Now that we've gotten you an "A" on your science term paper, it's time to go fishing. First, the bad news. Because the turnover evens out the water temperature and restores oxygen to the depths, it creates habitat that was not previously hospitable to gamefish. Summer's low oxygen levels in the depths confine fish to a relatively shallow depth range above, or within, the thermocline. During the turnover, however, the fish can survive at practically any depth, so your odds of finding them have gotten longer. More bad news. Most anglers seem to think that turnover lasts only a few days and, once it's over, fishing gets back to normal. Not so, according to University of Minnesota limnology professor Dr. Robert Megard. "The turnover lasts as long as the lake is cooling," Megard says. "For all practical purposes, turnover continues until freeze-up."