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Mississippi River Invasive Exotic Species - WDNR

Aquatic invasive species have been introduced into the Mississippi River watershed in a number of different ways. Some were introduced deliberately such as carp, whereas others were released accidentally elsewhere and invaded the Mississippi River through watershed connections.

The Great Lakes- Illinois River Connection

The Chicago Sanitary and Ship Canal which connects the Great Lakes to the Mississippi River watershed is one of the main avenues of access to the Mississippi River for aquatic invasive species.
map of Chicago Sanitary and Ship Canal The Chicago Sanitary and Ship Canal, has allowed invasive species such as zebra mussels, to move between basins.Map from Wikipedia (USGS) This connection, the Chicago Sanitary and Ship Canal, has allowed invasive species which have been introduced to the Great Lakes, such as zebra mussels, to move between basins. An electric barrier was activated in April 2002 to prevent fish from moving from one basin to the other. More fromWikipedia

Historically the two watersheds were separate. More than a century ago channels were built to move freight and people between the Illinois River and Lake Michigan.Ultimately the direction of the rivers connected to these canals was changed to carry sewage away from Lake Michigan, which was Chicago’s drinking water source.

What you can do to prevent their spread!

Once the invaders are in our waters everyone who boats or fishes has the potential to move them to a new water body. The good news is that there are step that we can take to help prevent their spread.

Inspect and remove aquatic plants from your boat and equipment
Drain water from you boat and equipment before leaving the boat landing
Dispose of unwanted live bait in the trash or share it with a fellow angler
Rinse your boat and equipment with high pressure or hot water. OR
Dry your boat and equipment thoroughly for at least five days.

Natural resource managers are actively monitoring the Mississippi River to better understand where these species are found and what effect they are having. Citizens are also encouraged to aid in monitoring efforts. Learn what these invasive species look like. If you think you have discovered a new infestation of an invasive plant or animal report it to the DNR immediately. In some cases management decisions are made to protect native populations.

More about Infamous Exotics on the Upper Mississippi River

Invasive exotic animal species threaten the diversity of the Mississippi River System by competing with native species for food and habitat. Invasive plants can take over important floodplain habitat such as shorelines, marshes and bottomland forests and clog waterways.

Zebra Mussels

These hardy and prolific mollusks can firmly attach themselves to solid objects. The mussels are usually found growing in clusters containing numerous individuals which clog water intakes, encrust piers and docks. They also encrust native mussels ultimately smothering them, which has caused significant declines in native mussels on the Mississippi River. These tiny filter feeders (1/8-inch to 2-inch)strain the same plankton from the water that young native game fish and native mussels depend on for food.

Native to Eastern Europe, they were brought to North America as larvae in ballast water of ships that traveled from fresh-water Eurasian ports to the Great Lakes. They were found in all of the Great Lakes by 1990 and by 1991, the mussels had made their way into Pool 8 of the Mississippi River via the Illinois River. Currents carried the larvae downstream to the confluence with the Mississippi, from which barges could carry them upriver. Populations of zebra mussels are steadily increasing to over several thousand per square meter in some portions of the Mississippi River. As of 2005, their distribution included the entire Wisconsin portion of the Mississippi and extended up to Stillwater in the St Croix River. They have also spread to more than 40 inland waters in Wisconsin.

Round Gobies

These fish are bottom dwelling with a large head, frog like raised eyes thick lips and black dorsal spot, which can grow to be 10-12 inches long. Like zebra mussels they are native to Eastern Europe. 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 Erie, Michigan and Superior and to the Illinois River. Round gobies are thriving in the Great Lakes Basin because they are aggressive, voracious feeders which can forage in total darkness. They compete directly with native fish for food and habitat,in addition to preying upon their eggs and young. They also take over prime spawning habitats and spawn several times per year, whereas native fish only spawn once a year, making them tough competition for native fish. As of 2005, round goby were considered to infest the Chicago Sanitary and Ship Canal, as well as the lower reaches of the Des Plaines River.

