Behavioral reactions of dolphins and sea lions to sonarlike sound exposures.

Colleagues Ron Schusterman and Dave Kastak were instrumental in the advancement of marine mammal cognition and sensory biology studies. In the past 2 decades, their work was heavily concerned with the potential impact of anthropogenic sound on pinnipeds. Behavioral reactions of marine mammals to anthropogenic sound exposure are one impact with a large range of potential consequences. Recently, 30 dolphins and 15 sea lions were exposed to sonarlike pings used in antisubmarine warfare. Exposures occurred while animals performed a behavior in which they traveled from one location to a second where they touched a paddle, and then returned for a food reward at the starting location. Subjects performed a ten trial baseline session followed by a ten trial experimental session in which sound exposures occurred. Each subject was randomly assigned a receive level from near ambient to 185 dB sound pressure level. For each subject, received levels were consistent across all experimental trials. Behavioral reactions were anticipated prior to the study and assigned a severity score by a panel of anonymous reviewers. Scores were used to explore relationships between the received level and the severity of the behavioral response.