News Release From The Nature Conservancy
Michigan Chapter: 101 East Grand River · Lansing, MI 48906-4348 - Website: nature.org/michigan · Email: firstname.lastname@example.org
FOR IMMEDIATE RELEASE -- May 30, 2003
Contact: Melissa Soule, Communications Director; (517) 316-2268 or email@example.com
Michigan's Most Unwanted: Lake & Stream Invaders
LANSING, Mich. — In honor of Aquatic Nuisance Species Awareness Week, May 31-June 7, The Nature Conservancy is joining forces with Gov. Granholm and the Office of the Great Lakes to combat the 160 aquatic nuisance species that cost millions of dollars to businesses, taxpayers, public and private landowners for removal and restoration.
An aquatic nuisance species (ANS) is defined as a waterborne, non-native and invasive organism that threatens the diversity or abundance of native species, the ecological stability of impacted waters, or threatens a commercial, agricultural, aquacultural or recreational activity. From a conservation standpoint, the spread of invasive species—including aquatic nuisance species—is the second largest and fastest growing threat to biodiversity. In fact, invasive species threaten almost 50% of endangered or imperiled species in the United States.
"Once introduced, aquatic nuisance species can forever alter our lakes and streams. In the worst cases, infested waterbodies are like a house that is hopelessly infested with roaches," said Nature Conservancy Aquatic Ecologist Paul Marangelo. "Species like zebra mussels and round gobies have had drastic impacts, which underscores the need to prevent other potential invaders from being introduced."
Marangelo said that to a state like Michigan, the threat is even more prevalent and pervasive given that most of our state is surrounded by the Great Lakes and the state is well known for its lakes and rivers. In 1985, zebra mussels were accidentally dispersed into the Great Lakes via the ballast water of a Caspian Sea tanker. This invasive species is a major threat to the nearly 45 native mussel species in Michigan and nationwide has cost waterfront industries between $750 million to $1 billion in damage repairs during the last decade alone.
"More people are learning about the negative effects of zebra mussels, but there is a large number of other potential invaders that can be just as damaging," Marangelo said. "The Asian carp is only one electric barrier away from Lake Michigan at this point. If we can halt the carp now, we can save a tremendous amount of time, energy and money in the future."
The goal of ANS Awareness Week is to educate Michiganders on the severity of
the problem aquatic nuisance species cause on our waterways. By knowing what to
watch out for and learning preventive measures, we can all work to curb the
current outbreak of invasive species and avert future infestations, Marangelo
For more information and to view pictures of these species, visit The Nature Conservancy’s Michigan website at: http://nature.org/michigan and click on the "Spring 2003 Newsletter" link. The site also includes listings and photos of invasive insects and plants affecting Michigan habitats.
The mission of The Nature Conservancy is to preserve the plants, animals and natural communities that represent the diversity of life on Earth by protecting the lands and waters they need to survive. The Nature Conservancy counts at least 1 million members worldwide, including more than 32,000 in Michigan. The Conservancy and its members have protected more than 80 million acres on Earth, including more than 73,000 acres in Michigan. The Nature Conservancy embraces a non-confrontational, market-based approach for accomplishing its science-driven mission.
WHAT YOU CAN DO (Courtesy of the Michigan College Sea Grant Program)
Zebra Mussel/Dreissena polymorpha
BASIC ID A small D-shaped clam, yellowish to brownish shell, with dark and light colored stripes. Usually found in clusters, attached to solid objects via a strong series of thread-like structures. Usually found in water less than 30 feet deep.
HISTORY A native of the Ponto-Caspian region of Eurasia, it has spread to Europe and first appeared in North America in 1988 in the Great Lakes, probably introduced from the ballast discharge of commercial cargo vessels. It has since spread throughout the midwest via the Mississippi and Ohio River waterways, and also to a few east coast states. In Michigan, it has spread from the Great Lakes and is now established in many of our larger inland lakes and rivers. Our most infamous aquatic invader, zebra mussels eliminate native clams from lakes, irrevocably alter aquatic food chains and impact industrial and recreational uses of aquatic systems.
MANAGEMENT Prevention of introduction is the only known strategy to protect waterways. Individual recreational boaters and anglers should take proper precautions to reduce the risk of transporting this mollusk to uninfested waters.
Round Goby/Neogobus melanostomus
BASIC ID A small bottom-dwelling fish (usually less than seven inches) that is mostly restricted to waters of the Great Lakes. Gobies have large heads and soft bodies, and the appearance of adults can vary from having blotches of black and brown to grey to solid black. They also resemble sculpins, which are a native bottom dwelling fish. But unlike sculpins, gobies have a fused pelvic fin on their underside.
