Invasive Species

Round Gobies
Apollonia melanostomus, Asamiko-asaawens

These tough little bottom-dwellers likely rode to the Great Lakes in the ballast tanks of ships coming from Europe and Asia. With frog-like eyes and thick lips, they find and devour the eggs and fry of native fish. They also edge out other fish by reproducing several times a year. Their unusual fused pelvic fin anchors them to rocks.

Sea Lamprey
Petromyzon marinus, Onaga’eboyenh

These “vampires” are primitive fish of the Atlantic Ocean that snuck into Lake Superior in 1938 after the Welland Canal let them past Niagara Falls. Their toothed tongue and round mouth allows them to suck blood and fluids out of other fishes. An adult sea lamprey can swallow 40 pounds of fish before it dies. Each year, controlling these snaky invaders costs $$$ millions.

Rusty Crayfish
Orconectes rusticus, Gidagi-ashaageshiinh

Likely, these lobster relatives came west from the Ohio River Basin to Lake Superior in anglers’ bait buckets. They can harm fish populations by eating fish eggs and fry, and by chomping up the aquatic vegetation where small creatures cower. Rusty crayfish look like native crayfish except they are larger and meaner. They also make great crawfish jambalaya.

Eurasian Ruffe
Gymnocephalus cernuus, Ozhaashi-asaawens

This spiky fish presumably crossed the Atlantic Ocean in ballast water carried by ships coming from Europe and Asia to Lake Superior. Eurasian ruffe compete with other fish for food and space. The invaders resemble native yellow perch, but they’re not big enough to serve for dinner. A ruffe has a continuous dorsal fin and a slightly downturned mouth (what a grump!).

Zebra Mussels
Dreissena polymorpha, Bepeshi-es

These remarkably fertile and remarkably clingy shellfish spread from Europe to the Great Lakes in the ballast water of ships. Now they’re also clogging water intake pipes and attaching to boat motors and hard surfaces in North America’s inland waters. They disrupt fisheries, smother native mussels, and, when they die, their sharp shells litter beaches. They look like small clams with zebra striping (usually).