Spiny Waterflea 
Bythotrephes longimanus
Image by Kate Feil

Spiny Water Flea

Spiny Waterflea Map
Image by USGS

Map by USGS on HUC level record of spiny water flea in the United States

Spiny Water Flea

First detected in Lake Huron in 1984, the spiny water flea quickly spread throughout all of the Great Lakes and many inland lakes. Recently, it has been confirmed in Lake George. The spiny water flea was likely introduced from ballast water; however, its current spread is due to recreational boating, ballast water transfer, and water currents.

The spiny water flea is planktivorous and has caused major changes in zooplankton community structure. A major prey of the spiny water flea is Daphnia, a native water flea, and has shown severe population declines coincident with the introduction of the spiny water flea. In addition, density of a native predatory zooplanktor, Leptodora, has declined with the invasion of the spiny water flea. Decline ofLeptodora may be due to the spiny water flea outcompeting it for Daphnia. The spiny water flea may alter the Great Lakes food web by reducing the abundance of prey for young-plankton eating fish.


Spiny Water Flea – Fact Sheet from the US Geological Survey Nonindigenous Aquatic Species website covers identification, nonindigenous occurrences, ecology, impact, and management of the species. 

Spiny Water Flea Effects - an article on "The spread, establishment and impacts of the spiny waterflea, Bythotrephes longimanus, in temperate North America: a synopsis of the special issue"

Spiny Water Flea Species Profile on the USDA National Invasive Species Information Center website provides a brief profile on the species.

What Are Spiny Water Fleas? on the Protect Your Waters website provides basic information on spiny water fleas.

Last updated June 25, 2019