Invasive Aquatic Species of the United States

Green crabs, zebra mussels, hydrilla, and Northern Snakehead—what do these organisms all have in common? Each of these species is cropping up in and around waterways outside of their native habitat, and their presence has the ability to disrupt and negatively impact the ecosystems where they make their new homes. Nonindigenous aquatic species, also referred to as invasive, exotic, or non-native, are aquatic organisms that have been introduced to areas outside of their native habitat, whether that introduction is on the other side of the world, or on the other side of a continent. As these plants and animals haven’t evolved with the rest of the life forms in their new neighborhoods, they may not have natural predators in their new zip code—this lends the nonindigenous species an upper hand in competing for resources in the area. Without the typical checks and balances that would exist in their native ecosystems, these plants and animals may end up permanently altering the balance of life in their new home, and can cause additional damage to the human economies and industries that rely on these aquatic ecosystems. Nonindigenous aquatic species are present across the country, in both fresh and salt water, and state and local governments need your help to track and deter their spread. It’s possible that you may have even accidentally helped transfer some of these plants and animals from one water body to another without realizing it—can you recognize these exotic species hiding in plain sight?

Click on the links below to learn more about these invasive species in your state. 

Alabama

Alaska

Arizona

Arkansas

California

Colorado

Connecticut

Delaware

Florida

Georgia

Hawai’i

Idaho

Illinois

Indiana

Iowa

Kansas

Kentucky

Louisiana

Maine

Maryland

Massachusetts

Michigan

Minnesota

Mississippi

Missouri

Montana

Nebraska

Nevada

New Hampshire

New Jersey

New Mexico

New York

North Carolina

North Dakota

Ohio

Oklahoma

Oregon

Pennsylvania

Rhode Island

South Carolina

South Dakota

Tennessee

Texas

Utah

Vermont

Virginia

Washington

West Virginia

Wisconsin

Wyoming

 

 

Alabama

Alabama’s waterways make it home not only to fresh and saltwater fishing, and a variety of other recreational activities, but also to invasive aquatic species that put the health of lakes, rivers, and coastal waters at risk. These invasive species can turn a beautiful fishing hole into a weed-infested swamp or a healthy fishery into an ecological desert, impacting recreational enjoyment and economic stability in the region. Water hyacinth (Eichhornia crassipes) is the most threatening nonnative plant to Alabama’s waters because of their prolific reproductive nature. Water hyacinth propagates so fast that one plant is able to cover 40 acres of water in one growing season. Touted as a pleasant ornamental, the species was brought to the United States from South America in 1884 and has since spread to other subtropical climates throughout North America. Water hyacinths may be attractive, but don’t let the pretty purple flowers fool you! These invaders cover the surface of the water which reduces light and oxygen availability for submerged plants. The plants that are being choked out by water hyacinth are vitally important to the ecosystem because they create habitat for fish and are the primary producers of the food web. When there are no longer any other healthy plants in an aquatic environment, other than the invasive plant, the abundance and variety of life is greatly reduced. Water hyacinth are also known to block water flow, hampering agriculture, fisheries, recreation, and hydropower. If you want to help prevent this invasive species from strangling out precious native organisms and spreading its seeds to other bodies of water, then make sure you clean off any equipment you use where there is water hyacinth before you take it anywhere else, and inform your friends to do the same. Check out this link for more information on the water hyacinth and other invasive species threatening Alabama’s fishing industries and waterways.

 

 

Alaska

When a non-native organism is introduced to a new environment and does not have the typical population checks and balances (i.e. predators and disease), this organism can throw off the biological balance of its new habitat, impacting not only the natural environment around it, but also economic prosperity and human health. Because fishing is among the most important industries in Alaska, a thriving economy is closely tied to a healthy aquatic ecosystem. The Atlantic salmon (Salmo salar) is an example of an invasive species that is threatening Alaska’s native Pacific salmon and trout populations, thus threatening the local fisheries and potentially the economic stability of the industry that depends on these Pacific natives. Native to the North Atlantic Ocean, these salmon are finding their way to Alaska by escaping fish farms off the coasts of British Columbia and Washington and swimming up to the Gulf of Alaska. Farm fish treated for pathogens may not show signs of illness, yet could still be carriers of unfamiliar diseases to the native Alaskan fish. Alaska Department of Fish and Game (ADF&G) believes that because of the potential for disease dissemination and Atlantic salmon’s inherently more aggressive nature than Pacific salmon and trout, it would not be difficult for them to overwhelm native populations and put Alaska’s aquatic biodiversity at risk. ADF&G suggests that if you come across an invasive salmon to keep it whole, note the location it was caught (GPS coordinates if possible), and contact your local office of ADF&G to report an invasive fish. Check out this link for more information on the Atlantic salmon and other invasive species threatening “The Last Frontier.”

 

 

Arizona

In Arizona it’s enough to make a person cry when the lake they intended to go swimming in looks like it may be polluted. While anyone familiar with Arizona’s dry climate knows how important a place to swim during the summer months is, a healthy lake affects more than just recreational endeavors. Infrastructure and the economy, biodiversity and entire ecological systems; these are the potential victims of invasive species. Quagga mussels (Dreissena polymorpha) are an example of a species that puts the well-being of the local aquatic systems and all that relies on them at risk. These organisms made their way to North America from eastern Europe and Ukraine in the 1980s when ships with mussels attached to them docked in the Great Lakes. Since then, these tiny trespassers have migrated inland to states including Arizona, Colorado, and Utah. They were first found in Arizona in Lake Mead in 2007. They can produce 40,000 eggs per breeding cycle with multiple cycles every year and they are incredibly tolerant of a wide range of habitats, so wherever these mussels become established, they have a dramatic impact. Quagga mussels consume large amounts of phytoplankton, which removes valuable nutrients from the water column before other organisms can benefit from them, they clog pipes and water conveyance infrastructure, and they damage motors on boats and any infrastructure that comes in contact with water (i.e. docks, bridges, and navigational equipment). According to Arizona Game and Fish Department, “whether you fish, or boat, or simply get water and electricity to your home, these aquatic invaders will affect your lifestyle… and possibly your wallet.” If you want to help contain these prolific invaders, follow the “clean, drain, and dry” method of making sure you don’t carry any mussels from one body of water to another. Check out this link for more information on invasive species in Arizona.

