Spiny waterflea

Scientific Name: Bythotrephes longimanus

J. Liebig, NOAA GLERL, 2001Copyright Info

Identification: The spiny waterflea (sometimes written as "water flea") is a freshwater crustacean with a straight tail spine that is twice as long as its body. The tail spine has one to three pairs of hooks. This species is a large-sized type of zooplankton, which are small animals that live suspended in the water.

Size: The spiny waterflea can reach up to 0.5 inch (15 mm) in length.

Native Range: This species is native to northern Europe and Asia.

Table 1. Great Lakes region nonindigenous occurrences, the earliest and latest observations in each state/province, 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 Bythotrephes longimanus are found here.

Full list of USGS occurrences

State/ProvinceYear of earliest observationYear of last observationTotal HUCs with observations†HUCs with observations†
Illinois198620112Lake Michigan; Little Calumet-Galien
Indiana198619881Lake Michigan
Michigan1984201711Betsie-Platte; Betsy-Chocolay; Dead-Kelsey; Keweenaw Peninsula; Lake Huron; Lake Michigan; Lake Superior; Michigamme; Ontonagon; Pere Marquette-White; Thunder Bay
Minnesota198720164Baptism-Brule; Cloquet; Lake Superior; St. Louis
New York198520195Lake Champlain; Lake Erie; Lake Ontario; Mettawee River; Oneida
Ohio198520191Lake Erie
Pennsylvania199820021Lake Erie
Vermont201420141Lake Champlain
Wisconsin198620176Bad-Montreal; Door-Kewaunee; Lake Michigan; Lake Superior; Lower Fox; Menominee

Table last updated 10/11/2019

† Populations may not be currently present.

* HUCs are not listed for areas where the observation(s) cannot be approximated to a HUC (e.g. state centroids or Canadian provinces).

Means of Introduction: The spiny waterflea was probably introduced into the Great Lakes by transoceanic ships discharging water or mud.

Status: The spiny waterflea is in all of the Great Lakes and many inland lakes in the region.

Remarks: The spiny waterflea is most abundant in the late summer and autumn. Population density is mostly determined by water temperature and salinity.

Author: Illinois-Indiana Sea Grant

Contributing Agencies:
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Revision Date: 8/28/2012

Citation for this information:
Illinois-Indiana Sea Grant, 2019, Spiny waterflea: U.S. Geological Survey, Nonindigenous Aquatic Species Database, Gainesville, FL, and NOAA Great Lakes Aquatic Nonindigenous Species Information System, Ann Arbor, MI, https://nas.er.usgs.gov/queries/greatLakes/FactSheet.aspx?SpeciesID=162&Potential=N&Type=1&HUCNumber=, Revision Date: 8/28/2012, Access Date: 10/17/2019

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.