Description: Another 'Asian carp', the grass carp is native to eastern Asia, ranging from the Amur River in China and Siberia to south of the West River in China and Thailand. It was first introduced in the United States in Arkansas in 160s and has since spread to 34 states.
Identification: Gray to brassy green above, white to yellow below, with clear to gray-brown fins. Body slender and fairly compressed; wide head and terminal mouth. Scales are large and have dark edges with a black spot at the base. Dorsal fin origin in front of the pelvic fin origin. Pharyngeal teeth, elongate with prominent parallel grooves on grinding surfaces and often hooked at the tip. On average, 36 to 48 inches but can reach up to 60 inches.
Habitat: Native range in Asia - backwaters and floodplain lakes of large rivers. United States - adapted well to small ponds; often sold for control of rooted aquatic vegetation.
Reproduction: Grass carp spawn in flowing water because oxygen-rich water is essential to their reproductive success, ensuring the eggs are suspended until they hatch.
Impact and Damage: The escape of diploid grass carps from experiments in Lake Conroe, as well as illegal stockings of grass carp, have created opportunities for the species to spread. Introduced as a solution to aquatic weed problems, they have harmed ecosystems by removing vegetation that native fishes, waterfowl and other species rely on. They feed on a wide range of food including algae, invertebrates and vertebrates to the point of harming several native plant and animal species.
Monitoring and rapid response: To control the spread of grass carp, most states only permit stocking of triploid populations, and some states do not allow stocking of grass carp at all. States such as Texas also mandate that anglers must remove the intestines of any grass carp they catch.
Credits: The information contained in this factsheet was provided by the Shedd Aquarium. Photos (T-B) courtesy of the Michigan Sea Grant, BioPix: JC Schou, and the Illinois River Biological Station.