Sound source localization by the plainfin midshipman fish (Porichthys notatus).

Abstract

Sound source localization of the midshipman fish (Porichthys notatus) was studied using the phonotactic response of gravid females to synthetic advertisement calls. Playback experiments were conducted in a 12‐ft‐diameter outdoor concrete tank at the Bodega Marine Laboratory using a J‐9 transducer placed at the center of the tank. The sound field in the tank was measured at 5‐cm intervals using an eight‐hydrophone array to measure the pressure gradients from which particle motion vectors were calculated. The acoustic measurements confirmed that the J‐9 projector was operating as a monopole source. Animals were released 90 cm away from the sound source, and 60 positive phonotactic responses from naïve gravid females were video taped and analyzed. The phonotactic responses consisted primarily of straight to somewhat curved tracks to the sound source. Abrupt changes in trajectory to the sound source were rarely observed. The results confirm that fish can locate sound sources in the near field.