 

 

Arkansas

Nicknamed “The Natural State,” Arkansas boasts world-class, year-round fishing in its rivers, streams, and lakes. According to a national survey taken in 2011 by the US Fish and Wildlife service, recreational fishing alone reels in $496 million in a year. For Arkansans who enjoy and rely on this fishing, tourism, and recreational industry, the invasive Northern Snakehead (Channa argus) is bad news. The fish is infamous for its snake-like shape, sharp teeth, and its ability to stay alive outside of the water for days by breathing air through its gills. The fish were brought to the United States from China, Russia, and Korea as aquarium pets or through live fish markets, and at some point escaped or were released into the larger stream system. They are prolific breeders with a large appetite, so, once they are introduced to a wild habitat it is easy for them to outcompete other organisms. They can disseminate unlike any other fish in Arkansas because of their ability to wriggle across dry land to another water system, and without the presence of local predators, they can become an apex predator in any ecosystem they encounter. What does this mean for the treasured native fish of Arkansas and the people who rely on them? Snakeheads cause a dramatic decrease in the variety and abundance of both game fish and the smaller fish that the other predators in the habitat need to survive. While there have been past efforts to combat the fish, as of yet the Snakeheads remain at large. If you would like to be involved in the ongoing process of the preventing the spread of Snakeheads in Arkansas’ waterways, report any Snakeheads you see to a local conservation agency such as the Arkansas Game and Fish Commission. For more information on invasive species in Arkansas check out this link.

 

 

California

The quagga mussel (Dreissena polymorpha) is a nonindigenous aquatic species that has made quite a splash in California. These organisms made their way to North America from Eastern Europe and Ukraine in the 1980s when ships with mussels attached to them docked in the Great Lakes. Since then, these tiny trespassers have hitched rides on water conveyance equipment and have found their way inland to states past the continental divide, impacting both the ecology and the economy of those places. They were first found in California in the San Justo Reservoir in 2008. They can produce 40,000 eggs per breeding cycle with multiple cycles every year and they are incredibly tolerant of a wide range of habitats, so they have the potential to have a significant impact on the environments in which they establish themselves. Quagga mussels consume huge amounts of phytoplankton, removing valuable nutrients from the water column before other species can take advantage of these resources. This lack of nutrients and habitat for other tide pool critters has the potential to reduce the biodiversity (the abundance and variety of life) of California shores. Boaters should keep in mind that when they are in quagga-mussel-infested water that the law requires them to thoroughly wash and dry all equipment afterwards to prevent spreading the nuisance. Cleaning equipment after use is the number one way you can help prevent the spread of mussels. If you are interested in more information on California’s invasive species, check out this link.

 

 

Colorado

New Zealand mudsnails (NZMS) have made their way to Colorado, where they compete with native snails for food and space. NZMS were are native to New Zealand and were first found in North America in the late 1980s in Idaho and Montana. Not only do NZMS compete with native mollusks, they also reduce food availability for native fish. The NZMS itself is not a food source for fish—they have a hard shell that allows them to pass through a fish gut unharmed. NZMS are transported primarily by humans, but can also hitch a ride on the feet of dogs and wildlife. These hearty snails can survive for up to 50 days on damp surfaces, giving them plenty of time to get to a new destination. To avoid transporting New Zealand mudsnails to new habitats, boaters and fishers should thoroughly wash and dry all equipment after recreational activities.  If you are interested in more information on Colorado’s invasive species, check out this link

 

 

Connecticut

Eurasian watermilfoil was first found in Connecticut in 1979, and this aquatic plant can now be found in more than 40 Connecticut lakes and ponds, as well as the Connecticut River. Eurasian watermilfoil is one of the most widely distributed invasive plans in the US, found in all of the contiguous 48 states. It is an aggressive competitor, and once introduced to a water body, it displaces native plants by forming dense canopies that reduce light availability and crowd out native species. This thick vegetation also degrades water quality, reduces oxygen in the water, and can lead to swimming, fishing, and boating restrictions in recreational waters.  If you want to help prevent this invasive species from displacing native plants and spreading its seeds to other bodies of water, make sure you clean off any fishing and boating equipment you use where there is Eurasian watermilfoil before you take it anywhere else. If you are interested in more information on Connecticut’s invasive species, check out this link.

 

 

Delaware

According to a national survey taken in 2011 by the US Fish and Wildlife service, recreational fishing alone reels in $496 million in a year. For Delaware residents who enjoy and rely on this fishing, tourism, and recreational industry, the invasive Northern Snakehead (Channa argus) is bad news. The fish is infamous for its snake-like shape, sharp teeth, and its ability to stay alive outside of the water for days by breathing air through its gills. The fish were brought to the United States from China, Russia, and Korea as aquarium pets or through live fish markets, and at some point escaped or were released into the larger stream system. They are prolific breeders with a large appetite, so, once they are introduced to a wild habitat it is easy for them to outcompete other organisms. They can quickly because of their ability to wriggle across dry land to another water system, and without the presence of local predators, they can become an apex predator in any ecosystem they encounter. What does this mean for the treasured native fish of Delaware and the people who rely on them? Snakeheads cause a dramatic decrease in the variety and abundance of both game fish and the smaller fish that the other predators in the habitat need to survive. The Delaware Department of Natural Resources asks that any possible snakehead catches in Delaware waters be reported. Do not release snakeheads back into the water—they should be killed or frozen for confirmation. For more information on invasive species in Delaware check out this link

