The Nonindigenous Occurrences section of the NAS species profiles has a new structure. The section is now dynamically updated from the NAS database to ensure that it contains the most current and accurate information. Occurrences are summarized in Table 1, alphabetically by state, with years of earliest and most recent observations, and the tally and names of drainages where the species was observed. The table contains hyperlinks to collections tables of specimens based on the states, years, and drainages selected. References to specimens that were not obtained through sighting reports and personal communications are found through the hyperlink in the Table 1 caption or through the individual specimens linked in the collections tables.

Ichthyomyzon unicuspis
Ichthyomyzon unicuspis
(Silver Lamprey)
Native Transplant

Copyright Info
Ichthyomyzon unicuspis Hubbs and Trautman, 1937

Common name: Silver Lamprey

Taxonomy: available through www.itis.govITIS logo

Identification: Trautman (1981); Smith (1985); Page and Burr (1991); Etnier and Starnes (1993); Pflieger (1997).

Size: 39 cm.

Native Range: St. Lawrence-Great Lakes basin from Quebec to southwestern Ontario and south through upper Mississippi and Ohio River basins to central Tennessee. Nelson River, Manitoba; Missouri River, Nebraska; and Mississippi River, Mississippi (Page and Burr 1991). Not reported from Arkansas (Robison and Buchanan 1988).

Native range data for this species provided in part by NatureServe NS logo
Hydrologic Unit Codes (HUCs) Explained
Interactive maps: Point Distribution Maps

Nonindigenous Occurrences:

Table 1. States with nonindigenous occurrences, the earliest and latest observations in each state, and the tally and names of HUCs with observations†. Names and dates are hyperlinked to their relevant specimen records. The list of references for all nonindigenous occurrences of Ichthyomyzon unicuspis are found here.

StateFirst ObservedLast ObservedTotal HUCs with observations†HUCs with observations†
NY197419963Hudson-Hoosic; Lower Hudson; Middle Hudson
VT198519962Lake Champlain; Mettawee River

Table last updated 6/19/2024

† Populations may not be currently present.

Ecology: Silver Lamprey inhabit large streams and lakes, where the parasitic adults can find large fish hosts upon which to attach and feed. Spawining in Silver Lamprey occurs in May-June, when water temperatures reach 50°F, in shallow streams and tributaries on gravel riffles (Smith 1985). After hatching, ammocoetes burrow into mud or loose sediments and remain there for 4-7 years, feeding on zooplankton and detritus (Smith 1985). After emergence and transformation Silver Lampreys travel downstream to larger rivers or lakes to enter parastic adult stage, which lasts for 1-2 years (Smith 1985; Ross 2001).

Means of Introduction: Canal connection. Probably gained access from Lake Champlain to the Hudson River via the Champlain-Hudson Canal (Smith 1985; Mills et al. 1997).

Status: Established in New York.

Impact of Introduction: Unknown, however, this species is parasitic and feeds on trout, whitefish, smelt, pike, white sucker, black buffalo, brown bullhead, carp, rock bass, walleye, paddlefish, sturgeons, and gars (Smith 1985).

Remarks: None.

References: (click for full references)

Etnier, D.A., and W.C. Starnes. 1993. The fishes of Tennessee. The University of Tennessee Press, Knoxville, TN.

Mills, E.L., M.D. Scheuerell, J.T. Carlton, and D.L. Strayer. 1997. Biological invasions in the Hudson River basin. New York State Museum Circular 57:1-51.

Page, L. M., and B. M. Burr. 1991. A field guide to freshwater fishes of North America north of Mexico. The Peterson Field Guide Series, volume 42. Houghton Mifflin Company, Boston, MA.

Pflieger, W. 1997. The fishes of Missouri. Missouri Department of Environmental Conservation, Jefferson City, MO.

Robison, H.W., and T.M. Buchanan. 1988. The fishes of Arkansas. University of Arkansas Press, Fayetteville, AR.

Ross. S.T. 2001. The inland fishes of Mississippi. University Press of Mississippi, Jackson, MS.

Smith, C.L. 1985. The inland fishes of New York State. New York State Department of Environmental Conservation, Albany, NY.

Trautman, M.B. 1981. The fishes of Ohio. Ohio State University Press, Columbus, OH.

Whitworth, W. R. 1996. Freshwater Fishes of Connecticut. State Geological and Natural History Survey of Connecticut, Bulletin 114.

Other Resources:
Inland Fishes of New York

FishBase Summary

Author: Pam Fuller, and Matt Neilson

Revision Date: 6/28/2011

Peer Review Date: 6/28/2011

Citation Information:
Pam Fuller, and Matt Neilson, 2024, Ichthyomyzon unicuspis Hubbs and Trautman, 1937: U.S. Geological Survey, Nonindigenous Aquatic Species Database, Gainesville, FL, https://nas.er.usgs.gov/queries/FactSheet.aspx?speciesID=834, Revision Date: 6/28/2011, Peer Review Date: 6/28/2011, Access Date: 6/19/2024

This information is preliminary or provisional and is subject to revision. It is being provided to meet the need for timely best science. The information has not received final approval by the U.S. Geological Survey (USGS) and is provided on the condition that neither the USGS nor the U.S. Government shall be held liable for any damages resulting from the authorized or unauthorized use of the information.


The data represented on this site vary in accuracy, scale, completeness, extent of coverage and origin. It is the user's responsibility to use these data consistent with their intended purpose and within stated limitations. We highly recommend reviewing metadata files prior to interpreting these data.

Citation information: U.S. Geological Survey. [2024]. Nonindigenous Aquatic Species Database. Gainesville, Florida. Accessed [6/19/2024].

Contact us if you are using data from this site for a publication to make sure the data are being used appropriately and for potential co-authorship if warranted.

For general information and questions about the database, contact Wesley Daniel. For problems and technical issues, contact Matthew Neilson.