Insights into the underwater behavior, species interactions, and biomechanics of baleen whales using integrated video and inertial sensors
Goldbogen, J, D Cade, J Calambokidis, A Stimpert, M Jensen, J Potvin, and A Friedlaender. 2015. Insights into the underwater behavior, species interactions, and biomechanics of baleen whales using integrated video and inertial sensors. Abstract (Proceedings) 21st Biennial Conference on the Biology of Marine Mammals, San Francisco, California, December 14-18, 2015.
Bio-logging approaches to study the biology of free-ranging animals often focus on audio, movement, or video, but rarely are these different data streams integrated. Here we custom engineered a tag to measure the fine-scale kinematics of cetaceans while simultaneously recording animal-borne video from dual cameras. The movement sensors included a pressure transducer, tri-axial inertial sensors (accelerometers, magnetometers, gyroscopes), and a paddle-wheel speed sensor. The cameras were pointed anteriorly 45 degrees to the right and left of the long axis of the tag, together generating a 180-degree view in the horizontal plane. We deployed these tags on 5 blue whales and 8 humpback whales off the coast of California during the summer of 2014, and 2 gray whales off the coast of Washington in April 2015. For the first time, we observed a wide-range of behaviors of the tagged whale, conspecifics, and parasites. These included interactions between whale lice, aggregations of prey (krill, anchovies) and non-prey (siphonophores) species that the whales encountered, remora swimming and attachment behavior, echelon swimming formations with other whales, and feeding with other whales and sea lions. During some deployments we were able to observe how the movements of flippers and flukes are involved in facilitating different maneuvers including lunge feeding. For example, when the tags were pointed perpendicularly to the long axis of the whale's body, we could detect simultaneous movement of flipper and fluke, highlighting the fine-scale body control and varied use of different propulsion and control surfaces. By combining video and kinematic data, this tag design serves as an important tool for understanding the biomechanics and behavioral ecology of large aquatic vertebrates.