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Grass carp

Grass carp

Characteristics

dark olive shading to brownish-yellow on the sides with a white belly and large scales, terminal mouth and torpedo shaped

Distribution

Grass carp Distribution

widely distributed throughout the state in ponds, man-made lakes, and large rivers

Foods

aquatic plants

State Record

61 pounds 8 ounces, 49 1/2 inches long- caught in May 1998 by Tyler Warner Greenfield, IA

Expert Tip

Details

White amur is an exotic minnow that was imported into the United States from eastern Asia for nuisance aquatic vegetation control in 1963. They were first brought into Iowa in 1973 by the Commission. White amur are now widely distributed throughout the state in ponds and man-made lakes, but it is not abundant in any location. Commercial fishermen report rare catches of white amur from the Mississippi and Missouri rivers.

White amur have an elongate, chubby body form that is torpedo shaped (terete). The terminal mouth is slightly oblique with non-fleshy, firm lips, and no barbels. The complete lateral line contains 40 to 42 scales. Broad, ridged pharyngeal teeth are arranged in a 2, 4-4, 2 formula. The dorsal fin has 8 to 10 soft rays, and the anal fin is set closer to the tail than most cyprinids. Body color is dark olive, shading to brownish-yellow on the sides with a white belly and large slightly outlined scales.

Grass carp have very specialized and restrictive riverine spawning requirements, which are not met in Iowa waters. Natural spawning is impossible in standing water, so the source of all fish for stockings is from artificial propagation. Growth of white amur is nearly unbelievable, young fish stocked in the spring at 8 inches will reach over 18 inches by fall, and adults often attain nearly 4 feet in length and over 40 pounds in weight. The state record is 43 pounds, 2 ounces from Red Haw Lake.

The diet of white amur consists of aquatic macrophytes, and since they are voracious feeders, they are utilized for control of nuisance aquatic vegetation in small lakes and pond. Controversy has surrounded grass carp since its importation, mainly from the past experience with its close relative -- common carp. However, research conducted at several locations across the nation, including Iowa, has shown that white amur do not have deleterious effects on native fishes and are an efficient means for the biocontrol of nuisance aquatic vegetation.


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Present in these Iowa water bodies:

Lake/Stream County Location Acres/Length
Coralville Reservoir Johnson 4 miles north of Iowa City 5280.00
Lake Manawa Pottawattamie Southwest edge of Council Bluffs 747.00
Pleasant Creek Lake Linn 4 miles North of Palo 401.00
Otter Creek Lake Tama 6 miles Northeast of Toledo 74.00
Greenfield Lake Adair 1 mile southwest of Greenfield 56.00
Hannen Lake Benton 4 miles Southwest of Blairstown 38.00
Willow Lake Harrison 5 1/2 mile west of Woodbine 26.00
Nodaway Lake Adair 2 miles southwest of Greenfield 25.00
Central Park Lake Jones 2 miles West of Center Junction 24.00

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