North Temperate Lakes

People are powerful agents of landscape change, and some of our most dramatic effects come through transplanting species to new ecosystems. Native plants and animals are seldom adapted to coexist with non-natives. The first person who released a rusty crayfish (a great fishing bait native to the Ohio valley) in a northern Wisconsin lake probably figured this was a brilliant idea…but it opened a Pandora’s Box. Rusty crayfish mow down aquatic plants, which are critical cover and feeding areas for young fishes, leaving a barren bottom with no shelter and little food.

Signs at most boat landings alert boaters to the danger of moving invasive animals and plants between lakes. Some invaders travel in bilge water or minnow buckets that are dumped into a lake. Plants like Eurasian watermilfoil travel on boat trailers and motors. Unfortunately, once they enter, invasives can be difficult or impossible to eliminate; the best way to avoid opening another Pandora ’s Box is to halt the movement of species between lakes.