Spiny water flea (Bythotrephes longimanus) Spiny Water Fleas are zooplankton (microscopic animals).Spiny Water Fleas are like a glob of jelly with back spots; the adults can grow to 3/8 inches long. These have one large eye that is black and red; their tails are 70% of the body size. They can be found in deep lakes but can be found in shallow lakes and rivers. Spiny water fleas eat small animals (zooplankton), including Daphnia, which are an important food for native fishes. In some lakes, they caused the decline or elimination of some species of native zooplankton. They can clog eyelets of fishing rods and prevent fish from being landed. During the warm summer condition each female can produce up to 10 offspring every two weeks. As temperature drop in the fall, eggs are produced; they can lie dormant all winter. As water temperature warms in the spring, individuals hatch from “resting” eggs that have overwintered on the lake bottom. Throughout much of summer, spring, and autumn, the population is composed mostly of females. These females eggs that remain unfertilized and are carried in the mothers brood pouch until the develop into female offspring that are genetically identical to the mother. This cycle of asexual reproduction, requiring no fertilization, continues as long as the water temperature is neither too hot nor too cold and food is abundant. Spiny water flea impacts to lake ecosystems are largely unknown. The water fleas compete with small fish for food called zooplankton while larger fish eat them tiny fish may not be able to consume this invades. In certain types of lakes, they can change the species and numbers of zooplankton which may harm those lake ecosystems. They were first discovered in Lake Ontario in 1982 and spread to Lake Superior in 1987 and last seen in Lake Huron in
