Gizzard Shad

Gizzard Shad, photo courtesy of Konrad P. Schmidt, copyright Konrad P. Schmidt.

Characteristics

Gizzard shad exhibit the typical herring body shape with a deep, oblong body that is strongly compressed laterally. Color ranges from bright silvery blue on the back, silvery sides and a dusky white on the belly. A dark shoulder spot is common on younger fish but may be absent from adults. Maximum size range in Iowa is about 9-14 inches.

Distribution

Gizzard Shad Distribution

The gizzard shad is common to abundant in many Iowa waters and has been collected statewide except for a few northwest locations. The fish has been collected in all of the major river systems, large reservoirs, and many of the man-made lakes.

Foods

The species is an omnivorous filter feeder taking both phytoplankton and zooplankton, which are then ground in the gizzard-like section of the gut. Some bottom material is often ingested while feeding; hence, the name mud shad or mud feeder.

State Record

State Records are not documented for non-game species.

Expert Tip

Shad make great bait for catching channel catfish!

Details

The Gizzard Shad is one of the most widespread and abundant of Iowa’s fishes. With the exception of the far northern central part of the state, it has been found in all the state’s major rivers systems, large reservoirs and man-made lakes. It is found throughout the Mississippi River as well as in parts of the Missouri River.  

Gizzard shad exhibit the typical herring body shape with a deep, oblong body that is strongly compressed laterally. Color ranges from bright silvery blue on the back, silvery sides and a dusky white on the belly. A dark shoulder spot is common on younger fish but may be absent from adults. The front of the head is rounded with a sub-terminal mouth. Teeth are absent. There are about 190 rakers on the lower limb of the first gill arch. The eyes have adipose eyelids with vertical slits. Body scales are cycloid with no lateral line present. The ventral scales are keeled. Dorsal fin rays number 10 to 12 with the last ray elongated into a thin whip-like filament. This fin is inserted slightly behind the pelvic fin. An auxiliary process is present at the base of the pelvic fin. The anal fin has 27 to 34 rays, and the caudal fin is deeply forked.

The Gizzard Shad is common in lakes, oxbows, impoundments, sloughs and large rivers with basic or low gradients, but reaches greatest abundance in waters where fertility and productivity are high. It avoids high gradient streams and rivers in the mountains and rivers without large, permanent pools, but can tolerate moderately turbid and occasionally even brackish or salt waters. The Gizzard Shad prefers living in open water, at or near the surface. In Iowa, this species is synonymous with mud, preferring sluggish, soft-bottomed waters. In Missouri, the Gizzard Shad is usually found in the deep calm waters of natural lowland lakes, ponds, artificial impoundments, or in the pools and backwaters of streams. It has benefited from the construction of upstream reservoirs in the larger rivers in its range. The Gizzard Shad spawns in shallow backwaters or near the shore. The fish are random, nocturnal group spawners with no care given to the young. Eggs are released near the surface of the water from late April or early May to early August at 50 to 70 degrees F. The eggs are adhesive and sink. The females are prolific, producing up to 400,000 eggs that are about .03 inch in diameter.

The species is an omnivorous filter feeder taking both phytoplankton and zooplankton, which are then ground in the gizzard-like section of the gut. Some bottom material is often ingested while feeding; hence, the name mud shad or mud feeder. Shad are intermediate hosts for several species of the glochidiad stages of mussels and in that respect have economic importance in the perpetuation of freshwater mussels with commercial value.

Shad commonly reach 4 inches in length during the first year of life. The maximum size range in Iowa is about 9 to 14 inches.

Gizzard Shad have little value as a food-fish and are seldom taken by hook-and-line. Its flesh, and particularly the gizzard-like stomach, are occasionally fermented for use as catfish bait. Dense shad populations provide considerable forage as young for other predatory fishes, and their schooling behavior during the first year make them easy prey for larger fish. Some controversy surrounds this forage value, however, as shad quickly outgrow the vulnerable forage size and rapidly assume pest levels in some closed watersheds or when predator populations are insufficient to control their numbers. Evidence is quite strong that shad compete with young bluegill for food items, and when populations reach very dense levels, bluegill survival is inevitably lowered. At that time, eradication of the entire fish population and game fish species restocking, particularly in small lakes seems to be the only alternative in restoring acceptable fishing. Massive die-offs of young and yearling shad are commonly reported after spring ice-out as a result of their susceptibility to fluctuating water temperatures.

