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Blue Sucker

Blue Sucker, photo courtesy of Konrad P. Schmidt, copyright Konrad P. Schmidt


A slender, dark-colored sucker with a small head and a long, sickle-shaped dorsal fin. Back and sides blue-black or dark olive with brassy reflections and a white belly. Breeding males are very dark and have small tubercles over most of the head, body and fins. Eyes small and closer to rear margin of gill cover than to tip of snout. Mouth small, horizontal, and distinctly overhung by snout. Lips covered with numerous wart-like papillae. Lateral line complete, containing 55 to 58 scales. Body length about 4 to 5 times greater than body depth. Fins dusky or black, dorsal fin with 28 to 33 rays.


Blue Sucker Distribution

The Blue Sucker rarely occurs in fish collections in Iowa, but its distribution is rather widespread in The Mississippi and Missouri Rivers and in the lower reaches of their larger tributaries. It has never been documented in the upper reaches of our interior streams. Abundance has declined since the early 1900's, but the species remains unprotected.


Consists largely of aquatic insects and their larvae, crustaceans and plant material including algae, which they glean from the bottom in the typical vacuum-like manner.

State Record

15 lbs. 6 oz.; 33.25 in. - Iowa River, Johnson County, 4/11/2011 - Steven Jones, Iowa City

Expert Tip

These fish will mostly likely be found at the lower end of tributaries to the Mississippi and Missouri Rivers.


Blue Suckers prefer the deep, large rivers and usually occupy the narrow chutes and swift channels where the current is moderate to swift over a bottom of gravel, sand and rocks. They are tolerant of high turbidity. Past records show this species made important spring runs up the Cedar River to the dam at Palisades State Park near Cedar Rapids, but at present they have nearly disappeared from this river stretch.

The Blue Sucker is most widely distributed in the Missouri and Mississippi River and can occasionally be found in the lower reaches of their tributaries. There is no record of Blue Suckers ever being caught in the upper reaches of Iowa’s interior streams. Because it is virtually invulnerable to normal collecting most of the year, the Blue Sucker is likely more abundant and widespread than is reported.

The Blue Sucker prefers the swift waters of big rivers overlying firm substrates such as sand, gravel or rock. Researchers have found that it also inhabits the channels of deep lakes and found that it prefers clear channels and pools with moderate current. In Missouri the Blue Sucker is typically found where the channel is constricted by natural or artificial obstructions, including bedrock or boulder riffles, the tailwaters of dams, wing dikes and bridge abutments. As a migratory species, the Blue Sucker has declined in abundance since 1900 as dam construction has increased. Dams have also limited the Blue Sucker’s habitat by decreasing current velocity and increasing siltation. Due to its sensitivity to heavy pollution and siltation, the Blue Sucker can serve as a guide to judging water quality.

Little is known about the Blue Sucker life history in Iowa. Fisheries literature reveals that an upstream spawning migration into riffle areas takes place in late April to early May at water temperatures ranging from 50 to 60 degrees F. They are gregarious spawners broadcasting the semi-adhesive eggs over gravel and rubble bottoms directly in the current. Sexual maturity occurs at ages 2 and 3. The duration of egg incubation and fecundity is unknown.

Growth of this species has been documented in the Cedar River in Wisconsin. Twelve specimens in the study that ranged from 4 to 11 years averaged 3.5, 8.9, 14.8, 19.2, 21.1, 22.6, 24.0, 25.2, 26.2, 27.2, and 28.6 inches at the end of each year of life. Food of the Blue Sucker consists largely of aquatic insects and their larvae, crustaceans and plant material including algae, which they glean from the bottom in the typical vacuum-like manner.

Like the other sucker species in Iowa, these fish have minimal importance to anglers. It is viewed as vulnerable according to the Iowa Wildlife Action Plan, but it not on the threatened or endangered species lists in Iowa (571 IAC 77.2(2) (2015)).

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


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

Iowa Department of Natural Resources, Iowa Wildlife Action Plan

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

Pflieger, W.L. 1997. The fishes of Missouri. Missouri Department of Conservation, Jefferson City, Missouri. 372 pp.

Photo Credit: photo courtesy of Konrad P. Schmidt, copyright Konrad P. Schmidt


Present in these Iowa water bodies:

Lake/Stream County Location Acres/Length
Boyer River (Dunlap to Missouri River) Pottawattamie 34.00