 

 

Florida

Lionfish were first reported off the Florida Atlantic coast in 1985. Experts aren’t sure exactly how these fish were introduced to Florida’s coastal waters, but the invasion began with just a few fish. Since then, they have spread up the Atlantic coast to South Carolina, North Carolina, and Georgia, and have been found in areas along the Northern Gulf of Mexico. These predators eat native reef fish and can have far-reaching impacts, degrading the overall quality of reef habitat and killing native fish that keep algae in-check. Lionfish also compete with native predatory fish species, including grouper and snapper. Removing lionfish from waters by commercial and recreational divers is one of the best ways to control their populations in Florida’s waters. You can also report lionfish sightings by downloading the “Report Florida Lionfish App” on your smart device. And, you can eat them! Some restaurants in Florida are now serving commercially harvested lionfish. Learn more about lionfish in Florida, including how to cook with them.

 

 

Georgia

Water hyacinth (Eichhornia crassipes) threatens native plants and habitats in Georgia. Water hyacinth propagates so fast that one plant is able to cover 40 acres of water in one growing season. Touted as a pleasant ornamental, the species was brought to the United States from South America in 1884 and has since spread to other subtropical climates throughout North America. Water hyacinths may be attractive, but don’t let the pretty purple flowers fool you! These invaders cover the surface of the water which reduces light and oxygen availability for submerged plants. The plants that are being choked out by water hyacinth are vitally important to the ecosystem because they create habitat for fish and are the primary producers of the food web. When there are no longer any other healthy plants in an aquatic environment, other than the invasive plant, the abundance and variety of life is greatly reduced. Water hyacinth are also known to block water flow, hampering agriculture, fisheries, recreation, and hydropower. If you want to help prevent this invasive species from strangling out precious native organisms and spreading its seeds to other bodies of water, make sure you clean off any equipment you use where there is water hyacinth before you take it anywhere else. Check out this link for more information on invasive species in Georgia. 

 

 

Hawai'i

Native species found in Hawaii evolved under unique conditions where they did not have to compete with toxic plants, large carnivores, and other predators. This means that these species lost (or never evolved) defense mechanisms that may be found in their mainland relatives. When invasive species are introduced to island environments, they can wreak havoc on native populations that are not equipped to compete. Cattail—a familiar sight to many and one of the most common aquatic plants—is invasive in Hawaii. A single cattail flower can produce 250,000 seeds that disperse by wind and can remain viable in the soil for up to 100 years! Thick mats of cattails can crowd out native plants in Hawaii’s wetlands and displace native wildlife, including the Hawaiian stilt and koloa duck. The plants also encroach on taro fields, where their removal is costly to farmers. If you see cattail in Hawaii, report your sighting to the Hawaii Invasive Species Council.

 

 

Idaho

Eurasian watermilfoil is one of the most widely distributed invasive plans in the US, found in all of the contiguous 48 states. It is an aggressive competitor, and once introduced to a water body, it displaces native plants by forming dense canopies that reduce light availability and crowd out native species. This thick vegetation also degrades water quality, reduces oxygen in the water, and can lead to swimming, fishing, and boating restrictions in recreational waters.  If you want to help prevent this invasive species from displacing native plants and spreading its seeds to other bodies of water, make sure you clean off any fishing and boating equipment you use where there is Eurasian watermilfoil before you take the equipment anywhere else. If you are interested in more information on Idaho’s invasive species, check out this link.  

 

 

Illinois

Zebra mussels—named for the black and white striped pattern on their shells—have spread far and wide in the Great Lakes ecosystem over the past decade. They attach to any solid underwater object, including piers, pipes, plants, boat hulls, and even other mussels! When zebra mussels attach native mussels, they can make native mussels more vulnerable to stressors, including parasites and disease. Zebra mussels have voracious appetites; this means there is less food in the water for young fish, impacting sport and commercial fisheries. The mussels even impact infrastructure! Zebra mussel colonies have been to blame for reduced pumping capabilities and shutdowns at water treatment plants.  If you want to help contain these prolific invaders, follow the “clean, drain, and dry” method of making sure you don’t carry any mussels from one body of water to another. For more information on invasive species in Illinois check out this link.  

 

 

Indiana

Zebra mussels—named for the black and white striped pattern on their shells—have spread far and wide in the Great Lakes ecosystem over the past decade. They attach to any solid underwater object, including piers, pipes, plants, boat hulls, and even other mussels! When zebra mussels attach native mussels, they can make native mussels more vulnerable to stressors, including parasites and disease. Zebra mussels have voracious appetites; this means there is less food in the water for young fish, impacting sport and commercial fisheries. The mussels even impact infrastructure! Zebra mussel colonies have been to blame for reduced pumping capabilities and shutdowns at water treatment plants.  If you want to help contain these prolific invaders, follow the “clean, drain, and dry” method of making sure you don’t carry any mussels from one body of water to another. For more information on invasive species in Indiana check out this link

 

 

Iowa

Zebra mussels are a major concern in the Iowa Great Lakes. Named for the black and white striped pattern on their shells, these mussels have spread far and wide in the central United States over the past decade. They attach to any solid underwater object, including piers, pipes, plants, boat hulls, and even other mussels! When zebra mussels attach native mussels, they can make native mussels more vulnerable to stressors, including parasites and disease. Zebra mussels have voracious appetites; this means there is less food in the water for young fish, impacting sport and commercial fisheries. The mussels even impact infrastructure! Zebra mussel colonies have been to blame for reduced pumping capabilities and shutdowns at water treatment plants.  If you want to help contain these prolific invaders, follow the “clean, drain, and dry” method of making sure you don’t carry any mussels from one body of water to another. If you are interested in more information on Iowa’s invasive species, check out this link.

