Origin

Northern Europe and Asia.

Habitat

Spiny waterflea prefer cold, and open (generally pelagic) waters, but can persist in a wide range of lentic (still-water) conditions.

LifeCycle

Spiny waterflea populations tend to peak between early September and early November. When food (other zooplankton) is readily available and temperatures are warm, males will feed while females reproduce through parthenogenesis, not requiring fertilization from their male counterparts. During this time, only females are produced (sex of offspring is determined by water temperature and prey availability). As water cools and food declines, more males will be produced. Females can produce between 1-24 embryos which can be found in their brood pouch—if successful, these embryos can be dropped into sediment as resting eggs where they often survive the winter. Eggs will hatch in spring/early summer.

Ecological Threat

Lake monitoring has shown the spiny waterflea, as a result of predatory behavior, to reduce species richness and population sizes within zooplankton communities. This has large implications for Lake Champlain (and other Vermont water bodies acting as fisheries) as it could significantly alter aquatic food web dynamics through direct competition with small fish for zooplankton. Reduction in water clarity is a notable effect of spiny waterflea, one with serious monetary implications. This reduction is water clarity is attributed to spiny waterflea due to the fact that it so voraciously predates on other algae grazers.