Behavioral response of leatherback sea turtles to impulsive sounds
 

Project leads: Samir Patel and Liese Siemann

Funded by: The Bureau of Ocean Energy Management

Sea turtle responses to acute stimuli, particularly while in water, have not been well studied. Researchers have only recently developed techniques to fully understand the scope of sea turtle hearing while underwater. It is unclear why sea turtles evolved their characteristic hearing capacity, specifically in the low frequency ranges where their hearing is sensitive, because limited work has been done to measure the response of sea turtles to sound in their natural environment.

 

Recently, CFF tested several short term tags placed on sea turtles to record footage from the perspective of the animal, along with GPS locations, turtle movement patterns and other environmental variables, including sound. CFF tested these camera tags on leatherback turtles in Massachusetts and North Carolina state waters in collaboration with scientists from NMFS. We accrued approximately 35 hours of footage from 23 leatherback turtles. For several deployments, we used AMX tags designed by Loggerhead Instruments that record high resolution video footage, temperature, depth and GPS location and include an accelerometer, hydrophone, burn-wire release system, and a transmitting beacon for at-sea recovery. For this project, AMX tags will be affixed to leatherbacks using suction cups, and the turtles will be exposed to impulsive sounds from a sparker (used for geophysical surveys). Acoustic exposure data will be collected by the tag hydrophones, and turtle behavior will be correlated with sound exposures to better understand the likely impacts of offshore wind development on sea turtle behaviors.

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Leatherback sea turtle audiogram and overlap of turtle peak hearing frequencies with impulsive sounds from geophysical survey equipment used in offshore wind farm construction.