 

 

Kansas

That flash of silver leaping eight feet out of the water isn’t a bird, or a plane, but a silver carp, a type of Asian carp first brought to the US for its ability to consume high levels of phytoplankton in eutrophic waters. Since having escaped from this original fate, the silver carp is now found in more than 10 US states, most readily identified for its penchant for leaping high out of the water when startled, such as by the sound of a motorboat. When these heavy (up to 60 pounds) fish make impact with a boater traveling at high speeds, the aerial display goes from being a usual sight to an all-too common hazard. Aside from their “impact” on boaters, these fish can also affect aquatic species, by overeating phytoplankton that other, native, species also rely on as a source of food. If you catch an Asian carp in Kansas waters, do not release it back into the water. Learn more about identifying Asian carp, preventing their spread, and reporting sightings.

 

 

Kentucky

Eurasian watermilfoil is one of the most widely distributed invasive plans in the US, found in all of the contiguous 48 states. It is an aggressive competitor, and once introduced to a water body, it displaces native plants by forming dense canopies that reduce light availability and crowd out native species. This thick vegetation also degrades water quality, reduces oxygen in the water, and can lead to swimming, fishing, and boating restrictions in recreational waters. If you want to help prevent this invasive species from displacing native plants and spreading its seeds to other bodies of water, make sure you clean off any fishing and boating equipment you use where there is Eurasian watermilfoil before you take the equipment anywhere else. If you are interested in more information on Kentucky’s invasive species, check out this link.

 

 

Louisiana

Is it a beaver? A muskrat? No, it’s a nutria—also known as a “swamp rat.” Native to South America, nutria were imported to Louisiana for fur farming in the 1930s. Unfortunately, nutria were intentionally or accidentally released into Louisiana’s coastal marshes, where they have caused major damage. These herbivores like to feed on wetland plants and experts estimate they have damaged at least 80,000 acres of marsh. When nutria remove plants from the marsh surface, the underlying soil is exposed to erosion. If these exposed areas are not revegetated, they become open water and important habitat along the coast is lost. Louisiana is addressing the nutria problem through an incentive program for trappers to trap nutria. Learn more about the nutria and population control options.

 

 

Maine

Green crab populations are on the rise in some areas of Maine. This increase has occurred in tandem with rising ocean temperatures. Green crabs are aggressive, quick, and hungry—an adult green crab can eat up to 40 clams in a day, and even eats other crabs. The decline of the soft shell crab industry in New England has been attributed to green crabs, and these invaders have also reduced commercially-important populations of scallops, northern quahog, and Dungeness crabs. Green crab populations can be controlled and contained through trapping and fencing, and some chefs are even using them to make a delicious crab stock. If you are interested in more information on Maine’s invasive species, check out this link.

 

 

Maryland

According to a national survey taken in 2011 by the US Fish and Wildlife service, recreational fishing alone reels in $496 million in a year. For Maryland residents who enjoy and rely on this fishing, tourism, and recreational industry, the invasive Northern Snakehead (Channa argus) is bad news. The fish is infamous for its snake-like shape, sharp teeth, and its ability to stay alive outside of the water for days by breathing air through its gills. The fish were brought to the United States from China, Russia, and Korea as aquarium pets or through live fish markets, and at some point escaped or were released into the larger stream system. They are prolific breeders with a large appetite, so, once they are introduced to a wild habitat it is easy for them to outcompete other organisms. They can quickly because of their ability to wriggle across dry land to another water system, and without the presence of local predators, they can become an apex predator in any ecosystem they encounter. What does this mean for the treasured native fish of Delaware and the people who rely on them? Snakeheads cause a dramatic decrease in the variety and abundance of both game fish and the smaller fish that the other predators in the habitat need to survive. Northern snakeheads have become established in more than 60 miles of the Potomac River. If you catch a northern snakehead, kill it. Do not put it back into the water. Learn more about northern snakehead impacts and management.

 

 

Massachusetts

Green crabs have been in Massachusetts coastal waters for more than a century. They are aggressive, quick, and hungry—an adult green crab can eat up to 40 clams in a day, and even eats other crabs. The decline of the soft shell crab industry in New England has been attributed to green crabs, and these invaders have also reduced commercially-important populations of scallops, northern quahog, and Dungeness crabs. Green crab populations can be controlled and contained through trapping and fencing, and some chefs are even using them to make a delicious crab stock. If you are interested in more information on Massachusetts’ invasive species, check out this link.

 

 

Michigan

Zebra mussels—named for the black and white striped pattern on their shells—have spread far and wide in the Great Lakes ecosystem over the past decade. They attach to any solid underwater object, including piers, pipes, plants, boat hulls, and even other mussels! When zebra mussels attach native mussels, they can make native mussels more vulnerable to stressors, including parasites and disease. Zebra mussels have voracious appetites; this means there is less food in the water for young fish, impacting sport and commercial fisheries. The mussels even impact infrastructure! Zebra mussel colonies have been to blame for reduced pumping capabilities and shutdowns at water treatment plants.  If you want to help contain these prolific invaders, follow the “clean, drain, and dry” method of making sure you don’t carry any mussels from one body of water to another. For more information on invasive species in Michigan check out this link

 

 

Minnesota

Zebra mussels—named for the black and white striped pattern on their shells—have spread far and wide in the Great Lakes ecosystem over the past decade. They attach to any solid underwater object, including piers, pipes, plants, boat hulls, and even other mussels! When zebra mussels attach native mussels, they can make native mussels more vulnerable to stressors, including parasites and disease. Zebra mussels have voracious appetites; this means there is less food in the water for young fish, impacting sport and commercial fisheries. The mussels even impact infrastructure! Zebra mussel colonies have been to blame for reduced pumping capabilities and shutdowns at water treatment plants.  If you want to help contain these prolific invaders, follow the “clean, drain, and dry” method of making sure you don’t carry any mussels from one body of water to another. For more information on invasive species in Minnesota check out this link

 

 

Missisippi

In Mississippi, giant salvinia is giving a whole new definition to the classic “wet blanket”—when the salvinia is around, not much else can flourish. This aquatic fern forms dense, floating mats in freshwater waterbodies, and under ideal circumstances the mat can double in size in as little as one week. Aside from blocking out sunlight and atmospheric oxygen from reaching other aquatic organisms, the salvinia continues to threaten the rest of the ecosystem even in death, consuming large amounts of dissolved oxygen during the decomposition process after sections of the mat die and sink to the bottom of the water column. It’s not just the flora and the fauna that are impacted by this Brazilian invader, either—with mats reaching one meter in thickness, these ferns pose a serious navigational impediment to boaters. If you are interested in more information on invasive species in Mississippi, check out this link.

