Evasive responses of American shad (Alosa sapidissima) to ultrasonic stimuli

Many species of odontocete cetaceans (toothed whales) use high frequency clicks (60–170 kHz) to identify objects in their environment, including potential prey. Behavior and physiological studies have shown that American shad, Alosa sapidissima, can detect ultrasonic signals to at least 180 kHz. This study demonstrates that freely swimming, American shad show a variety of behaviors in response to pure tone, ultrasonic stimulation. This response depends primarily on stimulus amplitude and, to a lesser degree, on stimulus frequency, direction and duration.