Plants and Animals

Polyodon spathula Paddlefish

Key Characteristics

Paddlefish are unique fish with a long paddle-shaped snout that is about 1/3 the length of the body. These fish have small eyes, numerous slender gill rakers, a large tapering operculum flap that extends to the pelvic fins, and a deeply forked abbreviate heterocercal caudal fin. This is one of the largest freshwater fish attaining a size of over 2.2 m.

Status and Rank

US Status:
State Status: X - Presumed extirpated (legally 'threatened' if rediscovered)
Global Rank: G4 - Apparently secure
State Rank: SX - Presumed extirpated

Occurrences

CountyNumber of OccurrencesYear Last Observed

Information is summarized from MNFI's database of rare species and community occurrences. Data may not reflect true distribution since much of the state has not been thoroughly surveyed.

Habitat

In Michigan, paddlefish occurred in slower-moving waters of river side channels, in protected bays, and eddies of tailwaters below dams. Spawning occurs on shallow gravel bars.

Natural Community Types

  • Headwater stream (1st-2nd order), pool
  • Inland lake, pelagic, midwater
  • Mainstem stream (3rd-4th order), pool
  • River (5th-6th order), pool

For each species, lists of natural communities were derived from review of the nearly 6,500 element occurrences in the MNFI database, in addition to herbarium label data for some taxa. In most cases, at least one specimen record exists for each listed natural community. For certain taxa, especially poorly collected or extirpated species of prairie and savanna habitats, natural community lists were derived from inferences from collection sites and habitat preferences in immediately adjacent states (particularly Indiana and Illinois). Natural communities are not listed for those species documented only from altered or ruderal habitats in Michigan, especially for taxa that occur in a variety of habitats outside of the state.

Natural communities are not listed in order of frequency of occurrence, but are rather derived from the full set of natural communities, organized by Ecological Group. In many cases, the general habitat descriptions should provide greater clarity and direction to the surveyor. In future versions of the Rare Species Explorer, we hope to incorporate natural community fidelity ranks for each taxon.

Management Recommendations

Many factors caused the extirpation of paddlefish in Michigan, including over fishing, habitat inundation, channelization, dams, and flow alterations. This species is particularly susceptible to over harvest due to their predictable spawning runs in the tailwaters below dams. Increased pollution and siltation are also substantial threats affecting paddlefish populations.

Active Period

Spawning from third week of April to fourth week of May

Survey Methods

Species are highly mobile and make extensive movements within a system (Jennings 2000).

Seines

Survey Period: From first week of May to first week of September

Gill net

Survey Period: From first week of May to first week of September

Trammel net

Survey Period: From first week of May to first week of September

References

Survey References

  • Murphy, B.R. and D.W. Willis, eds. 1996. Fisheries Techniques, 2nd ed. American Fisheries Society, Bethesda. 732pp.

Technical References

  • Bailey, R.M., W.C. Latta, and G.R. Smith. 2004. An Atlas of Michigan Fishes. Museum of Zoology, University of Michigan, No. 192, Ann Arbor. 215p.
  • Hubbs, C.L. and K.F. Lagler. 2004. Fishes of the Great Lakes region, revised edition. Rev.ed. G.R. Smith. The University of Michigan Press, Ann Arbor MI. 276pp.
  • Jennings, C.A. and S.J. Zigler. 2000. Ecology and biology of paddlefish in North America: historical perspectives, management approaches, and research priorities. Reviews in Fish Biology and Fisheries 10: 167-181.
  • NatureServe. 2005. NatureServe Explorer: An online encyclopedia of life [web application]. Version 4.5. NatureServe, Arlington, Virginia. Available http://www.natureserve.org/explorer.
  • Scott, W.B. and E.J. Crossman. 1973. Freshwater fishes of Canada. Bulletin 184, Fisheries Research Board of Canada, Ottawa. 966pp.
  • Smith, P.W. 1961. The amphibians and reptiles of Illinois. Illinois Natural History Survey, Carbondale. Bulletin No. 28. 298 pp.