Southern Crawfish Are the Newest Scourge to Northern Infrastructure

Wildlife authorities in Michigan received the two reports just days apart in July, one from a lake near Vicksburg and another 100 miles away in a retention pond outside of Detroit. Both tips concerned the same critters—red swamp crawfish, or Procambarus clarkii, pint-sized crustaceans with a bloodletting pinch native to Southern states like Louisiana.

When state workers visited the Detroit-adjacent pond in Novi, they found the land around the water shot through with what looked like cannon fire. “You wouldn’t be able to walk through without probably sinking your shoes in,” says Michelle Crook, a senior project engineer for Michigan’s Department of Natural Resources. “On better than half of the pond, I’d say there’s probably a two-foot width of the shoreline where there are chunks with holes and areas falling in.”