 

 

Missouri

That flash of silver leaping eight feet out of the water isn’t a bird, or a plane, but a silver carp, a type of Asian carp first brought to the US for its ability to consume high levels of phytoplankton in eutrophic waters. Since having escaped from this original fate, the silver carp is now found in more than 10 US states, most readily identified for its penchant for leaping high out of the water when startled, such as by the sound of a motorboat. When these heavy (up to 60 pounds) fish make impact with a boater traveling at high speeds, the aerial display goes from being a usual sight to an all-too common hazard. Aside from their “impact” on boaters, these fish can also affect aquatic species, by overeating phytoplankton that other, native, species also rely on as a source of food. Learn more about preventing the spread of invasive aquatic species in Missouri.  

 

 

Montana

New Zealand mudsnails (NZMS) are native to New Zealand and were first found in North America in the late 1980s in Idaho and Montana. Not only do NZMS compete with native mollusks, they also reduce food availability for native fish. The NZMS itself is not a food source for fish—they have a hard shell that allows them to pass through a fish gut unharmed. NZMS are transported primarily by humans, but can also hitch a ride on the feet of dogs and wildlife. These hearty snails can survive for up to 50 days on damp surfaces, giving them plenty of time to get to a new destination. To avoid transporting New Zealand mudsnails to new habitats, boaters and fishers should thoroughly wash and dry all equipment after recreational activities. For more information on invasive species in Montana, check out this link

 

 

Nebraska

That flash of silver leaping eight feet out of the water isn’t a bird, or a plane, but a silver carp, a type of Asian carp first brought to the US for its ability to consume high levels of phytoplankton in eutrophic waters. Since having escaped from this original fate, the silver carp is now found in more than 10 US states, most readily identified for its penchant for leaping high out of the water when startled, such as by the sound of a motorboat. When these heavy (up to 60 pounds) fish make impact with a boater traveling at high speeds, the aerial display goes from being a usual sight to an all-too common hazard. Aside from their “impact” on boaters, these fish can also affect aquatic species, by overeating phytoplankton that other, native, species also rely on as a source of food. Learn more about preventing the spread of invasive aquatic species in Nebraska.

 

 

Nevada

New Zealand mudsnails (NZMS) are native to New Zealand and were first found in North America in the late 1980s in Idaho and Montana. Not only do NZMS compete with native mollusks, they also reduce food availability for native fish. The NZMS itself is not a food source for fish—they have a hard shell that allows them to pass through a fish gut unharmed. NZMS are transported primarily by humans, but can also hitch a ride on the feet of dogs and wildlife. These hearty snails can survive for up to 50 days on damp surfaces, giving them plenty of time to get to a new destination. To avoid transporting New Zealand mudsnails to new habitats, boaters and fishers should thoroughly wash and dry all equipment after recreational activities. For more information on invasive species in Nevada, check out this link.

 

 

New Hampshire

Green crabs are aggressive, quick, and hungry—an adult green crab can eat up to 40 clams in a day, and even eats other crabs. The decline of the soft shell crab industry in New England has been attributed to green crabs, and these invaders have also reduced commercially-important populations of scallops, northern quahog, and Dungeness crabs. Green crab populations can be controlled and contained through trapping and fencing, and some chefs are even using them to make a delicious crab stock. If you are interested in more information on New Hampshire’s invasive species, check out this link.

 

 

New Jersey

Eurasian watermilfoil is one of the most widely distributed invasive plans in the US, found in all of the contiguous 48 states. It is an aggressive competitor, and once introduced to a water body, it displaces native plants by forming dense canopies that reduce light availability and crowd out native species. This thick vegetation also degrades water quality, reduces oxygen in the water, and can lead to swimming, fishing, and boating restrictions in recreational waters. If you want to help prevent this invasive species from displacing native plants and spreading its seeds to other bodies of water, make sure you clean off any fishing and boating equipment you use where there is Eurasian watermilfoil before you take it anywhere else. If you are interested in more information on New Jersey’s invasive species, check out this link.

 

 

New Mexico

Eurasian watermilfoil is one of the most widely distributed invasive plans in the US, found in all of the contiguous 48 states. It is an aggressive competitor, and once introduced to a water body, it displaces native plants by forming dense canopies that reduce light availability and crowd out native species. This thick vegetation also degrades water quality, reduces oxygen in the water, and can lead to swimming, fishing, and boating restrictions in recreational waters. If you want to help prevent this invasive species from displacing native plants and spreading its seeds to other bodies of water, make sure you clean off any fishing and boating equipment you use where there is Eurasian watermilfoil before you take it anywhere else. If you are interested in more information on New Mexico’s invasive species, check out this link

 

 

