The 2013 field season of the 5-year Southern California Behavioral Response study is underway now. This research applies suction-cup tags to whales, which track the whales’ movements (dive patterns, speed, direction, etc.) while also recording the sounds the whales are hearing, including sounds of mid-frequency active sonar played underwater by the researchers under carefully controlled conditions. Earlier years’ results have begun to quantify the level of sound that can spur behavioral reactions in several species of whales, including the beaked whales that have appeared to be more sensitive to sonar sound, resulting in several stranding incidents over the past fifteen years. Most recently, two new papers reported that both blue whales and Cuvier’s beaked whales seem to avoid sonar sounds, and at times stop feeding, at sound levels below most current regulatory thresholds.
SOCAL researchers will be posting updates from the field here.