This story is part 1 of a 3-part series. Read about how we are listening for North Atlantic right whales with passive acoustics, monitoring them with aerial surveys, and using boats, drones, uncrewed surface vehicles and satellites to learn as much as we can about them and their habitat. In the Northeast, we work with many partners to track right whales, including mothers and calves, using advanced technology to help inform actions that reduce risks to the species.
Endangered North Atlantic right whales had a busy winter! NOAA Fisheries and our partners saw 23 right whale mom and calf pairs during the right whale calving season in the Southeast. This is hopeful news for the species. With only 380 North Atlantic right whales remaining, including about 70 reproductively active females, each mother and calf is vital to the species’ recovery. Human impacts continue to threaten the survival of the species.
Reducing risk to these whales is a top priority as they spend the summer in their northern feeding grounds, and technology is helping us do it. With our partners, NOAA Fisheries is monitoring right whales using cutting-edge techniques like real-time passive acoustic monitoring and measuring calf growth rates with drones.
The data we collect inform management and conservation measures that reduce the risks whales face from human impacts, including vessel strikes and entanglements. Our continuous monitoring supports coexistence between marine industries and right whales.
Listening for Whales with Passive Acoustics
(Link to audio: North Atlantic right whale upcall)
The Northeast Fisheries Science Center uses passive acoustics to monitor the New England and Mid-Atlantic waters for right whales 365 days a year. Scientists identify the calls that right whales use to communicate with each other, alerting them to their presence. Real-time passive acoustic technologies, including moored surface buoys and autonomous gliders, can detect right whales almost instantaneously.
These data allow us to reduce the risk of potential interactions with vessels using voluntary Right Whale Slow Zones. Like driving through a school zone, slow zones urge mariners to avoid these areas or slow down to 10 knots or less to prevent lethal collisions with whales.
Real-Time Passive Acoustic Monitoring Network
We support a near real-time passive acoustic monitoring network up and down the East Coast. Near real-time data are available soon after the initial collection. The network is designed to allow scientists to listen for right whales along their migration route. This large-scale, collaborative effort includes the Woods Hole Oceanographic Institution, state agencies, universities, the U.S. Navy, and private industry.
Moored Surface Buoys
Several real-time moored surface buoys detected right whales during their migration this spring. For example, a moored surface buoy off of Martha’s Vineyard deployed on March 20 acoustically detected right whales on 15 separate days during its first month in the water.
Cape Cod Bay is a critical right whale habitat. Our collaborators at the Massachusetts Division of Marine Fisheries support a moored surface buoy to immediately detect right whales as they enter and move through the Bay. This season, the buoy detected right whales on most days from November 20, 2025, until May 4, 2026, when they migrated out of the area. Last year, we consistently heard right whales in Cape Cod Bay from buoy deployment in February until May 2025. This data shows right whales are present throughout the winter as well as in the spring.
Slocum Gliders
To monitor the right whales that stay in the Northeast for the winter, we worked with the Woods Hole Oceanographic Institution to deploy a Slocum G3 glider in the Gulf of Maine last fall. It traveled more than 1,500 miles “listening” for whales in real-time from October 2025 through February 2026.
Archival Data: Understanding Migration Patterns
Along with many partners, we also collect archival data, which is available to scientists much later in time than initial collection. We use hydrophones, or underwater microphones, anchored to the seafloor. More than 50 of these devices are deployed in the Northeast and Mid-Atlantic. They can be deployed for up to 5 months to continuously record whale sounds. They capture not just whale calls, but also fish and invertebrates, boat noise, and other human activities.
These data provide a long-term acoustic record that helps us study whale migration patterns and evaluate behavior and changes in distribution over time. For example, in 2023, our hydrophones detected right whales in Southern New England on 196 separate days.
Advantages and Limitations of Passive Acoustic Technology
Passive acoustic technology is non-invasive, and we can hear whales in some areas where we cannot see them at the surface. It is particularly useful at night and in challenging weather conditions, when aerial surveys cannot operate. While right whale moms and calves tend to be quiet, mostly communicating with each other, this technology can help identify them if they are near other whales that are vocalizing.
Sound cannot be used to identify individual right whales. This is why we use passive acoustic monitoring in tandem with aerial and ship-based surveys. Acoustic detections can direct those survey teams to monitor areas where right whales have recently been heard.
We are working with our partners to improve how we share and compare acoustic data. Strengthening this infrastructure helps paint a more complete picture of whale migration and behavior. You can see all of the passive acoustic detections of right whales, and the organizations involved in data collection and analysis, on the Passive Acoustic Cetacean Map.
Listening to Right Whales with Help From Partners
Partners collecting real-time acoustic data to help monitor whales in the Northeast include:
- Woods Hole Oceanographic Institution
- Massachusetts Division of Marine Fisheries
- Maine Department of Marine Resources
- U.S. Navy (NAVFAC Atlantic)
- University of Maryland Center for Environmental Science
- Wildlife Conservation Society
- Stony Brook University
- Rutgers University
- Skidaway Institute of Oceanography
- University of Maine
- University of South Carolina
- University of New Brunswick
Stay tuned for part two of this three-part series, monitoring right whales from above with aerial surveys.
