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…
