Snapshot Day Volunteers Expand Known Range of Aquatic Invasive Species

Posted on
A large group of people stand in the shade on a sunny day.

Volunteers at the 2026 Madison Snapshot Day.

On August 8, 2026, almost 200 people who love Wisconsin’s waters came together for the 13th annual Aquatic Invasive Species Snapshot Day—a statewide search for aquatic invasive species (AIS). From rivers and streams to lakes and wetlands, volunteers fanned out across 125 different waterbodies in Wisconsin, helping monitor the health of the places they care about most.

The event, coordinated by UW—Madison Extension in partnership with the Wisconsin Department of Natural Resources (WDNR), Extension Lakes, and dozens of county and nonprofit organizations, is part science, part stewardship, and part community gathering.

A light blue grey background. At the top of the graphic is the number 125 in big white letters. Next to the number to the right is smaller white text that reads "Different waterbodies monitored..." In the middle right, there is white text with the number 48 and beneath the number is white text that reads "Rivers & Streams". In the bottom left is number 72 with white text beneath it that reads Lakes. Starting in the middle top (but beneath the 125 text) is a drawing/graphic design of river and tributaries in a teal blue with specks of green represented plants. The stream flows from the middle of the image all the way to the bottom of the image, wrapping around the numbers 48 and 72.

Building connection through AIS

Volunteers started their morning at one of 26 meeting stations across the state, where they learned how to spot invasive species like Eurasian watermilfoil, zebra mussels, and freshwater golden clams. After a hands-on training in identification and search protocols, volunteers headed out in small groups to survey 161 sites throughout Wisconsin. Any potential findings were documented and shared with the Wisconsin Department of Natural Resources, supporting ongoing efforts to detect, control, and manage these species.

For many, the day was about more than data collection. It was about connection, not only to the natural world, but to each other. One participant shared:

“It was really wonderful to do this with friends. What an amazing way to connect with friends– doing something useful, meaningful, and important. I loved it. Can’t wait to do it again.”

A group of people stand on a sidewalk. The two people in the foreground are standing facing each other holding a green AIS in their hands. The people in the background stand around them looking at the AIS. The background is green foliage.
Volunteers at the Polk County Snapshot Day learn to identify AIS.

Another volunteer reflected on the sense of purpose that comes from contributing:

“Being an avid outdoorsman, I cherish our state’s natural resources and want to protect them. The opportunity to really delve into what is really in our outdoor environment gives me an even greater appreciation for it. It’s very enriching to meet and work with like-minded people for a common cause.”

Protecting our waters

This year’s findings highlighted the importance of that work: AIS were detected at 61% of monitoring sites. All the data collected feeds into Wisconsin’s statewide water quality database, SWIMS, helping resource managers track invasive species and plan for the future.

Horizontal bar chart of AIS identified during 2026 snapshot Day and previously reported AIS. The background is a light orange. The bars are orange and teal. Teal represents where AIS were previously reported, where orange represents new sitings of AIS at this locations. The teal overlaps the orange bar at different lengths. The left of the bars is corresponding white text with the names of AIS. At the ends of the bars to the right are white numbers representing how many AIS were found.
*as of 9/3/2026, data have not been fully finalized in WDNR’s SWIMS database, awaiting Resource of Interest creation and management by DNR. Reported numbers may vary slightly in future. Other species reported included: reed canary grass, narrow-leaf and hybrid cattails, and hybrid water milfoil
A pale pastel orange background. Left half of image: In the left top is a group of people standing 10 people standing in a triangle formation (1 person in front, two people behind them, etc.) Each person is different shade of blue based on what line they are in. In the left bottom is a group of people standing 10 people standing in a triangle formation (1 person in front, two people behind them, etc.) Each person is different shade of orange based on what line they are in. Right hand side: There is white text stacked on top of each other in a column. The order from top to bottom is: 150 volunteers, plus sign, 28 leaders, equal sign, 178 participants.

Beyond the science, Snapshot Day is a reminder of what can be accomplished when people come together. As one volunteer put it:

“Snapshot [D]ay was a great opportunity to learn about aquatic invasive species and enjoy some beautiful natural areas.”

To every volunteer, partner organization, and site leader—thank you for making this year’s Snapshot Day a success! Your energy and dedication keep Wisconsin’s waters healthy for everyone.

