Yep ... the little buggers breed like nobody's business, and being nonnative, nothing here eats them. They clog water intakes, cover boat hulls, and in some areas they actually filter the water too much, leaving no nutrients for native species. There are workarounds for some of this, but they're a mixed blessing. Or a mixed curse. I suppose it's a matter of perspective.
Apparently they make the water too clean for native species. How bizarre.