Photo credit: Instigator/Shanna Stawicki Photography
Two recent studies confirm that sea turtles not only hear underwater sound, but that human-generated noise can significantly disrupt their behavior—interfering with feeding, navigation, and other critical life functions.
A study published in the Journal of the Acoustical Society of America, “Underwater Hearing Sensitivity of the Kemp’s Ridley Sea Turtle”, examined the critically endangered Kemp’s ridley sea turtle using juvenile turtles in a lab setting. Kemp’s ridleys inhabit nearshore and continental shelf waters of the Gulf of Mexico and the western North Atlantic—areas with intense human activity. They nest primarily in Mexico, but also in Texas and other Gulf states, and migrate as far north as New England and Canada to forage in shallow, nutrient-rich waters on crabs, other crustaceans and fish.
Researchers from Duke University Marine Laboratory, National Oceanic and Atmospheric Administration, and North Carolina State University found that Kemp’s ridleys are particularly sensitive to low-frequency sound waves—the same frequencies produced by ships, seismic airguns, and other noise pollution associated offshore energy development. Because low-frequency noise travels long distances underwater, it can mask sounds turtles rely on for orientation and communication, potentially hindering their recovery.
A second study, “Leatherback Sea Turtles (Dermochelys coriacea) React to Impulsive Sounds,” published in Scientific Reports, examined how endangered leatherback sea turtles respond to impulsive sounds—sudden, intense bursts of noise associated with offshore construction, including oil and gas platforms and wind turbines. Impulsive noise increases sound pressure rapidly across a broad range of frequencies and can be more damaging than continuous noise.
Leatherbacks—the largest sea turtles, reaching up to 2,000 pounds and nine feet in length—are uniquely warm blooede (endothermic), allowing them to forage in cold waters such as those off New England and Canada. Despite their massive size, they subsist on jellyfish and other soft-bodied prey that are 95–98% water, requiring them to consume extraordinary quantities—up to 73% of their body weight daily, having to eat as much as 2,000 pounds of jellyfish, tunicates, and other soft-bodied prey in a single day.
Any disruption to feeding can have serious consequences.
In the Massachusetts study area, researchers tagged foraging leatherbacks with video, acoustic, depth, and temperature recorders. The results were striking: exposure to impulsive noise was associated with up to a 64% decrease in the probability of foraging.
As offshore energy development expands in the Atlantic and other coastal areas, understanding and mitigating underwater noise will be essential to protecting endangered sea turtles and ensuring their
