Aquatic Nuisance Invasive Species

The Aquatic Nuisance Species Task Force is an intergovernmnetal organization designed to combat the spread of and manage aquatic invasive species in America.

You can reference their website for more information

They have documented the amount of Aquatic Nuisance Species (ANS) in several major watersheds.

* San Francisco Bay/Inland Delta, CA - 234 species (plus up to 123 others).
* Great Lakes - 139 species
* Hudson River, NY 154 species
* Coos Bay, OR - 67+ species
* Florida inland waters - 154+ species
* Chesapeake Bay - 120+ species
* Hawaii - 4,465 species
* U.S. (OTA 1993) - 4,500+
* Proportion causing serious harm 15%

According to their data the rate of introduction of new species has been increasing over time. With each nuisance species tremendous amounts of money are lost as a result of lost productivity, decline of native ecosystems, or management costs.

Transport Methods:

Ballast Water: Large ships are responsible for the dispersal of many non-native species. Ships travel between different ecosystems and can pick up various species in their ballast water, they then release these species in new watersheds when they empty out the water.

Recreational Boating: Recreational boaters can carry organisms on their boat inadvertently. Then the next time the boat is in the water it may introduce the species into a new region. This is a major method by which zebra mussels are being transported westward

Interbasin Transfers: As engineers have created canals and locks, watersheds that were previously independent are now connected. Invasive species are able to enter into new regions that were previously inaccessible. This is of particular concern with Asian carp entering the Great Lakes

Here are some relevant species of concern to the Great Lakes Region:

Zebra Mussel
( Dreissena polymorpha )

Zebra MusselsDESCRIPTION: Zebra mussels are freshwater bivalve mollusks that typically have a dark and white (zebra-like) pattern on their shells, but may be any combination of colors from off-white to dark brown (hence the name "polymorpha"). They are alien to North America but have invaded many of our waters, east of the 100th Meridian from Ontario Canada and the Great Lakes to southern Louisiana. Zebra mussels are usually about an inch or less long, but may be larger. When healthy, they attach to hard substrates, often found in clusters much like marine mussels, but unlike any other freshwater bivalve in North America.

PATHWAYS/HISTORY: Zebra mussels are native to eastern Europe and western Asia, from the Black and Caspian Sea drainages. Until the mid 1980s there were no zebra mussels in North America. Quickly that changed when they were inadvertently introduced into waters near the Great Lakes region. It is suspected that zebra mussels hitched a ride in ballast water tanks of commercial ships. Zebra Mussels were first discovered in the United States in Lake St. Clair near Detroit, Michigan in 1988. Since the '80s, zebra mussels have spread, unchecked by natural predators, throughout much of the eastern United States. They currently infest much of the Great Lakes basin, the St. Lawrence Seaway, and much of the Mississippi River drainage system. The have begun to spread up the Missouri River and Arkansas River.

RISKS/IMPACTS: Zebra mussels reproduce quickly and in large numbers, typically creating large populations. Zebra Mussel densities have been reported to be over 700,000 individuals per square meter in some facilities in the Great Lakes area. Zebra mussels are biofoulers that occlude pipes in municipal and industrial raw-water systems, requiring millions of dollars annually to treat. They produce microscopic larvae that float freely in the water column, and thus can pass by screens installed to exclude them. Monitoring and control of Zebra Mussels costs millions of dollars annually. As filter feeders, zebra mussels remove suspended material from the habitat in which they live. This includes the planktonic algae that is the primary base of the food web. Thus, zebra mussels may completely alter the ecology of water bodies in which they invade.

MANAGEMENT: Once zebra mussels have established in a water body, there is no known method of eradication. Preventing spread remains our best course of action. Since zebra mussels have planktonic (free drifting) larvae, preventing spread to water bodies downstream from known infestations may not be possible. However, westward, overland spread is assumed to be largely due to trailered boat traffic. Thus, further westward spread of zebra mussels is highly preventable.

WHAT YOU CAN DO: As a general practice, wash and scrub your boat and equipment, allowing it to completely dry, before moving to a new water body. Tiny mussels attached to your boat may not be visible to the naked eye. High pressure water at a temperature above 104 ºF will kill zebra mussels and is the best choice for washing your boat and equipment in order to prevent spread. Be sure to drain all water from your boat, including bilges, live wells, bait buckets and coolers. Never transport water or plants from one water body to another.

Rusty Crayfish
( Orconectes rusticus )

New Zealand MudsnailDESCRIPTION: Rusty crayfish live in lakes, ponds and streams, preferring areas with rocks, logs and other debris in water bodies with clay, silt, sand or rocky bottoms. They typically inhabit permanent pools and fast moving streams of fresh, nutrient-rich water. Adults reach a maximum length of 4 inches. Males are larger than females upon maturity and both sexes have larger, heartier, claws than most native crayfish. Dark “rusty” spots are usually apparent on either side of the carapace, but are not always present in all populations. Claws are generally smooth, with grayish-green to reddish-brown coloration. Adults are opportunistic feeders, feeding upon aquatic plants, benthic invertebrates, detritus, juvenile fish and fish eggs.

PATHWAYS/HISTORY: The native range of the rusty crayfish includes Ohio, Tennessee, Kentucky, Indiana, Illinois and the entire Ohio river basin. However, this species may now be found in Michigan, Massachusetts, Missouri, Iowa, Minnesota, New York, New Jersey, Pennsylvania, Wisconsin, New Mexico and the entire New England state area (except Rhoda Island). The Rusty crayfish has been a reported invader since at least the 1930’s. Its further spread is of great concern since the prior areas of invasion have led to severe impacts on native flora and fauna. It is thought to have spread by means of released game fish bait and/or from aquarium release. Rusty crayfish are also raised for commercial and biological harvest.

RISKS/IMPACTS: Rusty crayfish reduce the amount and types of aquatic plants, invertebrate populations, and some fish populations—especially bluegill, smallmouth and largemouth bass, lake trout and walleye. They deprive native fish of their prey and cover and out-compete native crayfish. Rusty crayfish will also attack the feet of swimmers. On the positive side, rusty crayfish can be a food source for larger game fish and are commercially harvested for human consumption.

MANAGEMENT: Rusty crayfish may be controlled by restoring predators like bass and sunfish populations. Preventing further introduction is important and may be accomplished by educating anglers, trappers, bait dealers and science teachers of their hazards. Use of chemical pesticides is an option, but does not target this species and will kill other aquatic organisms.

WHAT YOU CAN DO: Do not use rusty crayfish as bait in areas where it is not native. Never transport bait from one water body to another. Discard your bait in the trash before leaving. Never release pet crayfish (or any other organisms) into the wild.

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