New York

Since their arrival to the scene in the 1990’s, the round goby have made quite an impression on the aquatic ecosystems of New York and the surrounding land areas of the Great Lakes region in both the United States and Canada. Originally from the Black Sea, these small grey fish made their way across the Atlantic in the ballast tank of a freighter ship, and soon began to put pressure on native populations of aquatic organisms. The round goby has been found to prey on lake trout eggs and local darters, reducing their populations in areas where the goby has become abundant. Don’t let the name fool you--the round goby presents such an intense predator pressure on the Great Lakes ecosystems that the state of Ohio has had shut down their smallmouth bass fishery during the months of May and June to keep the invaders away from the smallmouth nests. While this has meant that the state incurs a significant economic loss—up to 50% of the total smallmouth catch occurs in May and June—if left up to their own devices, the goby would be capable of consuming up to 4,000 of the smallmouth eggs within 15 minutes.  If you are interested in more information on New York’s invasive species, check out this link

 

 

North Carolina

In North Carolina, giant salvinia is giving a whole new definition to the classic “wet blanket”—when the salvinia is around, not much else can flourish. This aquatic fern forms dense, floating mats in freshwater waterbodies, and under ideal circumstances the mat can double in size in as little as one week. Aside from blocking out sunlight and atmospheric oxygen from reaching other aquatic organisms, the salvinia continues to threaten the rest of the ecosystem even in death, consuming large amounts of dissolved oxygen during the decomposition process after sections of the mat die and sink to the bottom of the water column. It’s not just the flora and the fauna that are impacted by this Brazilian invader, either—with mats reaching one meter in thickness, these ferns pose a serious navigational impediment to boaters. If you are interested in more information on invasive species in North Carolina, check out this link

 

 

North Dakota

That flash of silver leaping eight feet out of the water isn’t a bird, or a plane, but a silver carp, a type of Asian carp first brought to the US for its ability to consume high levels of phytoplankton in eutrophic waters. Since having escaped from this original fate, the silver carp is now found in more than 10 US states, most readily identified for its penchant for leaping high out of the water when startled, such as by the sound of a motorboat. When these heavy (up to 60 pounds) fish make impact with a boater traveling at high speeds, the aerial display goes from being a usual sight to an all-too common hazard. Aside from their “impact” on boaters, these fish can also affect aquatic species, by overeating phytoplankton that other, native, species also rely on as a source of food. If you are interested in more information on invasive species in North Dakota, check out this link.

 

 

Ohio

Zebra mussels—named for the black and white striped pattern on their shells—have spread far and wide in the Great Lakes ecosystem over the past decade. They attach to any solid underwater object, including piers, pipes, plants, boat hulls, and even other mussels! When zebra mussels attach native mussels, they can make native mussels more vulnerable to stressors, including parasites and disease. Zebra mussels have voracious appetites; this means there is less food in the water for young fish, impacting sport and commercial fisheries. The mussels even impact infrastructure! Zebra mussel colonies have been to blame for reduced pumping capabilities and shutdowns at water treatment plants.  If you want to help contain these prolific invaders, follow the “clean, drain, and dry” method of making sure you don’t carry any mussels from one body of water to another. For more information on invasive species in Ohio, check out this link

 

 

Oklahoma

In Oklahoma, not all that glitters is gold. One flash of gold to avoid in particular, is golden algae, a type of algae that occurs in brackish waters, and when stressed, can produce toxins that have been responsible for massive fish kills. With at least 7.6 million fish dead in Texas alone due to this invasive species, golden algae has the potential to make lasting economic and ecological impacts on its surrounding waterbodies. Currently, the algae is concentrated in the waters around the Red River basin, meaning that southern Oklahoma should be on high alert. For more information on invasive aquatic species in Oklahoma and how to help stop their spread, check out this resource from the Oklahoma Water Resource Board.

 

 

Oregon

One of the more unexpected impacts of the tsunami that struck Japan in 2011 has been the blowback—large pulses of water carrying marine debris across the ocean. Included in the debris were more than 90 species found to have traveled to Oregon’s shores. Some of these species were native to the eastern Pacific, and now pose a threat to the native communities of the Pacific Northwest, such as the northern Pacific seastar, the Japanese shore crab, and Wakame brown kelp algae. Lacking native predators, these species have the potential to make a lasting impact on the aquatic habitats of Oregon, and the state has asked residents to be vigilant. If you find marine debris with living organisms attached, take a photo and send the image with your location to beach.debris@state.or.us. For more information on how to safely dispose of these items, as well as what to do if the item is too large to move, consult this guide from the Oregon Department of Fish and Wildlife.

 

 

Pennsylvania

Under the surface (or above it in some cases), lies one of Pennsylvania’s least-wanted species—the hydrilla. This invasive, submerged aquatic plant also referred to as “water thyme” first made its debut in the Keystone State in the late 1990’s, after being imported to the United States in the 1950s from the Indian subcontinent for decorative use in aquariums. Growing aggressively, this plant elongates upwards from the bottom of the water column, and then upon reaching the surface of the water, grows horizontally, forming thick mats at the surface that block light from reaching aquatic species below. The presence of the hydrilla has been found to correlate with reduced weight and size of sportfish, implying that these fish were unable to find enough food with hydrilla choking out native aquatic plants. Additionally, the presence of hydrilla mats can impede boating, swimming, and fishing, as well as block access to water typically used for power generation and agricultural irrigation. To learn more about invasive aquatic species in Pennsylvania and get tips for how to help stop their spread, check out this resource from the Pennsylvania Fish and Boat Commission.

 

 

Rhode Island

Rhode Island is home to something of a celebrity in the invasive species world—the green crab, one of the most successful invasive predators in the world, with populations established on five continents. Having arrived to North America in 1817, the crabs have had ample time to establish themselves, aided by their ability to withstand a wide range of salinities and water temperatures. Once embedded in a community, the crabs have been found to prey heavily on local clam and scallop populations, even attacking nearby dungeness crabs. The pressure these crabs put on local clam populations has been so intense that it has been responsible for the closure of New England soft-shell clam fisheries. Invasive crabs aren’t Rhode Island’s only worry—to learn how to help stop the spread of invasive aquatic plants, take a look at this guide from the Rhode Island Department of Environmental Management.

