Invasive Species Fact Sheets
Invasive species can disrupt the food web, outcompete native species for food and habitat, and change an environment forever. All of the species below could pose a threat to the Great Lakes. Some are well-established, and others are just arriving. Each fact sheet includes a description, photos and a summary of potential problems caused by these invaders.


Fish

Alewife (Alosa pseudoharengus)
When springtime spawning stress (along with temperature fluctuations and the fish's lack of complete adaptation to fresh water) cause die-offs, Great Lakes beaches can be covered with dead and dying fish. Read more...


Bighead Carp (Aristichthys nobilis)
The big head carp does not have a true stomach so it must constantly eat. Read more...


Black Carp (Mylopharyngodon piceus)
This long-lived (15 years or more) fish feeds heavily on snails and mussels, potentially posing a threat to native mollusks. Read more...


Blueback herring (Alosa aestivalis)
These silvery fish are not yet established in the Great Lakes, but if they do become established they could slow the recovery of native fish such as lake trout and sisco. Read more...


Eurasian Ruffe (Gymnocephalus cernuus)
The ruffe has a lack of natural predators which creates the potential to displace other species in newly invaded areas and to cause the native fish populations to decrease. Read more...


European Rudd (Scardinius erythrophthalmus)
Probably introduced as a bait-bucket release, the European rudd has been reported in at least 22 states. Read more...


Grass Carp (Ctenopharyngodon idella)
This widely established invasive competes with native species for food and shelter. Each fish can eat up to 100% of its body weight per day in aquatic plants. Read more...


Northern snakehead (Channa argus)
This voracious predator has few natural enemies and is very difficult to eradicate once it's established. Read more...


Rainbow Smelt (Osmerus mordax)
This slender fish shimmers colorfully in water, but it fades quickly out of water and smells of cucumbers. They've been known to decimate walleye populations. Read more...


Redear sunfish
Redear sunfish compete with the native pumpkinseed for food (both prefer snails). Read more...


Round Goby (Apollonia melanostomus)
Round gobies reproduce very quickly, up to six times in a summer, and populations increase very quickly. Read more...


Silver carp (Hypophthalmichthys molitrix)
How to prevent an invasion of Asian carp into the Great Lakes has been one of the most controversial topics in the management of aquatic invasive species. Read more...


Sea Lamprey
The sea lamprey is one of the best-known aquatic invasive species, and perhaps the most disgusting. Read more...


Tench (Tinca tinca)
This stocky fish can really stir things up--and when it does stir up the muddy bottom of a lake, the sediments can sink back down and suffocate the eggs and newly hatched fish of native species. Read more...


Threespine stickleback (Gasterosteus aculeatus)
This prickly little fish preys on native species and can out-compete them for food and habitat. Read more...


Tubenose Goby (Proterorhinus marmoratus)
The tubenose goby is not as aggressive as the round goby, but it may still displace native species. Read more...


White Perch (Morone americana)
White perch are predacious and opportunistic feeders, often feeding on the eggs of walleye. Read more...


Mollusks

Asiatic Clam (Corbicula fluminea)
Asiatic clams are capable of self-fertilization, and one clam can lay up to 70,000 eggs a year. Read more...


Banded Mystery Snail (Viviparus georgianus)
This invasive snail can serve as a host for parasites that may infect fish and other wildlife, compete with native snails for food and habitat, and cause mortality of largemouth bass embryos. Read more...


Chinese Mystery Snail (Cipangopaludina chinensis malleata)
The mystery snails (both Chinese and banded) don't come from eggs. They spring forth fully formed--mysterious indeed. Read more...


Faucet Snail (Bithynia tentaculata)
These small snails are hosts to parasites that have caused the deaths of tens of thousands of diving ducks in the Great Lakes region. Read more...


Golden mussel (Limnoperna fortunei)
This native of SE Asia and China has caused major problems in South America, and it may be coming to North America via ballast water. Read more...


New Zealand Mud Snail (Potamopyrgus antipodarum)
The New Zealand mud snail has no predators outside of New Zealand. Read more...


Quagga Mussel (Dreissena rostriformis bugensis)
Appearing in the Great Lakes later than the zebra mussel, quagga mussels may present even more of a challenge. Read more...


Zebra Mussels (Dreissena polymorpha)
The annual cost on the Great Lakes to control the zebra mussels in water intake pipes is $250 million. Read more...


Plants

Brazilian elodea (Egeria densa)
Brazilian elodea is a popular aquarium plan that has found its way into the Great Lakes region. It crowds out native aquatic plants, degrades fish and waterfowl habitat and creates breeding grounds for mosquitoes. Read more...


Curlyleaf pondweed (Potamogeton crispus)
This strange aquatic invasive dies off in the middle of summer--when everything else it at its peak--but it starts the season off with a major growth spurt. Read more...


Eurasian Watermilfoil (Myriophyllum spicatum)
Just a single two-inch fragment of Eurasian watermilfoil is all it takes to start a new plant. Read more...


European Frogbit (Hydrocharis morsus-ranae)
Mats of frog-bit can become so thick that boat traffic can be affected by the frog-bit tangling around boat props so that the boats can no longer move in the water. Read more...


Hydrilla (Hydrilla verticillata)
A submerged aquatic plant, hydrilla is extremely fast growing and can clog waterways and suffocate native plants. Read more...


Phragmites (Common Reed or Phragmites australis)
Common reed has replaced much of the naturally diverse wetland plant population. Read more...


Purple Loosestrife (Lythrum salicaria)
Purple loosestrife arrived in North America as early as the 1800s. Read more...


Water Chestnut (Trapa natans)
This aquatic invasive has dangerously sharp-spined nuts and has colonized Lake Ontario and a significant part of the northeastern U.S. Read more...


Zooplankton & Crayfish

Bloody-Red Shrimp (Hemimysis anomala)
The bloody-red shrimp is one of our most recent ballast water invaders. Read more...


Fishhook waterflea (Cercopagis pengoi)
These tiny little invasive zooplankton form clumps that can look and feel like gelatin or wet cotton. Read more...


Red Swamp Crayfish (Procambarus clarkii)
This invasive crayfish can be a host for parasites and diseases, and it aggressively competes with native crayfish and other species for food and habitat. Read more...


Rusty Crayfish (Orconectes rusticus)
The rusty crayfish is a very aggressive species that often displaces native crayfish. Read more...


Spiny waterflea (Bythotrephes longimanus)
Waterfleas can clump together on fishing lines, nets and other gear, and they disrupt the food web. Read more...

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