HISTORY Round gobies were probably introduced into the Great Lakes via ballast water discharge from commercial cargo vessels. They were first discovered in the St. Clair River in 1990 and have since expanded to all the Great Lakes, St. Lawrence Seaway, and the Mississippi River via the Chicago Sanitary Ship Canal. Gobies can outcompete and displace native bottom-dwelling species such as sculpin and some darters, and have the ability to survive in degraded water conditions.
MANAGEMENT An electric control barrier installed in the Chicago Sanitary Ship canal was too late to prevent gobies from moving into the Mississippi River, but similar barriers can prevent its dispersal into other canal-connected waterways. Control strategies are mostly limited to efforts to keep the goby from spreading, as there are no known environmentally sound control options.
Rusty Crayfish/Orconectes rusticus
BASIC ID Crayfish are very difficult to identify. A general characteristic which can be helpful in identifying rusty crayfish are rust-colored spots which sometimes appear on the sides of the body of rusty crayfish.
HISTORY Native to areas of the central midwest, the rusty crayfish has expanded its range northward mainly via non-resident anglers bringing crayfish north for use as bait. It outcompetes native crayfish, and can have a substantial negative impact on beds of native plants, which are an important fish habitat.
MANAGEMENT Like most other aquatic invasive animals, there is no ecologically sound way to control this species other than preventing its spread.
Spiny Water Flea/Bythotrephes cederstroemi
Fishook Water Flea/Cercopagis pengoi
BASIC ID Small planktonic water fleas, both have a body of about two millimeters in length with a spiny tail of eight to 10mm long. They are difficult to see individually, but are most often detected as masses of animals snagged on nets or fishing line, with an appearance of cotton batting.
HISTORY Both these species were probably introduced to the Great Lakes via ballast water from deballasting cargo vessels. Spiny water fleas are found in all the Great Lakes an a few inland lakes, and have been present since the mid-1980s. Fishook waterfleas are more recent invaders, discovered in Lake Ontario in 1998, and are now found in all Great Lakes. These species impact basic elements of the foodchain of the Great Lakes because both feed on other species of zooplankton and are able to attain extremely high population densities. Impacts may eventually reverberate up the food chain into fish populations.
MANAGEMENT There is not ecologically sound way to control these species once they become established. Anglers and recreational boaters need to take precautions to prevent their inadvertent introduction into inland lakes.
Eurasian Water Milfoil/Myriophyllym spicatum
BASIC ID This species can be difficult to tell apart from other native aquatic plants. Like many other aquatic plants, it has slender stems with feathery leaves. It often forms dense mats of vegetation in shallow water.
HISTORY Eurasian water milfoil reached spread into the Great Lakes from the east in the 1950s via boats and the movement of waterbirds. It is found in most if not nearly all inland lakes in Michigan, and can form dense mats of vegetation that crowds out native species. Its ability to establish itself from plant fragments is one of the reasons why this pest species has become so ubiquitous in inland waters in Michigan.
MANAGEMENT Mechanical harvesting and chemical treatments have long been used to control Eurasian milfoil, but such efforts are costly and can cause adverse ecological side effects. Recently, experimental releases of a native weevil that feeds preferentially on Eurasian milfoil have had some success in curtailing problematic milfoil infestations in some lakes.
Eurasian Ruffe/Gymnochephalus cernus
BASIC ID Ruffe resemble yellow perch in the body and have coloration similar to walleye (which are both relatives of the ruffe), but are smaller than both these species. Adults are typically four to six inches long, and differ from perch and walleye in that they have a large continuous dorsal fin with spots between its rays.
HISTORY Another probable ballast water introduction, ruffe were first detected in western Lake Superior in the mid 1980s and have been spreading slowly to other areas of the Great Lakes. Besides Lake Superior, they are now found in Lake Huron near Alpena and Lake Michigan near Escanaba. Their aggressive and opportunistic nature has enabled them to outcompete native fish species, and they constitute over 80% of the bottom-dwelling fish community in the St. Louis Estuary in Lake Superior. They have also invaded a small number of Lake Superior tributary rivers.
MANAGEMENT There is no known control strategy for this species, other than implementing strategies to prevent its spread. This species can potentially be spread to inland waters via bait buckets.
Curly Leaf Pondweed/Potamogeteon crispus
BASIC ID This invader is distinguished from other aquatic plants by undulating (or "curly") leaf edges.
HISTORY Curly leaf pondweed has been long established in Michigan, predating most of our other well-known invaders. It can be found in the Great Lakes as well as many if not most inland lakes and rivers, and can form dense mats of vegetation, much like Eurasian water milfoil.
MANAGEMENT Chemical control and
mechanical harvesting have been used to control this species, but such measures
are not without related adverse ecological impacts.
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