Want to see more highlights from the day?

Scroll through some “snapshots” below, and if your group wasn’t featured, or you have photos to add, reach out to Rivers Educator Emily Heald at emily.heald@wisc.edu.

Follow the UW—Madison Extension AIS Program on Facebook for updates and AIS news: facebook.com/uwaisprogram

A man in black shorts and green long sleeve stands in brownish river water on a clear blue sunny day. His back is to the camera.
Chippewa County
Two adults and young child crouch in a bare patch of a grassy areas. They are looking at two trays on the ground filled with water and specimens they have collected. It is bright sunny day.
Dane County
A man in a long sleeve baby blue shirt wearing sunglasses holds a rake head with white rope attached to it. The rope is coiled around an orange roll. A man with a dark grey shirt and khaki shorts stands next to him. The two people are standing on the rocky banks of a lake. The lake is behind them. It is sunny.
Door County
A white bucket filled halfway with water. In the water are green plants. The bucks is on a brown bench. In the lower left hand corner is a hand holding a round sticker. The sticker has an orange border and teal center. In the center of the sticker are black binoculars.
Douglas County
A shadow of a person projected onto clear lake water on a sunny day.
Forest County
Two people in hats and long sleeves sit on a grassy patch with their backs facing the camera. They are outside on a sunny day surrounded by green foliage.
Iowa County
A person stands halfway facing the camera on the left hand side holding a clump of dirt and grass. In the middle bottom a young girl with a blue shirt crouch looking at the camera. In the middle stands a person in a white hat and bright yellow jacket turned sideways. They are all outside surrounding by grass and trees.
Jefferson County
A large group of peope pose fo a photo in front of a small yard sign. They are standing on grass. In the background you can see a river with trees on the bank and a cloudy sky.
Polk County
A group of kids stand on a floating plastic dock on a sunny day. They are holding nets in water that has green algae in it. In the background you can see the lake, trees, and a blue sky.
Walworth County
Photo of an arm holding a clipboard horizontally with a survey on it. Placed on the bottom of the clipboard are two shells. The person is casting a shadow on the clipboard.
Vilas County
A survey printed on a white piece of paper. What looks like a branch is on top of the paper, cover about 3/4 of the page.
Trempealeau County
In the lower right hand corner is a close up of a man with a red beard wearing a blue bucket hat and blue long sleeves. He is taking a selfie, smiling at the camera. You can see he is at the top of some stairs. At the bottom of the stairs is a person in a white jacket and blue shorts looking towards the camera, smiling. In the background is river with green foliage and rocks on the banks.
Sheboygan County
A group of people face towards the sun, posing for the photo. They are standing on a sandy shore of a lake. The lake is behind them.
Saint Croix County
A photo of a stream in the left half and purple loosestrife on the right hand side (tall green plan with purple flowrs on the top).
Rock County
Three people sit at a wooden picnic table, two on one side, one on the other. There are field guide and clipboards spread across the table. They are sitting in the shade on a sunny day.
Racine County
People stand on the left hand side of a river. The bank they are standing on is grassy and shaded. A bridge cross the river.
Ozaukee County
In the foreground is a yard sign with text. In the backgrounds is a metal statue of a catfish. The sky is blue.
Outagamie County
A person with their backed turned to the camera stands on the left side of the image. They are wearing a black jacket with sleeves rolled up and jean shorts. They are standing on the banks of a lake, with orange buckets next to them on their right. A person stands farther away in the upper right hand corner of the image. They are wearing a khaki bucket hat and red sweater. They are bent over looking at something in the water. The lake has what looks like European frog-bit.
Oneida County
A group of people stand under an outdoor awning smiling at the camera. They are backlight. It is sunny day with clouds in a blue sky.
Oconto County
Three people stand around a wooden picnic table. They are looking at field guides. Ziploc bags are on the table. Two parked cars are in the background.
Lincoln County
Three people stand posing for a photo. The person on the left has their hands in two thumbs up. The person in the middle is holding a rake head in one hand and a spool of rope in the other. The rope is attached to the rake head. The person on the right has one thumb up while the other hand holds open a field guide. The sky is a dark blue with grey/white clouds.
Kewaunee County