BRS Socal proposal

The project is part of a multi-institutional multi-year research program designed to measure responses of marine mammals to naval sounds with a focus on measuring the exposure linked to onset of behavioral disruption. This research will involve integrated use of: opportunistic monitoring of animal populations using sightings and detection of vocalizations, and acoustic tagging for more detailed but shorter term exposure and response data. The results are likely to provide critical input for regulatory decision-making for agencies and navy by elaborating acoustic criteria such as those presented in (Southall et al., 2008).

The project focuses on describing behavioral responses of different taxonomic groupings of cetaceans and quantifying the exposures to sonar that lead to significant disruption of behavior. The overall objective is to provide a better scientific basis for estimating risk and minimizing effects of active sonar for the U.S. Navy and regulatory agencies.

This project balanced a focus on tagging difficult but high priority species such as Cuvier's beaked whale with working with other species when necessary. This combination was very successful with 56 blue whales tagged and controlled exposure experiments conducted on 17. Exposure to sonar caused significant disruption of foraging behavior, but traveling whales appeared to be less sensitive. The first two controlled exposure experiments were conducted with Cuvier's beaked whales tagged with acoustic and movement recording tags. These beaked whales showed strong and sustained avoidance responses to sound exposure levels well below the current thresholds for response used by regulators. In addition reasonable sample sizes were built up for several other species, enabling papers at a later date when the sample sizes are increased.