Crystal Lake: Are Invasive Smelt on Their Way Out?

Team members move a GELI (attached to a red air hose) into the water so it can be towed to its spot in Crystal Lake by boat.

Back in 2009, a team of engineers and scientists affiliated with the Center for Limnology had a crazy idea – they wanted to see if they could manipulate an entire lake to kill off an invasive fish without harming the lake’s native fish. (The usual method for eradicating an invasive species is poisoning the entire lake, killing everything, and then re-stocking it with native fish).
Team members attach the rubber air bladder to the metal frame of the GELI.

The group spent a summer up at Trout Lake Station and built from scratch a contraption that looked like a giant trampoline. It was a rubber air bladder stretched around a metal frame and attached to an air hose. They called it a gradual entrainment lake inverter, or GELI, for short. Four summers later, their experiment may be paying off. The smelt in Crystal Lake are acting very strange without the cold bottom layer of water they used to enjoy. Perhaps this will be the summer of their discontent….
Read more about the Mixing Project from the UW-Madison College of Letters and Science online newsletter.
Zach Lawson displays a rainbow smelt, target of the group’s ambitious eradication effort.

Without any context, Zach Lawson’s current endeavor seems downright morbid.
Lawson has spent the past two and a half years working on a project that, should things go according to plan, will kill thousands upon thousands of fish in a northern Wisconsin lake.
“The idea is to extirpate the entire population,” he said.
Read the full story at the College of Letters & Science “News and Notes” page.
Or watch Zach discuss the latest update from the shores of Crystal Lake:

And, for a longer history of the entire mixing project, you can watch this:

Finally, a few shots of gulls picking agitated smelt off the surface of Crystal Lake. (Normally during the hot summer days, adult smelt congregate in the cold deeper waters of the lake).