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For information on Wisconsin's rare vertebrate animals, contact:
Rich Staffen
Conservation Biologist
For information on Wisconsin's rare invertebrates, contact:
Jay Watson
Conservation Biologist

Blue Sucker (Cycleptus elongatus)



Blue Sucker (Cycleptus elongatus), listed as Threatened in Wisconsin, prefers large, deep rivers with moderate to strong currents over substrates of gravel or cobble. Spawning occurs from late April through early May.

State status

Status and Natural Heritage Inventory documented occurrences in Wisconsin

The table below provides information about the protected status - both state and federal - and the rank (S and G Ranks) for Blue Sucker (Cycleptus elongatus). See the Working List Key for more information about abbreviations. Counties shaded blue have documented occurrences for this species in the Wisconsin Natural Heritage Inventory database. The map is provided as a general reference of where occurrences of this species meet NHI data standards and is not meant as a comprehensive map of all observations.

Note: Species recently added to the NHI Working List may temporarily have blank occurrence maps.

Documented locations of Cycleptus elongatus in the Natural Heritage Inventory Database as of July 2015.
Summary Information
State StatusTHR
Federal Status in Wisconsinnone
State RankS2
Global RankG3G4
Tracked by NHIY

Species guidance

Note: a species guidance document is not available at this time. Information below was compiled from publication ER-091.

Identification: Elongate body with small head. Snout pointed, slightly bulbous at tip. Back and sides blue to blue black, belly whitish. Adult length: 2 feet (61cm).

Habitat: Prefer large, deep rivers and deeper zones of reservoirs, moderate to swift currents of narrow channels with gravel or rubble bottom.

State Distribution: Mississippi River drainage basin, lower St. Croix, Red Cedar, Chippewa, Black, LaCrosse and Wisconsin Rivers. Generally found as far upstream as the first dam. A map outlining Pre-1977 and 1997 to Present Distribution is available.

Phenology: Spawn from late April to early May at water temperatures of 50-60o F (10-15o C). Newly hatched young frequent shallow waters and are preyed on by fish-eating birds.

Diet: A gregarious fish, blue suckers are bottom feeders. Eat insects, insect larvae, crustaceans, plant material and algae.

Management Guidelines: Wisconsin populations of blue sucker represent some of the largest remaining in the upper Mississippi River basin, and therefore merit careful management. This species is intolerant to turbidity and pollution, so sources of pollution discharge and soil runoff within its range should be monitored and minimized.



Blue Sucker

Side view adult.

Photo by John Lyons, WDNR.

Blue Sucker

Side view adult.

Photo by John Lyons, WDNR.

Blue Sucker

Side view adult.

Photo by John Lyons, WDNR.

Blue Sucker

Close-up head.

Photo by John Lyons, WDNR.

Wildlife Action Plan

Wisconsin Wildlife Action Plan graphic

Natural community (habitat) associations

The table below lists the natural communities that are associated with Blue Sucker. Only natural communities for which Blue Sucker is "high" (score=3) or "moderate" (score=2) associated are shown. See the key to association scores for complete definitions. Please see the Wildlife Action Plan to learn how this information was developed.

Natural community Score
Warmwater rivers 3

Ecological landscape associations

The table below lists the ecological landscape association scores for Blue Sucker. The scores correspond to the map (3=High, 2=Moderate, 1=Low, 0=None). For more information, please see the Wildlife Action Plan.

This map shows the probability of Blue Sucker occurring in each of Wisconsin's Ecological Landscapes.  Actual scores can be found in the table to the left.

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Landscape-Community combinations of highest ecological priority*

Ecological priorities are the combinations of natural communities and ecological landscapes that provide Wisconsin's best opportunities to conserve important habitats for a given Species of Greatest Conservation Need. The 10 highest scoring combinations are considered ecological priorities and are listed below. More than 10 combinations are listed if multiple combinations tied for 10th place. For more information, please see the Wildlife Action Plan.

* Ecological priority score is a relative measure that is not meant for comparison between species. This score does not consider socio-economical factors that may dictate protection and/or management priorities differently than those determined solely by ecological analysis. Further, a low ecological priority score does not imply that management or preservation should not occur on a site if there are important reasons for doing so locally.

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Issues/threats and conservation actions

Conservation actions respond to issues or threats, which adversely affect species of greatest conservation need (SGCN) or their habitats. Besides actions such as restoring wetlands or planting resilient tree species in northern communities, research, surveys and monitoring are also among conservation actions described in the WWAP because lack of information can threaten our ability to successfully preserve and care for natural resources.

Threats/issues and conservations actions for rare animals

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Last revised: Thursday, December 22, 2022