Our canoe rocks in Sammamish’s 85-acre Pine Lake, crowded by a park and dozens of lake houses with docks and man-made beaches. Midsummer, hordes would be out to splash and set nonmotorized boats adrift here, but in September, our only company is a swimmer tugging a yellow buoy. Olden positions the crayfish (“crawfish” is also acceptable, he says) inside metal calipers, from the equivalent of her nose to the base of her ribcage, and gives a gentle squeeze.

“It's right on 63 — I'm not lying,” he says with a laugh, eyes crinkling at the corners. “That's pretty good. I don't need calipers anymore. Calipers out the window!” He logs other measurements, sex, location and a few notes before plopping her back into the water.

Olden monitors changing populations of invasive to native signal crayfish in an effort to document environmental changes. (Hannah Weinberger/Crosscut)

It’s not surprising that Olden’s dimensional sense for crayfish is dialed in. A professor at the University of Washington's School of Aquatic and Fishery Sciences, Olden has floated Pine Lake four times each summer for 12 years to study them, and we’re out doing his final sampling of 2019. But it’s jolting to see him return her to the lake: Red swamps, the pride of Louisiana crayfish boils, are invasive in this lake. She’s not supposed to be anywhere in Washington, period. But she’s an unwitting accomplice in Olden’s effort to evaluate invasive species management in a changed lake.

To monitor changing population dynamics of invasive to native signal crayfish, he sets 40 traps full of large-breed dog food around the lake perimeter on summer weekends, sometimes with his daughter. Olden then analyzes and releases, rather than removes, animals unlucky enough to crawl into them, so he can evaluate the ecosystem’s natural responses to invasion.

It’s humble research, repetitive by design. There’s no dedicated funding. But to Olden, it’s a proving ground for a looming ecological disaster, and he’s the only researcher behind enemy lines. He’s sampled a couple hundred Western Washington lakes, but Pine Lake has historic importance: The state’s first red swamps were found here in 2000, and they’ve since spread to about a dozen other bodies of water in the state. So far, he’s shown that signals and red swamps tensely coexist in Pine Lake, with human intervention; he spent a few years removing red swamps to gauge management impacts. But in many invasions, native crayfish disappear completely.