum of 22-28 ºC. The eggs of silver carp, like all Chinese carps, are non-adhesive. After spawning, the eggs begin to absorb water through the egg membrane and swell until its specific gravity is slightly greater than that of water, so they can stay at the bottom (in the case of static waters) or float halfway in mid-water (in flowing waters) until the fry hatch.
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