Every summer, Minnesotans slide their boats into quiet morning waters and toss their lines into deep waters in hopes of catching walleye, bass, or northern pike. They might see a heron, beaver, or loon to say hello to along the way. And while a $113 billion industry relies on recreation each year in the U.S. Midwest, those lakes and those walleye are changing. They are responding to shifts in air and water temperature, precipitation, and seasonality, in ways that we do not yet understand.