In the vast, blue expanse of the U.S. South Atlantic, a mystery unfolds every year. The North Atlantic right whale, one of the world's most endangered large whales, embarks on a long journey from northern feeding grounds to southern calving waters. But how do you discover the movement patterns of a giant that spends most of its life hidden beneath the waves?
Meet the SoundTrap—the underwater audio recording device that’s changing the game for monitoring whales. SoundTraps are passive acoustic monitoring devices built for long-term, continuous archival recording. They’re typically deployed by NOAA Fisheries scientists for 6-months at a time. Later, scientists retrieve these units to analyze the vast amount of underwater audio captured during their time on the seafloor—including sounds from vocalizing animals.
Monitoring Right Whale Movements
Monitoring the North Atlantic right whale isn't just about curiosity; it’s a science-based strategy for supporting the conservation of a species with approximately 380 individuals remaining. We use the best available science to inform management decisions.
We monitor the movements of right whales in the Southeast United States because this region serves as the species' only known calving grounds. It’s not just the mom-calf pairs that are seen here; nearly a quarter of the existing population can be found in the South Atlantic during the winter and spring months. NOAA Fisheries scientists use passive acoustic monitoring to detect these whales in their calving grounds, and to monitor and understand shifts in their migration patterns. Acoustic detections recovered from passive acoustic technologies like SoundTraps can help scientists identify new migratory patterns and understand where specific whales were at specific dates and times. This helps us promote a sustainable coexistence between thriving marine industries and North Atlantic right whales.
Beyond distribution monitoring, these acoustic data are a goldmine for understanding habitat use, behaviors, and vocal variation. This is important so we can identify key behavioral patterns that allow us to take an active approach in species conservation. These data also give insights into how whales interact with human-made threats like vessel traffic.
From Sound Waves to Migratory Maps
By acting as the "ears" of the ocean, SoundTraps provide a continuous, high-fidelity window into the movements of the North Atlantic right whale. We strategically deploy SoundTraps throughout the entire southern region of the species’ range. For the 2026 right whale calving season, we placed SoundTraps from Hatteras, North Carolina, all the way down to Cape Canaveral, Florida. All of this work is conducted from a small boat that is trailered up and down the Southeast.
Once we retrieve these recorders, scientists use the Low Frequency Detection Classification System, a specialized detector. It sifts through months of audio to pinpoint upcalls, the signature vocalizations used by North Atlantic right whales of all ages.
Experienced analysts then verify these acoustic detections, transforming raw sound into a detailed map. By identifying patterns in the data, researchers can monitor exactly when right whales are moving south to calve or north to feed, revealing how these cycles shift annually or over decades.
Efficiency of 24/7 Underwater Monitoring
Researchers have historically relied solely on aerial surveys and vessel-based operations for real-time monitoring and mitigation, photo identification, and genetic sampling. The advent of long-term acoustic recorders has revolutionized how we monitor habitat use of these endangered giants. Long-term, continuous recorders allow for acoustic monitoring 24 hours a day, 7 days a week, for extended periods of time and in all sorts of weather. This level of monitoring isn’t feasible for human researchers. The use of passive acoustic technologies reduces limitations such as daylight, visibility, good weather conditions, and personnel requirements.
Complementing aerial and vessel monitoring with advanced technologies like SoundTraps allows scientists to form a clear and often continuous, after-the-fact, picture of species behavior in the absence of any visual observations.
While acoustic monitoring is still subject to challenges like vocalization rates and background noise from shipping traffic, it offers a remarkably continuous and reusable monitoring platform. Perhaps most importantly, the raw data captured serve as a permanent archive. This allows future generations of scientists to revisit and analyze these underwater recordings for decades to come.
As the sun sets over the Southeast coast, the SoundTraps remain active, silently documenting the movements of North Atlantic right whales. Each retrieval brings us closer to understanding the shifting rhythms of the species, providing the evidence-based roadmap needed to aid species conservation.
More Information
Learn more about how you can help right whales. Remember to report all right whale sightings from North Carolina to Florida to (877) WHALE-HELP/(877) 942-5343, and from Maine to Virginia to (866) 755-6622.
See where right whales have been spotted near you by visiting our interactive WhaleMap.
