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Spiny Water Flea

Scientific Name

Bythotrephes longimanus (Leydig, 1860) (ITIS)

Common Name

Spiny water flea


Bythotrephes cederstroemi (Yan et al. 2011)

Native To

Eurasia (Yan et al. 2011)

Date of U.S. Introduction

First discovered in Lake Huron in 1984; established in all of the Great Lakes by 1987 (Cullis 1988)

Means of Introduction

Most likely introduced through ballast water (Yan et al. 2011)


Has caused a decline in the population of zooplankton as a result of predation (Vanderploeg et al. 2002); may also compete with some native species, such as perch and small crustaceans (Branstrator and Lehman 1996)

Spiny water flea

Spiny waterflea, adults


Photo by Gary Montz

Find more images


  • New to New Hampshire - Invasive Spiny Water Flea Confirmed in Lake Winnipesaukee

    • Sep 29, 2023
    • New Hampshire Department of Environmental Services.

    • This summer, state biologists from the New Hampshire Department of Environmental Services (NHDES) documented the presence of a new aquatic invasive species to New Hampshire. The spiny water flea (Bythotrephes longimanus) was documented on September 13 in the deepest location of Lake Winnipesaukee, in the Broads in Gilford, New Hampshire. Subsequent sampling also confirmed spiny water flea presence in Alton and Wolfeboro areas of the lake. State biologists believe this is a recent infestation.

Distribution / Maps / Survey Status


Selected Resources

The section below contains highly relevant resources for this species, organized by source.

Council or Task Force
Federal Government
State and Local Government