Rainbow Smelt

Rainbow Smelt (RWS)

Where are RWS from and how did they get here?
RWS are an anadromous species (naturally living in salt water, and moving to freshwater to spawn) native to the East Coast near New Jersey. They were stocked into a Michigan lake to act as a “feeder fish” for larger fish species, and spread from there via connecting waterways.

How do I identify RWS?
RWS have slender and cylindrical body shapes. They are silvery, and some say they smell of cucumbers when fresh and still alive. They have an anal fin and an adipose fin, and a deeply forked tail. They have visible teeth when their mouth is open
Please contact our Water Program Coordinator if you think you have found RWS.

RWS- note the fins and long slender body

RWS have visible, sharp teeth when their mouths are open

How do RWS affect Wisconsin water bodies?
RWS cause declines in native fisheries, especially in yellow perch and ciscos. They compete for food sources, and also prey on young-of-year fish.

What can be done once RWS enter a water body?
Little can be done to remove a RWS population once it establishes in a water body. The best treatment is to prevent them from establishing in the first place. It is important to drain all water from boats before leaving landings, and to never dump bait buckets into lakes.

Additional Resources

Manitowish Waters Lakes Association

Wisconsin DNR Aquatic Invasive Species

Citizen Lake Monitoring Network: Get Involved!

Great Lakes Indian Fish & Wildlife Commission (GLIFWC) Invasive Species Area Maps

US Geological Survey Invasive Species Research

Vilas County Land and Water Conservation Department

Invasive Plants Association of Wisconsin



Available for loan.

Lake Plants You Should Know- A Visual Field Guide. University of Wisconsin- Extension.

Aquatic Plants of the Upper Midwest- A Photographic Field Guide To Our Underwater Forests.Written by: Paul Skawinski.

Through the Looking Glass- A Field Guide to Aquatic Plants. Written by: Susan Borman, Robert Korth, and Jo Temte.

Saving Our Lakes and Streams. Written by: James A. Brakken.

Your Help Is Needed

Curly leaf pondweed has been found in the Manitowish Waters Chain. Please keep your eyes open and let us know if you see this aquatic invasive plant along your shorelines or docks. Additionally, please check your boats and props to prevent the spread!

Citizen AIS Lake Monitoring

Join a crew to search for suspicious-looking species (plant or animal). Keep your eyes peeled and report any sightings to us.

Clean Boats Clean Waters

Educate boaters at landings and inspect boats and trailers.

Volunteer today, to protect our waters tomorrow.

Email: water@discoverycenter.net
Phone: (715) 543-2085

AIS of the Month

September: Mystery Snails

August: Eurasian Water Milfoil

July: Purple Loosestrife

June: Curly Leaf Pondweed