Aquatic Invasive Species
Species

Governor Doyle, as Chair of the Governors Council of Great Lakes Governors, in his letter to the US Departments of Defense and Homeland Security urging full operation of a new barrier system wrote. The Great Lakes are at risk from the grave threat posed by Asian carp and other harmful aquatic invasive species. Without more

The Chinese mystery snails and the banded mystery snails are non-native snails that have been found in a number of Wisconsin lakes. There is not a lot yet known about these species, however, it appears that they have a negative effect on native snail populations. The mystery snail's large size and hard operculum (a trap door cover which protects the soft flesh inside), and their thick hard shell make them less edible by predators such as rusty crayfish.

The Chinese mystery snails and the banded mystery snails are non-native snails that have been found in a number of Wisconsin lakes. There is not a lot yet known about these species, however, it appears that they have a negative effect on native snail populations. The mystery snail's large size and hard operculum (a trap door cover which protects the soft flesh inside), and their thick hard shell make them less edible by predators such as rusty crayfish.

Curly-leaf pondweed is an invasive aquatic perennial that is native to Eurasia, Africa, and Australia. It was accidentally introduced to United States waters in the mid-1880s by hobbyists who used it as an aquarium plant. The leaves are reddish-green, oblong, and about 3 inches long, with distinct wavy edges that are f more

Eurasian water-milfoil is a submersed aquatic plant native to Europe, Asia, and northern Africa. It is the only non-native milfoil in Wisconsin. Like the native milfoils, the Eurasian variety has slender stems whorled by submersed feathery leaves and tiny flowers produced above the water surface. The flowers are locate more

Flowering rush is a perennial aquatic herb that emerges each spring from winter-hardy rhizomes. Emergent leaves are stiff, narrow, sedge-like (3-edged or triangular in cross-section) and up to 3 feet above the water surface. In deep water, the plant can be entirely submerged. Submerged plants have limp leaves and do no more

The freshwater jellyfish found in Wisconsin are one of several species of Craspedacusta native to China. Two species (C. sowerbii and C. sinensis) live in the Yangtze River?the world?s third longest river and one so vast it makes the Wisconsin River seem like a trout stream! Freshwater jellyfish were first reported in North America as early as 1884. Sightings in Wisconsin date back to 1969. Much more remains to be learned about these fascinating creatures. Although they probably evolved from estuarine species, themselves descendents of ocean jellyfish, little is known about the evolution of freshwater jellyfish. That?s because jellyfish leave no fossil records.

Giant hogweed -- a member of the parsley family -- is striking due to its huge size. In the first year of growth, plants form a bush-like rosette of compound leaves (1 to 5 feet wide) that are deeply incised and pointed. Plants flower in their second year (or later, depending on maturity). Flowering plants are 8 to 15 more

EWM has been known to hybridize with northern water-milfoil. The hybrids cannot be distinguished by visual characteristics, but rather have to be identified through DNA analysis.

Japanese knotweed, in the buckwheat family, is a perennial that grows to heights of 5-10 feet in large clones up to several acres in size. The arching stems are hollow and bamboo-like, a reddish-brown to tan color; they die, but remain upright through the winter. Mature leaves are 3-5? wide and 4-9? long, lighter on th more

Purple loosestrife is a perennial herb 3-7 feet tall with a dense bushy growth of 1-50 stems. The stems, which range from green to purple, die back each year. Showy flowers vary from purple to magenta, possess 5-6 petals aggregated into numerous long spikes, and bloom from July to September. Leaves are opposite, nearly more

Quagga mussels (Dreissena bugensis) are closely related to another invader, the zebra mussel (Dresssena polymorpha). Quagga mussels are native to Caspian Sea drainage in Eurasia. They most likely arrived as stowaways in the ballast water of ocean going ships. more

Rainbow smelt is a very small (7 to 9 inches long, weighing 3 ounces) invasive fish. They are silvery overall with a pale green back and iridescent purple, blue and pink on their sides. They have a conspicuous silvery streak running lengthwise along each side. In the water, rainbow smelt shimmer colorfully. When remove more

Red swamp crayfish are dark red in color with raised bright red spots covering the body and claws and a black wedge-shaped stripe on the top of the abdomen. They may vary in length between 2 to 5 inches. Occasionally, a genetic mutation may turn the body and/or claws blue. more

The round goby, Neogobius melanostomus, is a bottom dwelling fish with a large head, resembling a tadpole, which can grow to be 250 mm (10 inches). First discovered in Lake St. Clair in 1990, presumably introduced via ballast water from transoceanic vessels, the round goby and the tubenose goby have spread to lakes Eri more

Rusty crayfish (Orconectes rusticus) are native to streams in the Ohio River Basin states of Ohio, Kentucky, Illinois, Indiana, and Tennessee. They were likely introduced to Wisconsin waters primarily by anglers who used them as live bait. They are still sold as bait and by biological supply companies. It is illegal to more

Sea lampreys (Petromyzon marinus) are primitive, jawless fish native to the coastal regions of the Atlantic Ocean. Unlike other fish that are found in and around Wisconsin, they possess no scales, paired fins, swim bladders, or bones. more

Both waterfleas entered the Great Lakes in ship ballast water from Europe - the spiny waterflea arrived in the 1980's, followed in the 1990's by the fishhook water flea. Only about 1/4 to 1/2 inches in length, individual waterfleas may go unnoticed. However, both species tend to gather in masses on fishing lines and do more

VHS was first detected in Wisconsin in May 2007 in the Lake Winnebago and Lake Michigan systems. Because Lake Superior and the Mississippi River are both connected to Lake Michigan, we suspect that VHS is present in those waters, though it has yet to be confirmed. more

Yellow Floating Heart is an herbaceous, perennial, aquatic plant that has long, branching stems up to 0.1 inch thick. It often covers the water surface with long-stalked heart-shaped leaves. Its leaves are typically opposite and unequal, shaped like a rounded heart, and measure 2-6 inches in diameter. It has bright yel more

The zebra mussel (Dreissena polymorpha) is a tiny (1/8-inch to 2-inch) bottom-dwelling clam native to Europe and Asia. Zebra mussels were introduced into the Great Lakes in 1985 or 1986, and have been spreading throughout them since that time. They were most likely brought to North America as larvae in ballast water of more