Bioacoustics of Monterey Bay Pinnipeds: Auditory Fatigue and Masking.

• Main Author: Schusterman, Ronald J.
• Other Authors: CALIFORNIA UNIV SANTA CRUZ LONG MARINE LAB
• Format: Text
• Language: English
• Published: 1998
• Subjects: Biology; Acoustics; *ANIMALS; *UNDERWATER SOUND; *BIOACOUSTICS; *SEALS(MAMMALS); *AUDITORY DEFECTS; DETECTION; AIRBORNE; SENSITIVITY; SHORT RANGE(TIME); RESIDUALS; FATIGUE; CALIFORNIA; RESPONSE(BIOLOGY); LOW FREQUENCY; HARBORS; HEARING; AUDIO TONES; BAYS; ELEPHANT SEAL; MIROUNGA ANGUSTIROSTRIS; ONE HARBOR SEAL; PHOCA VITULINA; CALIFORNIA SEA LIONS.ZALOPHUS CALIFORNIANUS; Elephant Seal; harbor seal; Phoca vitulina
• Online Access: http://www.dtic.mil/docs/citations/ADA362641; http://oai.dtic.mil/oai/oai?&verb=getRecord&metadataPrefix=html&identifier=ADA362641

Auditory thresholds were obtained for one northern elephant seal (Mirounga angustirostris), one harbor seal (Phoca vitulina) and two California sea lions (Zalophus californianus) under unmasked conditions, masked conditions, and following exposure to noise. Thresholds were determined using a 50% correct detection criterion in a signal detection task using trained behavioral responses to brief pure tones. Results indicate that 1) Mirounga is most sensitive to low frequency sounds in water and is relatively hard of hearing in air; 2) Phoca has comparable auditory sensitivity to sounds of low frequency in air and under water; 3) Zalophus is more sensitive to aerial sounds than underwater sounds; 4) Zalophus is susceptible to age related hearing loss, especially at higher frequencies; 5) all three species, and Mirounga in particular, are quite good at detecting low frequency signals from noise; and 6) moderately loud underwater sounds have the potential to induce short-term residual hearing loss in all species tested.