Spiny Waterflea

Spiny Waterflea


  • Eat other zooplankton which is an important source of food for fish.
  • Have depleted some sources of native zooplankton in some lakes.
  • May clog eyelets of fishing rods and impede the landing of fish.

Description & Origin

  • Adult spiny waterflea range from 1/4” to 5/8” in length and have a single, straight tail spine twice as long as its body with one to three pairs of barbs.
  • Spiny waterflea are native to Europe and Asia and were introduced into the Great Lakes in the ballast water of ships. They were first discovered in Lake Huron (1984) and Lake Ontario (1985), and spread to Lake Superior by 1987.

Prevent their spread

Spiny waterflea can spread by attaching to fishing equipment, including fishing lines and downriggers, anchor rope, and landing nets. Adult spiny waterflea will accumulate as a visible gelatinous glob on fishing lines and other equipment. While adult spiny waterflea will die out of water, under certain conditions the eggs can resist drying and freezing, and thereby establish a new infestation. They also can be unintentionally transported in bilge water, bait buckets, or livewells. Be sure to Clean, Drain, Dispose, and Dry!