Rusty Crayfish

Rusty crayfish are native to the Ohio River drainage and were most likely spread to Wisconsin waters by anglers who dumped their bait buckets. They eat fish eggs and feed on aquatic vegetation, which deprives native fish of food and cover. They also displace native crayfish by forcing the native crayfish from the best daytime hiding places making them more vulnerable to fish predation. Secondly, native crayfish generally try to swim away from a fish attack, whereas rusty crayfish assume a claws up stance in the face of a predator which reduces their own susceptibility to predation. Rusty crayfish are found in at least 300 inland lakes and rivers in Wisconsin, including the Mississippi and St. Croix Rivers and their tributaries.

Asian carp (bighead, silver and grass carp)

bighead carp These carp were first brought to the United States from China in the 1970’s by Arkansas fish farmers to improve water quality by removing algae from fish production ponds. They escaped from the fish farms, probably during floods and began to appear in the southern Mississippi River in the 1980’s. They have been moving north at a rate of about 50 miles per year and are now present in large numbers below Lock and Dam 19 in Iowa.

Bighead and silver carp are filter feeders, straining tiny animals and plants (plankton) out of the water.Some may eat their weight in plankton daily. In eating plankton, these fish directly compete with native filter feeders such as mussels and fish. This competition for food can potentially disrupt the entire food web in a water body. There is great concern about their potential to affect Great Lakes, Mississippi River, and St. Croix River fish communities should they become established in Wisconsin waters. Both fish species are known to jumpout of the water in response to boat motors!

Grass carp were first introduced into southern states in the 1960’s to control aquatic vegetation in fish farms. They spread through accidental and illegal, intentional releases. Grass carp have the potential to seriously disrupt the food web, as they can consume considerable amounts of aquatic vegetation that other organisms rely on for food and cover.

Status:Lock and Dam 19 has not proven to be an insurmountable barrier to them as a bighead and silver carp were Pool 4 (Lake Pepin) in the fall of 2003 and five Asian carp including a silver, two grass and a bighead carp were caught by a commercial fisherman in Mississippi River near La Crosse, November 2008. The fish were discovered at a market in Pepin and reported to the Minnesota DNR.

Both species are present in the Illinois River and at the end of 2005, Asian carp appeared to range as far as about 20 miles downstream of the electrical fish barrier or about 50 miles from Lake Michigan.

Controlling Asian Carp:

Great Lakes

The only thing that is keeping these fish from moving into Lake Michigan is an electrical barrier system on the Chicago Sanitary and Ship Canal, though this is not a fail-safe system. Although the barrier acts to repel the fish, it doesn’t actually kill them. The construction of similar barriers at two points along the Mississippi has been recommended, though this system will need to be more technologically advanced and thus will be more expensive. This is because the design must allow the free flow of native fish up and downstream for spawning while simultaneously blocking movement of the Asian carp upstream.

Upper Mississippi River

University of Minnesota researchers are evaluating the possible release of sterile or genetically modified fish, as well as the use of pheromones or other sensory cues, to reduce the numbers of Asian carp in the wild. Early detection of isolated populations may help slow or restrict the spread of these Asian carp. To report a sighting, note exact location. Freeze specimen in a sealed plastic bag and call your local DNR Service Center

Faucet snails and Exotic Parasitic Trematodes

The faucet snail is a European species that has spread into Wisconsin waters including the Mississippi River. This small snail can serve as an intermediate host for exotic trematodes or flukes, which are intestinal parasites for waterbirds. Tremetode caused waterbird mortality was first confirmed on Pool 7 of the Mississippi River near La Crosse, Wisconsin during the 2002 spring migration. Die offs of coots and lesser scaup now occur each spring and fall on Pool 7 and 8. The die-offs of coots and lesser scaup from trematodes closely parallel other locations within Wisconsin where faucet snails have been found.

These species of tremetodes have not been reported to infect humans. Futher,no human health threats have been documented form handling or consuming waterfowl infected with tremetodes.