 

 

South Carolina

Island applesnails have taken up residence in the palmetto state, but locals hope that it won’t be a permanent one. These large, pink to red snails eat a wide variety of plant materials, giving them an edge in over consuming native plant populations, out-competing native snail groups and altering the food web in affected areas. Local snails aren’t the only ones impacted—these snails can be disease vectors, and as such should not be touched by bare skin. If you see an invasive snail in South Carolina waters, take a photo and report the sighting to the South Carolina Department of Natural Resources via email. Learn more about invasive species in South Carolina and what you can do to help stop the spread of these aquatic hitchhikers at the South Carolina Department of Natural Resources page.

 

 

South Dakota

That flash of silver leaping eight feet out of the water isn’t a bird, or a plane, but a silver carp, a type of Asian carp first brought to the US for its ability to consume high levels of phytoplankton in eutrophic waters. Since having escaped from this original fate, the silver carp is now found in more than 10 US states, most readily identified for its penchant for leaping high out of the water when startled, such as by the sound of a motorboat. When these heavy (up to 60 pounds) fish make impact with a boater traveling at high speeds, the aerial display goes from being a usual sight to an all-too common hazard. Aside from their “impact” on boaters, these fish can also affect aquatic species, by overeating phytoplankton that other, native, species also rely on as a source of food. Learn more about preventing the spread of invasive aquatic species in South Dakota, as well as important information such as how to report a sighting of an invasive species or where to find your closest boat wash location, by visiting the state’s website on invasive aquatic species.

 

 

Tennessee

That flash of silver leaping eight feet out of the water isn’t a bird, or a plane, but a silver carp, a type of Asian carp first brought to the US for its ability to consume high levels of phytoplankton in eutrophic waters. Since having escaped from this original fate, the silver carp is now found in more than 10 US states, most readily identified for its penchant for leaping high out of the water when startled, such as by the sound of a motorboat. When these heavy (up to 60 pounds) fish make impact with a boater traveling at high speeds, the aerial display goes from being a usual sight to an all-too common hazard. Aside from their “impact” on boaters, these fish can also affect aquatic species, by overeating phytoplankton that other, native, species also rely on as a source of food. Learn more about invasive aquatic species in Tennessee. 

 

 

Texas

In Texas, giant salvinia is giving a whole new definition to the classic “wet blanket”—when the salvinia is around, not much else can flourish. This aquatic fern forms dense, floating mats in freshwater waterbodies, and under ideal circumstances the mat can double in size in as little as one week. Aside from blocking out sunlight and atmospheric oxygen from reaching other aquatic organisms, the salvinia continues to threaten the rest of the ecosystem even in death, consuming large amounts of dissolved oxygen during the decomposition process after sections of the mat die and sink to the bottom of the water column. It’s not just the flora and the fauna that are impacted by this Brazilian invader, either—with mats reaching one meter in thickness, these ferns pose a serious navigational impediment to boaters. If you see this species in Texas waters, take a photo and report it to texasinvasives.org. Learn more about preventing the spread of invasive species in Texas.

 

 

Utah

Though it’s small, don’t let looks deceive you—while the Asian clam measures fewer than five centimeters across, this invader has caused nuclear reactors to temporarily close…several times. The Asian clam’s ability to cause biofouling, or to attach itself in large numbers to man-made structures has caused billions of dollars in maintenance needs to power and water infrastructure across the country, as these facilities work to remove the organisms from their structures. Water that is drawn in by power plants for cooling purposes also pulls in the organism’s larva, and once inside the plant, the mussels can attach themselves to the walls of the facility, and as they grow their large numbers can impede the flow of water, reducing the efficiency of power generation at the plant and even compromising firefighting equipment. To learn more about invasive aquatic species in Utah, check out the Utah Division of Wildlife Resources’ page on the issue, and make sure you’re not inadvertently spreading aquatic hitchhikers.

 

 

Vermont

Looking like a miniature lilypad, the European frogbit traveled a long way to get to Vermont from its native Europe. After escaping ornamental cultivation in Ottawa in the 1930’s, this floating plant traveled down to Lake Superior and eventually on to New York, Michigan, Washington, and Vermont, possibly aided in this dispersal by motor boats. Don’t let looks deceive you—the frogbit is bad news for native aquatic populations, which can suffer from lack of sunlight if a mat of frogbit floats into the area and expands with its signature “runners,” or stolons. These viney appendages can tangle themselves into boat propellers, trap sediment and suffocate aquatic life, and even affect local fauna. If you spot an invasive species in the state of Vermont you can report it to the Department of Environmental Conservation, and if you’re passionate about the issue, consider volunteering to become a Vermont Invasive Patroller! Learn more about invasive aquatic species in Vermont.

 

 

Virginia

In Virginia, the rapa whelk has slowly crept out of control. This invasive, predatory snail is originally from the Sea of Japan and the East China Sea, but may have hitched a ride to the US in the tank of a ballast ship. Discovered in 1999, the rapa whelk may pose a threat to the native oyster, clam, and mussel populations in the Chesapeake Bay—the main diet of the rapa whelk is other mollusk species, which it smothers by wrapping its body around the hinged part of the prey organism’s shell and feeding between the open valve. The Virginia Institute of Marine Science is currently studying the potential impacts of this invader, but to learn more about invasive aquatic species in the Commonwealth, you can review “Twelve Invasive Species of High Concern in Virginia.”

 

 

Washington

For the state of Washington, one invasive plant has given certain waterbodies a particular “pull” that anglers, boaters, and other aquatic species may find difficult to resist—the Brazilian elodea. While this freshwater plant may have originally been brought to the area as an aquarium filler, it can grow far beyond the dimensions of a home fish tank, with its stems reaching heights up to 18 feet to stretch towards the water’s surface. These plants can form dense mats that trap sediment, smothering aquatic species, blocking the passage of juvenile salmon, and presenting obstacles to water recreators. If you come across this invasive aquatic plant, report it to the Washington Invasive Species Council. Learn more about invasive aquatic species in the state of Washington. 

