Mechanisms for directional hearing in the sea catfish (Arius felis).

The marine catfish (Arius felis) uses directional hearing for the acoustical detection of obstacles, and is primarily dependent on the vector components of near-field acoustics. Directional sound, detected as lateral line action potentials, produces the strongest response on the side toward the stimulus. Responses are maximal in the 50-150 Hz range. The swim bladder is asymmetrical as a sound generator (7 dB front-to-back ratio). As a sound receiver, the swim bladder is even more directional (24 dB front-to-back ratio at 100 Hz). It is concluded that directional response to sound in fishes can involve the interaction of at least two mechanisms, in this case the lateral line and the swim bladder.