Rusty crayfish disappearing from some northern Wisconsin lakes — and that’s a good thing

Many of the lakes have seen steady declines of the crustacean, with a handful of lakes falling to nearly zero. Szydlowski, who is now working on a PhD in freshwater and marine science at UW-Madison’s Center for Limnology, said that the declines could be caused by a fungal disease and by crayfish destroying their own habitat.