Surely a Sea Lamprey….right?

Double Check Those Lamprey; Wisconsin has Native Lamprey Too

Many Wisconsin anglers are catching fish left, right, and center as we near mid-summer. But sometimes with those fish, there are reports of sea lamprey attached to fish. Even in places where the sea lamprey isn’t known to have reached, including Lake Winnebago. But anglers are often surprised to hear that Wisconsin waters play host to native lamprey. Take a minute to learn how to identify our native lamprey so next time you catch a fish with a lamprey, you’ll know if it’s native or invasive.

Native Lamprey vs. Sea Lamprey

There are four native freshwater lamprey that can be found in Wisconsin. Of these four, two are parasitic and might be on your next fish. Each species of lamprey have different physical characteristics that can help you figure the lamprey you’re seeing. Check out the chart below to see how our native species differ from the invasive sea lamprey.

Click the image to enlarge

If you’re looking for key characteristics to determine if you’ve caught a sea lamprey, take a look at the top fin of the lamprey. If the long fin on the back of the lamprey is split into two (two dorsal fins), there’s a good chance you’ve caught a sea lamprey.

The most common lamprey in the Winnbeago lake system is the native Chestnut Lamprey. To learn more about this native lamprey, check out this Fox-Wolf Species Spotlight article.

To learn more about the invasive sea lamprey, Fox-Wolf’s AIS Spotlight has the info you’ll need!