2026-10-30 · Daniels Lake, Boundary Waters Canoe Area Wilderness (Cook County)
Forty Tiny Cactuses in a Canoe-Only Lake — A Grand Marais Volunteer Finds Spiny Water Fleas Where No Motor Goes
Retired Minneapolis English teacher Scott Hollander borrowed a free University of Minnesota Extension net kit, paddled into canoe-only Daniels Lake in the Boundary Waters on Sept. 20, and pulled up about 40 spiny water fleas, the first new Minnesota lake found with them this year. Nobody's sure yet how they got there.
Most of us come home from a Boundary Waters trip with a sunburn on one ear, a portage bruise shaped like a canoe yoke, and a story about a moose that gets bigger every time we tell it.
Scott Hollander came home with a jar of evidence.
The retired English teacher with homework
Hollander is a retired Minneapolis English teacher who lives in Grand Marais. According to University of Minnesota Extension, he was sitting in a Minnesota Master Naturalist workshop when Amanda Weberg, Cook County’s aquatic invasive species supervisor, came in to talk about the lake testing she does around the county.
“I canoe in the Boundary Waters frequently, so I volunteered,” he told Extension. That’s it. That’s the whole recruitment pitch. Some guys see a sign-up sheet and suddenly remember a dentist appointment. Hollander saw one and raised his hand.
This also isn’t his first rodeo. He’s helped look for invasive rusty crayfish before, and he adopts a section of the Superior Hiking Trail. Honestly, my own volunteer résumé is “brought a crockpot to the church basement once,” and I’m still proud of it.
He did it properly, too. He took the AIS Detectors core course first, which is Extension’s training for volunteers who want to help spot aquatic invasive species. Then Weberg checked out a free spiny water flea net kit from the Cook County Extension office and had him practice on Devil’s Track Lake, where the critters are already known to live. Learn where you know it’s there, then go look where you hope it isn’t. That’s how a teacher plans a unit.
Sept. 20, Daniels Lake
On Sept. 20, Hollander took the kit along on a canoe trip to Daniels Lake, a roughly 500-acre lake inside the Boundary Waters. Extension says he didn’t really expect to find anything.
He found about 40 of them.
“There is no way in except by portage, and I wasn’t sure about the identification,” he said. He handed the sample to Weberg, she reported it to the DNR, and the DNR verified it.
According to Extension educator Megan Weber, who runs the AIS Detectors program, it’s the first new Minnesota lake found with spiny water fleas this year.
Here’s the weird part
Other Cook County lakes along the edge of the Boundary Waters already have spiny water fleas, and those are most likely hitchhikers that rode in on motorboats from other lakes. Daniels Lake only allows canoes.
“How did it get there?” Weberg asked. “We can guess, but it’s an important question for the researchers.”
And as a bonus mystery, some of Hollander’s samples were purple. Extension says the little things can pick up green or blue tints from algae, but purple was new. So now we’ve got a lake you can only paddle to, holding a population nobody can explain, and some of them showed up dressed for a Vikings game. Look, I can’t even explain how there’s sand in my truck in February.
Why anglers should care
A spiny water flea grows to about the size of a pinky fingernail. It’s basically a speck with a long, spiky tail. Weberg described what happens when a fish eats one: “It’s like swallowing a cactus.” She’s seen the spines sticking out of the stomachs of fish she’s filleted.
The bigger problem is what they eat. Weberg said they disrupt the base of the food chain by feeding on zooplankton that fish need to eat in order to grow, survive to maturity and reproduce. The DNR adds that they prey on native zooplankton like Daphnia, that their spines make them a lousy meal for native fish, and that they can clog the eyelets on fishing rods badly enough to keep you from landing a fish. You’d think you hooked a log. It’s actually a sweater made of tiny cactuses.
Weber also said they’re hard to find. Research suggests that in some lakes they’ve gone undetected for a decade before anybody reported them. Which means the guy with the net and the canoe matters a lot.
Want to be the next Scott?
Minnesotans can borrow a Spiny Surveillance kit free for a week. Extension says you can request one through its online form at z.umn.edu/SpinyKits or pick one up at any of 10 Extension offices: Brainerd, Cloquet, Andover (Anoka County), Bemidji (Beltrami County), Grand Marais (Cook County), Alexandria (Douglas County), Grand Rapids, Eden Prairie (Hennepin County), Park Rapids (Hubbard County) and Virginia (St. Louis County).
One rule from Sarah Waddle, the local Extension educator in Cook County: do your surveillance in teams, especially in a canoe. Don’t be a hero alone on a cold lake. Be a hero with a buddy.
And if you’re heading anywhere this fall, the DNR’s basics still apply: clean off plants and invasives, pull the drain plug and leave it out for the drive, and let docks, lifts and rafts dry at least 21 days before they go in another lake.
The part that sticks
“There is a whole series of lakes interconnected by portage that so many of us cherish,” Hollander said. “I believe we need to protect the environment. Volunteering is one way I can help do that.”
That’s a retired teacher still handing out the best lesson in the room. Nobody’s going to put a jar of 40 water fleas on a resort postcard. But somebody paddled in, dipped a net, and told the truth about what came up. Up here, that’s how you take care of a place you love.