 

 

West Virginia

If the water in your local stream system is looking a little sickly, you may have a freshwater algae referred to as “rock snot” to blame. Commonly called Didymo as an abbreviation from Didymosphenia geminata, this algae attaches to rocks in the bottom of streambeds, and can form thick, slimy-looking white, yellow, or brown mats in streams and rivers, smothering aquatic vegetation and limiting fishing access. While Didymo is relatively new in West Virginia, first found in 2008, the Department of Natural Resources is already hard at work to spread the word of this invader. You can check out the WV DNR’s resources on how to combat Didymo here, and click here to learn more about invasive species in West Virginia

 

 

Wisconsin

Since their arrival to the scene in the 1990’s, the round goby have made quite an impression on the aquatic ecosystems of Wisconsin and the surrounding land areas of the Great Lakes region in both the United States and Canada. Originally from the Black Sea, these small grey fish made their way across the Atlantic in the ballast tank of a freighter ship, and soon began to put pressure on native populations of aquatic organisms. The round goby has been found to prey on lake trout eggs and local darters, reducing their populations in areas where the goby has become abundant. Don’t let the name fool you—the round goby presents such an intense predator pressure on the Great Lakes ecosystems that the state of Ohio has had shut down their smallmouth bass fishery during the months of May and June to keep the invaders away from the smallmouth nests. While this has meant that the state incurs a significant economic loss—up to 50% of the total smallmouth catch occurs in May and June—if left up to their own devices, the goby would be capable of consuming up to 4,000 of the smallmouth eggs within 15 minutes.  To learn more about how to help prevent the spread of invasive aquatic species in Wisconsin such as the round goby, check out these resources from the Wisconsin Department of Natural Resources, and consider joining the Citizen Lake Monitoring Network, or becoming a Clean Boats, Clean Waters Volunteer

 

 

Wyoming

The issue of invasive aquatic species in the United States hasn’t always been as well understood as it is today; at some points in US history, there were times when high volumes of exotic species were intentionally introduced to our lakes, rivers, and waterways for the purpose of creating stocks for food or recreational activities. In the case of the common carp, this exotic fish was spread throughout the country in the late 1800s with the help of the US Commission of Fish and Fisheries, which imported the carp from Germany and stocked it in fisheries, rivers, and ponds across the country, aided by state fish commissions who would sometimes release the fish from railroad tank cars at bridge crossings directly into water bodies. Today, the fish are regarded as pests in Wyoming because of the impact they have on water clarity and aquatic vegetation. While feeding, carp will uproot aquatic vegetation and stir up the sediment at the bottom of the water column. Aside from destroying some of the plants themselves, this clouding of the water reduces the amount of sunlight available to the rest of the aquatic plants, impacting not only the flora themselves but also the aquatic species that rely on the vegetation for food, shelter, and spawning and nursery grounds. In addition to their impact on the aquatic landscape, the carp have been found to prey on the eggs of native fish species in the area, such as the critically endangered razorback sucker. To learn more about preventing the spread of invasive aquatic species in Wyoming, check out this advice from the Wyoming Game & Fish Department

 

SOURCES

Alabama

Alaska

Arizona

Arkansas

California

Colorado

Connecticut

  • Connecticut Department of Energy and Environmental Protection. 2015. “Examples of Aquatic Invasive Species In Connecticut.” Accessed September 14, 2016. http://www.ct.gov/deep/cwp/view.asp?A=2702&Q=474710
  • Pfingsten, I.A., L. Berent, C.C. Jacono, and M.M. Richerson. 2016. Myriophyllum spicatum. USGS Nonindigenous Aquatic Species Database, Gainesville, FL. Accessed September 14.

http://nas.er.usgs.gov/queries/FactSheet.aspx?SpeciesID=237

Delaware

Florida

Georgia

Hawaii

Idaho

Illinois

Indiana

Iowa

Kansas

Kentucky

Louisiana

Maine

Maryland

Massachusetts

Michigan

Minnesota

Mississippi

Missouri

Montana

Nebraska

Nevada

New Hampshire

New Jersey

  • New Jersey Department of Environmental Protection. n.d. “New Jersey Non-Native Plants: Eurasian Watermilfoil.” Accessed September 14, 2016. http://www.nj.gov/dep/njisc/Factsheets/e_waterm.pdf
  • Pfingsten, I.A., L. Berent, C.C. Jacono, and M.M. Richerson. 2016. Myriophyllum spicatum. USGS Nonindigenous Aquatic Species Database, Gainesville, FL. Accessed September 14.

http://nas.er.usgs.gov/queries/FactSheet.aspx?SpeciesID=237

New Mexico

  • Pfingsten, I.A., L. Berent, C.C. Jacono, and M.M. Richerson. 2016. Myriophyllum spicatum. USGS Nonindigenous Aquatic Species Database, Gainesville, FL. Accessed September 14.

http://nas.er.usgs.gov/queries/FactSheet.aspx?SpeciesID=237

New York

North Carolina

North Dakota

Ohio

Oklahoma

Oregon

Pennsylvania

Jacono, C.C., M.M. Richerson, V.H. Morgan, E. Baker, and J. Li. 2015. Hydrilla verticillata. USGS Nonindigenous Aquatic Species Database, Gainesville, FL, and NOAA Great Lakes Aquatic Nonindigenous Species Information System, Ann Arbor, MI. Accessed September 16.
http://nas.er.usgs.gov/queries/greatlakes/FactSheet.aspx?SpeciesID=12&Potential=Y&Type=2&HUCNumber=

Rhode Island

South Carolina

South Dakota

Tennessee

Texas

Utah

Vermont

Virginia

Washington

West Virginia

Wisconsin

Wyoming

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