Eurasian water milfoil

is an aquatic plant native to Europe and Asia. Its stem fragments cling to boats, motors,and trailers and drift with currents to colonize new areas. These fragments can root and grow into new plants, allowing it to spread over long distances. Eurasian water milfoil may form dense stands, crowding out native vegetation and creating mats so dense that game fish can’t maneuver through them to snap up their prey. Eurasian water-milfoil is found in portions of the Mississippi River, the St. Croix River south of St. Croix Falls,and in more than 380 inland lakes in Wisconsin.

Curly-leaf pondweed

is another invasive plant that is carried to new water bodies on boats and trailers. Native to Europe and Asia, it was thought to have been accidentally introduced along with the common carp. This plant, with its characteristic wavy leaves, grows rapidly early in the spring (even under ice), and shades out native plants. Like Eurasian water milfoil, it can form dense mats that make it tough to boat or swim. When curly-leaf pondweed dies back in mid-summer it releases nutrients, which can lead to algal blooms and other problems. It is found in portions of the Mississippi and upper St. Croix rivers and their tributaries, as well as an unknown number of inland lakes.

Currently neither Eurasian water milfoil nor curly pondweed has been much of a problem in the Mississippi River. They are both present as a part of the vegetation community, but are not dominant. Both can attain very high biomass in limited portions of the river but they seldom maintain that biomass over more than one season.

Purple loosestrife

This plant was introduced as a garden perennial from Europe during the 1800's. It is still promoted by some horticulturists for its beauty as a landscape plant, and by beekeepers for its nectar-producing capability. Currently, about 24 states have laws prohibiting its importation or distribution because of its aggressively invasive characteristics. Purple loosestrife was first detected in Wisconsin in the early 1930's, but remained uncommon until the 1970's. It is now widely dispersed in the state, and has been recorded in 70 of Wisconsin's 72 counties. This plant invades wetlands,lake and river shorelines, and moist roadsides where it displaces native vegetation and reduces available habitat and food for wildlife. It spreads by seeds and by broken stems that root in moist soil. Purple loosestrife occupies many shorelines and backwaters along the Mississippi, and is still relatively uncommon on the St. Croix, though locally abundant at some lower river sites. It is found in some tributaries of both rivers and in lakes in those systems.;

Common Buckthorn

This tree is small, exotic, and very invasive reaching 20-25 feet in height and 10 inches in diameter. Most often they grow in a large shrub growth form, having a few to several stems from the base. Buckthorn is easily spread by birds. It bears small black berries in late summer, which readily attract birds such as waxwings and robins. The seeds then pass through their digestive system.After the first tree produces fruit, buckthorn can spread rapidly just from fruit which drops to the ground. Once established buckthorn forms a dense thicket which can shade out other plants and shrubs in the under story and may prevent the establishment of other tree seedlings. Unfortunately it has little wildlife value other than the berries. Despite the fact that its leaves stay green well into winter deer tend to use it only as starvation food.

Buckthorn is widespread in western Wisconsin and can occur anywhere there is disturbance in the woods. There are well-established pockets of it in many natural area sites including Hixon Forest, by La Crosse, WI and Kinnickinnic State Park near Hudson, WI, and Rush Creek State Natural Area near Ferryville,WIas well as many locations on private land. Buckthorn is also becoming increasingly present in the bottomland forest along the Mississippi River.

Links

Freshwater Mussels of the Upper Mississippi River -U.S Fish and Wildlife Service (USFWS) [exit DNR]
<>Nonindigenous Aquatic Species, United States Geological Survey (USGS) [exit DNR]
Asian Carp and the Great Lakes , Environmental Protection Agency (EPA)

Mississippi Interstate Cooperative Resource Association
Invasive Species Program ;-U.S. Fish and Wildlife Service (USFWS)

Invasive Species - Wisconsin DNR

State of Wisconsin AIS Comprehensive Management Plan, Sept. 2003

State of Wisconsin AIS Website