As a kid, I used to hunt crayfish ("zarigani" in Japanese) in the creek near my house with my friend, whose mother was coincidentally Cajun, so she'd cook them up for us and we'd feast. But they burrow, and I guess that is the problem with their invasiveness of Lake Ezuko: they weaken its banks. So Kumamoto has begun a program to eradicate the species - likely much to the sorrow of the kids who enjoyed capturing them.