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 Konrad P. Schmidt, copyright Konrad P. Schmidt.


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Present in these Iowa water bodies:
Lake/Stream County Location Acres/Length
Pool 19, Mississippi River Lee Amenities listed are at City of Ft. Madison boat ramp. Amenities vary by location in Pool 19 33500.00
Red Rock Reservoir Marion 4 miles north of Knoxville 15250.00
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
Saylorville Reservoir Polk North edge of Des Moines 4970.00
Big Timber Complex Louisa Two miles south of Muscatine, IA off of X-61/Stewart Rd. 1252.00
Lake Macbride Johnson 4 miles West of Solon 940.00
Big Creek Lake Polk 2 miles north of Polk City 814.00
DeSoto Bend at DeSoto National Wildlife Refuge Harrison 5 miles west of Missouri Valley at DeSoto National Wildlife Refuge 811.00
Lake Manawa Pottawattamie Southwest edge of Council Bluffs 747.00
Pleasant Creek Lake Linn 4 miles North of Palo 401.00
Roberts Creek Lake Marion 6 miles northeast of Knoxville 288.00
Blue Heron Lake (Raccoon River Park) Polk southwest of West Des Moines; Raccoon River Park 232.00
Easter Lake Polk southeast edge of Des Moines 179.10
Ada Hayden Heritage Park Lake Story North side of Ames, west of Grand Avenue/Highway 69. 137.00
East Nishnabotna River Fremont Red Oak city limits has river access and hard surface boat ramp 123.00
West Nishnabotna River Fremont 121.00
Grays Lake Polk Fleur Drive, Des Moines 96.00
Sand Lake Marshall On the Northeast edge of Marshalltown 95.00
RAPP Park Lakes Page north edge of Shenandoah 95.00
Terry Trueblood Lake Johnson 1.5 miles south of Hwy 6 on Gilbert Street in Iowa City. 90.00
Cedar Lake Madison 2 miles northeast of Winterset 90.00
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
Lower Pine Lake Hardin 1/2 mile east of Eldora 62.00
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
Atlantic Quarry Pond 3 Cass 60.90
Des Moines River (Stratford to Saylorville Lake) Polk The Highway 30 Access is in the middle of this river section and is located 3 miles west of Boone on the north side of Highway 30. 57.00
Little Sioux River (Correctionville to Missouri R) Harrison Little Sioux Park, 2 miles SW of Correctionville, Woodberry County Conservation Board 57.00
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
Des Moines River (Saylorville to Red Rock) Marion A mid-section access point for this stretch of river is at the Pleasant Hill Boat Ramp. This ramp is located on SE Vandalia Drive immediately east of Highway 65. 50.00
Folsom Lake Mills 2 miles west of Glenwood 45.00
Copper Creek Polk North side of University Ave. in Pleasant Hill along Four Mile Creek. 42.50
Prairie Park Fishery Linn 1.5 miles SSE of Cargill on Otis Road, along the Cedar River in Cedar Rapids 42.00
Des Moines River (Farmington to Keokuk) Lee Redwing Access : 3941 Valley Road just west of Keokuk. 35.00
Boyer River (Dunlap to Missouri River) Pottawattamie Highway 30 bridge in Woodbine. Easting 275280 Northing 4623540 34.00
Petersons Pit, West Story 4 miles northeast of Ames 33.00
North Raccoon River (Perry to Van Meter) Dallas A mid-section access point for this section of river is at the Highway 44 Access 4 miles west of Dallas Center. 31.00
Iowa River (Columbus Junction to Mississippi R) Louisa Cappy Russell Access : West of Oakville 6444 County Road X-71, Oakville, IA 52646 30.00
Jay Carlson Pit (west) Boone 3 miles west of Boone 25.60
Banner Lake (south) Warren 4 1/2 miles north of Indianola 24.00
Banner Lake (north) Warren 4 1/2 miles north of Indianola 16.00
Seminole Valley Park Lakes Linn Along the Cedar River in Northwest Cedar Rapids 12.00