Improving the Utility of the CATs Video Cam and Tri-axial Accelerometer for Examining Foraging in Top Marine Predators
Hopkins Marine Station, Stanford University Pacific Grove United States
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This project is aimed at improving the use of video accelerometry tags for understanding animal location, movements and foraging behaviors. The project aim is to test the second generation of CATS camera tags, a state-of-the-art archival inertial measurement tag with HD video and satellite for measurements of foraging and swimming performance in marine vertebrates. The CATS units are capable of recording motion with 9-degrees of freedom at high temporal resolution. Tri-axial accelerometers, magnetometers and gyroscopes record motion at 100 Hz for durations, depending upon how programmed for up to a week. In addition to the inertial measurement unit, the packages include a high resolution pressure-sensor depth and a speed sensor, based on a rotating turbine wheel. 18 hours of video can be recorded simultaneously with a duty cycle spread throughout the daily diary package data record. As these units collect large volumes of data no current technology is able to relay it via telemetry to satellite, and it is necessary to physically recover the units. These units will incorporate a pop-off-mechanism, whereby a galvanic release will activate after a set duration 1-3 days upon which they will float to the surface and transmit their location via the Argos satellite. Units will be recovered at sea via boat. Testing of attachment strategies and performance will be conducted in the California Current in Monterey Bay and in laboratory settings. Our main goal will be to characterize the foraging performance of top marine predators in combination with inertial measurement units coupled with HD video.