Temporary threshold shift in a harbor seal (Phoca vitulina)

During in-air auditory threshold testing, a harbor seal was inadvertently exposed to broadband construction noise for 6 days, averaging 6 to 7 h of intermittent exposure per day. When tested immediately upon cessation of the noise, a temporary threshold shift (TTS) of 8 dB at 100 Hz was evident. In addition, the animal's false alarm rate increased from 7% in the pre-exposure session to 30% in the post-exposure test session. Following 1 week of recovery, the subject's threshold was within 2 dB of its original level, and the false alarm rate was less than 10%. The data suggest that TTS can be induced in seals, and that our subject may have suffered from tinnitus, resulting in a reduced ability to distinguish signal-present from signal-absent trials. (C) 1996 Acoustical Society of America.