Grass Carp

Grass Carp, photo courtesy of Noel M. Burkhead, copyright Noel M. Burkhead, USGS, Nonindigenous Aquatic Species, http://nas.er.usgs.gov/taxgroup/fish/default.aspx.

Characteristics

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

Distribution

Grass Carp Distribution

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.

Foods

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. They are not effective in controlling filamentous algae (moss) or duckweed problems in ponds.

State Record

85 pounds 8 ounces, 48 inches long- caught in May 2007 by Jesse Lane 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 Iowa Conservation Commission, however, the DNR no longer stocks these fish into public waters. White Amur are now widely distributed throughout the state in ponds and man-made lakes, but it is not abundant in any location. The White Amur is primarily a big river fish and has been found in the Mississippi and Missouri rivers. As it often escapes from ponds and impoundments where it is stocked, the White Amur has also occasionally been found in Iowa’s interior rivers and streams, including streams in the Skunk, lower Iowa, Maquoketa and Winnebago river watersheds.

The White Amur is most often found in large rivers but is stocked in impoundments, ponds and lakes. It prefers swift, warm waters with slack current and aquatic vegetation. In its native habitat, White Amur prefer turbulent reaches of large rivers. Some investigators voice concern because the White Amur’s voracious appetite for aquatic vegetation may lead to the destruction of suitable habitat for many native fish and waterfowl. 

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 specialized and restrictive riverine spawning requirements, but young fish have been sampled in Iowa rivers. Natural spawning is impossible in standing water. 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 85 pounds 8 ounces from Greenfield Lake.

The diet of White Amur consists of aquatic macrophytes, and since they are voracious feeders, they are stocked by private individuals for control of nuisance aquatic vegetation in private lakes and ponds.  Research conducted in Iowa has shown that White Amur have deleterious effects on water quality and fish habitat, and thus are no longer stocked by the Iowa DNR in public water bodies.

Recent stream sampling information is available from Iowa DNR's biological monitoring and assessment program.

Sources:

Harlan, J.R., E.B. Speaker, and J. Mayhew. 1987. Iowa fish and fishing. Iowa Conservation Commission, Des Moines, Iowa. 323pp.

Loan-Wilsey, A. K., C. L. Pierce, K. L. Kane, P. D. Brown and R. L. McNeely. 2005. The Iowa Aquatic Gap Analysis Project Final Report. Iowa Cooperative Fish and Wildlife Research Unit, Iowa State University, Ames.

Photo Credit: photo courtesy of Noel M. Burkhead, copyright Noel M. Burkhead, USGS, Nonindigenous Aquatic Species.


Return
Present in these Iowa water bodies:
Lake/Stream County Location Acres/Length
Pool 18, Mississippi River Louisa Amenities listed are for the Toolsboro Ramp. The ramp at Toolsboro is paved but the road to the ramp is gravel. There is some shore fishing along the parking area and at the outlet of Lake Odessa. Amenities vary by location in pool 18 13300.00
Pool 16, Mississippi River Scott The amenities list are for Buffalo Shores campground in Buffalo, Iowa. Amenities at other locations in Pool 16 vary by location. 13000.00
Pool 17, Mississippi River Muscatine Amenities list for Muscatine City Ramp. This ramp is located in downtown Muscatine. Amenities vary by location in Pool 17. 7580.00
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
Little Wall Lake Hamilton 1 1/2 miles south of Jewell 249.00
West Nishnabotna River Fremont 121.00
Iowa River (Marshalltown to Coralville Lake) Iowa This stretch is located in Marshall, Tama, the SW corner of Benton, Iowa, and Johnson County. A popular access is at the Hwy 21 Access, which is part of the Iowa River Corridor Wildlife Area, just south of Belle Plaine. 104.00
Otter Creek Lake Tama 6 miles Northeast of Toledo 74.00
Missouri River (Sioux City to Little Sioux) Harrison Chris Larsen Park: 1280 Larsen Park Road/Sioux City, IA. Located on the Sioux City riverfront along the Missouri River. Larsen Park offers 110 acres on the Sioux City Riverfront. Managed by the City of Sioux City. 64.00
Missouri River (Council Bluffs to state line) Fremont Lake Manawa State Park: 1100 South Shore Drive/Council Bluffs, IA 51501 phone: 712-366-0220. Managed by the Iowa Department of Natural Resources Lake Manawa State Park has boat ramps on the Missouri River within the park. 61.00
Lake Smith Kossuth 3 miles north of Algona 59.00
Little Sioux River (Correctionville to Missouri R) Harrison Little Sioux Park, 2 miles SW of Correctionville, Woodberry County Conservation Board 57.00
Cedar River (La Porte City to Cedar Rapids) Linn This stretch is located in Benton and Linn County. A popular river access is in the Dudgeon Lake Wildlife Area right of Hwy 150 on the North side of Vinton. 56.00
Greenfield Lake Adair 1 mile southwest of Greenfield 56.00
Cedar River (Cedar Rapids to Moscow) Cedar This stretch is found in Linn and Cedar County. A popular access is found in Palisades State Park which is on Hwy 30 between Cedar Rapids and Mount Vernon. 55.00
Missouri River (Little Sioux to Council Bluffs) Pottawattamie Wilson Island State Recreation Area: 32801 Campground Lane/Missouri Valley, IA 51555 phone-712-642-2069. Managed by the Iowa Department of Natural Resources, Wilson Island Recreation Area has 544 acres along the Missouri River near Missouri Valley Iowa. 53.00
Hannen Lake Benton 4 miles Southwest of Blairstown 38.00
Beaver Lake Dallas 1 1/2 miles north of Dexter 34.00
Meadow Lake Adair 6 miles northeast of Greenfield 34.00
Iowa River (Coralville Lake to River Junction) Johnson This stretch is located in Johnson County. A popular access is the Tailwater East Ramp located right below the Coralville Lake Dam, East of North Liberty and Coralville. 29.00
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
Mariposa Lake Jasper 5 miles northeast of Newton 17.90
Ankeny Lake (DMACC) Polk Ankeny, DMACC Campus 14.00
Arrowhead Pond Pottawattamie 1 1/2 miles southeast of Neola 14.00
Cocklin Fish Farm Cass 2 miles north of Griswold 8.00