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Contact information
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

Paddlefish (Polyodon spathula)



Paddlefish (Polyodon spathula), listed as a Threatened Species in Wisconsin, prefers large rivers and their lakes. It spawns over mud or gravel in early spring during high flows, early-May through early-June.

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 Paddlefish (Polyodon spathula). 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 Polyodon spathula in the Natural Heritage Inventory Database as of July 2015.
Summary Information
State StatusTHR
Federal Status in Wisconsinnone
State RankS2
Global RankG4
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: Peculiar paddle-shaped snout, large size, shark-like tail. Grey to blue black dorsally and laterally, whitish ventrally. Also referred to as spoonbill catfish. Adult length may exceed 5 feet (1.5 m) including paddle.

Habitat: Prefer large rivers and their lakes. Widespread at variable depths. Paddlefish normally inhabit deep water, but during summer can be found near the surface.

State Distribution: Historic records occur for the Mississippi, St. Croix, Chippewa, Red Cedar and Wisconsin Rivers, and also in lower portions of the Baraboo River. Surveys indicate that populations have disappeared above the Prairie du Sac dam on the Wisconsin River. A map outlining Pre-1977 and 1997 to Present Distribution is available.

Phenology: Spawning occurs in early spring. Eggs hatch in 12-14 days. Mature adults probably do not spawn every year.

Diet: Like a plankton net, the paddlefish's large mouth with fine strains filters small crustaceans, algae, ephemerid larvae and mayflies. They also occasionally feed from bottom. It has been suggested that the paddle-like bill senses plankton concentration levels.

Management Guidelines: Damming of large rivers has eliminated much of the paddlefish's spawning habitat by controlling spring flooding and keeping water within its banks. The paddlefish is heavily parasitized by lampreys (Ichthyomyzon spp.). Artificial propagation of this species has had limited success in other states. Normal electro-shocking methods may result in mortality. A modification of the Kolz (1989) shocking method has proven effective under limited testing. Snagging by anglers also results in mortality and is sometimes done unintentionally. Posting signs to educate anglers about the legal status, life history, and protection of this rare species may help reduce unnecessary take.




The paddlefish is one of a large number of rare aquatic organisms that inhabit the Lower Wisconsin River.

Photo by John Lyons, WDNR.


Side view adult.

Photo by John Lyons, WDNR.


Side view adult.

Photo by John Lyons, WDNR.


A big river species found mostly in the lower stretches of the Wisconsin, Chippewa, and St Croix Rivers, and in the Mississippi River.

Photo © Timothy Knepp.

Wildlife Action Plan

Wisconsin Wildlife Action Plan graphic

Natural community (habitat) associations

The table below lists the natural communities that are associated with Paddlefish. Only natural communities for which Paddlefish 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.

Ecological landscape associations

The table below lists the ecological landscape association scores for Paddlefish. 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 Paddlefish 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