In California’s national marine sanctuaries, scientists are tuning in to the surprising and often overlooked sounds fish make. Many fish species communicate via hums, grunts and drums that they produce by vibrating their swim bladders or rubbing bony parts together. “For example, acoustic monitoring helps us learn which fish species are present, when they spawn, and which sanctuary habitats are important to them. Their year-round chorusing at a site in the southernmost portion of Monterey Bay National Marine Sanctuary suggests this is likely a key mating ground. The Office of National Marine Sanctuaries has developed lesson plans in a new educational toolkit for elementary and middle school students to learn how marine animals communicate.