By Dr. Holly Fearnbach, Marine Mammal Research Director
SR3’s Dr. Holly Fearnbach collaborated with researchers from Southall Environmental Associates, Cascadia Research Collective, University of California Santa Cruz and Kelp Marine Research on a paper Behavioural responses of common dolphins to naval sonar recently published in the scientific journal Royal Society Open Science. This project used a novel integration of research methods including photogrammetry of aerial drone imagery, acoustic monitoring using underwater listening recorders, and tracking using shore-based theodolite to assess the impact of Navy sonar on dolphin populations off of Santa Catalina Island, California. The team found clear evidence of responses by the dolphins to sonar, including acoustic responses and behavioral changes such as changes in direction, speed and group configuration. The results show that the dolphins responded to sonar at much lower sound levels than previously considered in regulatory decisions warranting important management considerations. Read more here.
Images collected during a study on the behavioral response of common dolphins to Navy sonar off Catalina Island, California: Left (top and bottom): Dr. John Durban flying the drone into the hands of Dr. Holly Fearnbach following a flight over common dolphins. Top right: Photo of a long-beaked common dolphin surfacing; Bottom right: Aerial image of a group of short-beaked common dolphins. Aerial image collected during a high-altitude (>200 ft) drone flight. Research authorized by NMFS research permit # 19091.