Scientists say they don't have enough information to predict whether and how the catfish might be throwing bay ecosystems out of whack. They are only just starting to research where the bay's new catfish go to keep warm in the winter and to spawn in the spring, how much saltwater they can tolerate, and just how much their population has grown in the Chesapeake. They think recent wet years encouraged the freshwater species' spread but don't know whether that has helped their reproduction.