A University of South Carolina researcher hopes to save endangered right whales by listening for them.
Less than 350 North Atlantic right whales remain in the wild, scientists estimate, and ship strikes are one of the most pressing hazards that threaten the whales. This danger is especially high when their winter migrations bring them near busy ports in Charleston, South Carolina, and Savannah, Georgia.
Erin Meyer-Gutbrod, a research professor in the School of the Earth, Ocean and Environment, has been studying the critically endangered species for over a decade. She tracks migratory patterns off South Carolina’s coast to understand why the whales have seen such dramatic population declines.
Her current research is a collaborative effort with researchers from the University of Georgia Skidaway Institute of Oceanography. The researchers have deployed underwater listening robots to locate migrating whales and alert ships that may be in the area.
Whales are detected using gliders, torpedo-shaped underwater vehicles fitted with recording devices called hydrophones. Because the gliders move through the water by adjusting their buoyancy instead of using traditional motors and propellers, they make very little sound, making them ideal for the mission.
Equipped with satellite phones, the gliders surface periodically to transmit data to base stations on land. Meyer-Gutbrod and her team compare the glider-collected acoustic data with archival acoustic data collected with bottom-mounted hydrophones to assess the glider's detection capabilities.
“Passive acoustic monitoring is a really valuable tool for monitoring baleen whales, such as right whales, because it is often less expensive than visual observations, and data can be collected 24/7 and in bad weather,” Meyer-Gutbrod says.
The gliders will be complemented by three stationary hydrophone moorings which will also listen for whale vocalizations. The researchers will be able to compare what is heard by each of the instruments.
“I will compare the glider-collected acoustic data with archival acoustic data collected with bottom-mounted hydrophones to assess the glider's detection capabilities in this environment,” Meyer-Gutbrod said.
The project is not only about picking up whale vocalizations, but researchers will also use a low-frequency detection and classification system developed at Woods Hole Oceanographic Institution to identify the species of baleen whale that made the sounds.
The detections will be communicated to ship captains by the management and conservation apps Whale Alert and Whale Map, and the researchers hope that information on verified whale detections will encourage ships to take protective action, such as slowing down to less than 10 knots.
The project also hopes to answer other research questions about this technique, such as how shallow the gliders need to get to hear the whales, how much background noise is heard from the environment and how much noise from the glider itself interferes with the ability to hear whale calls. Additionally, researchers want to study recent changes in whale migration patterns.