It has been suggested that most teleost fishes cannot detect sounds higher than 2 or 3 kHz (ref. 1). However, we report here that at least one species of clupeid fish (herrings and shads), the American shad (Alosa sapidissima), can detect sounds up to 180 kHz. We speculate that clupeids are able to detect the ultrasonic clicks of one of their major predators, echolocating cetaceans2.