I tell my kids,” says Tom Conrad, “that when smelt are running, it’s a signal of spring, when everything wakes up after winter.” And those kids were in for a show last March, when Conrad and his partner, photographer Carrie Marie Burr, brought them to a brook near their home in Huletts Landing, on Lake George. That day, says Conrad, the coltsfoot was blooming—a sign for smelt spawning time, according to local lore—and the kids witnessed a narrow Lake George tributary thick with dark, torpedo-shaped fish. The boys learned not to disturb the brook’s sandy beds where the fishes’ eggs had been laid, and that up to four weeks later the young would hatch and drift back into the lake. It was a teachable moment. Living in the Adirondacks means…