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<br /> <br />34 Foreign Nonindigenous Carps and Minnows (Cyprinidae) in the U.S.-A Guide to their Identification <br /> <br />Spawning Requirements <br />of Chinese Carps <br />(Silver, Grass, Bighead, and Black Carps) <br /> <br />In general, the four species of Chinese carps require large riverine <br />environments for successful reproduction (Nico and others, 2005). Both migration <br />and spawning activities are initiated in response to a combination of physical and <br />hydrologic changes, such as increasing water levels, flows, and water temperature <br />(Yih and Liang, 1964; Jennings, 1988; Opuszynski and Shireman, 1995). However, <br />the importance of anyone factor may vary among different regions (Nico and <br />others, 2005). <br /> <br />Spawning grounds are usually located in river reaches characterized by <br />turbulent or whirlpool-like flow, often in the vicinity of islands or stream junctions <br />(Yih and Liang, 1964; Nico and others, 2005). Reported current velocities of <br />spawning areas in China ranged from 0.33-0.90 m/s with temperatures ranges of <br />19.2-29.0 DC (Yih and Liang, 1964). <br /> <br />The appropriate environment, particularly with regard to water turbulence <br />and higher water temperatures, is considered critical because it apparently <br />stimulates spawning and is necessary for successful early development of eggs <br />(Nico and others, 2005). The eggs of Chinese carps are semibuoyant and are carried <br />by currents until they hatch (Soin and Sukhanova, 1972). <br /> <br />Introduced populations have been known to successfully reproduce in <br />artificial canals of sufficient length that somewhat mimic the flow of natural rivers, <br />such as the Kara Kum Canal in Turkmenistan (Aliyev, 1976; Nico and others, <br />2005). Eggs or larvae of Chinese carps found in reservoirs suggest the possibility <br />of spawning in these habitats (Tang, I 960a,b ). Nevertheless, uncertainty remains as <br />to whether spawning occurred within the reservoir or in a connected stream (Nico <br />and others, 2005). If spawning does occur in such artificial habitats, it could have <br />been triggered by fluctuations in water levels or wave actions that mimicked natural <br />riverine environments. <br />