For the past 3 years, our Habitat Camera (HabCam) Survey has had self-propelled underwater helpers. From June 30 to July 6 of this year, two Tethys-class long-range autonomous underwater vehicles, or LRAUVs, surveyed more than 200 nautical miles of pre-programmed track lines in the Mid-Atlantic. Together, they captured more than 68,000 images of the seafloor, collecting critical data used in fisheries stock assessments.
LRAUVs provide an alternative way to survey areas of the ocean where traditional research vessels cannot go because of offshore development. The data they collect complements our vessel-based HabCam Survey, which collects millions of seafloor images each year to understand Atlantic sea scallop populations.
Technology Strengthens the Sea Scallop Assessment
Our scientists identified sea scallops, fish, crabs, snake eels, squid, skates, and more in the seafloor images taken by LRAUVs this year. They will present these data, along with HabCam Survey data, to the New England Fishery Management Council at the end of August. The Council’s Scallop Plan Development Team will incorporate the data into the Atlantic sea scallop assessment. Ultimately, the data help generate more accurate estimates of sea scallop abundance and distribution to inform management decisions.
Advanced Technology Specialist Cameron Fairclough notes that this technology expands where and when we can collect data. "This autonomous underwater vehicle can image the seafloor and you can control it from your phone while it’s out in the middle of the ocean," he explained.
A Flexible Platform for Research
This LRAUV was designed by the Monterey Bay Aquarium Research Institute. Woods Hole Oceanographic Institution (WHOI) owns and operates the two vehicles we currently use, named Stella and Polaris. It is a flexible platform that can support many different survey methods. It has standard sensors to collect general oceanographic data including temperature, salinity, dissolved oxygen, phytoplankton concentration, and information about ocean currents. Scientists build on additional sensors to support their diverse oceanographic data collection needs. All of the sensors are housed in the nose of the torpedo-shaped vehicle. Along with LED lights to illuminate the seafloor, LRAUVs can carry specialized sensors for HabCam Surveys including:
- Stereo cameras to photograph and measure sea scallops
- CTD instrumentation to understand the seafloor environment
- ECO triplet optical sensor that collects more detailed phytoplankton concentration and water clarity data
You’re Not Going to Need a Bigger Boat
At approximately 9 feet long, 12 inches in diameter, and 250 pounds, the LRAUV can be deployed over the side of a small boat, reducing the cost of deployment. It is a hybrid vehicle that combines the long battery life of a glider with the power capabilities of a propeller-driven AUV, allowing it to power more sensors. On a HabCam mission, the LRAUV’s standard rechargeable lithium batteries can last for about a week.
LRAUVs can dive up to 984 feet. It controls its buoyancy and position in the water by shifting its internal battery weight to tilt its nose up or down and using a buoyancy engine to pump mineral oil inside or outside of its pressure housing. It drives itself through the water using a combination of a thruster, elevator, and rudder fins. Its average velocity is about 2 nautical miles per hour, or one knot, and its range is more than 600 miles. It navigates underwater using its compass and doppler velocity logger.
Why We Started Using a Long Range Autonomous Underwater Vehicle
Our use of LRAUV technology grew through a collaboration between our science center and WHOI’s Deep Submergence Lab. The team began developing the camera technology for the LRAUV platform in 2021. WHOI led the engineering and development of the LRAUVs camera systems, which use the same camera system as HabCam. This allows the imaging data they collect to complement the data collected during the survey. Our goal was to develop a benthic imaging AUV for sea scallop surveys that could:
- Collect data for long periods
- Be deployed and retrieved from various platforms
- Survey areas of the ocean where our research vessels could not safely operate, including wind farms and other offshore energy platforms
The camera development and testing were funded by NOAA's Uncrewed Systems Operations Center. Other aspects of the project are supported by the Northeast Fisheries Science Center.
After the first camera system was built, we worked with WHOI to equip a LRAUV with the system and completed test surveys in 2023.
After years of developing and testing, the team compared 2024 LRAUV data with overlapping data collected by our Scallop Dredge and HabCam Surveys. We presented our findings to the New England Fisheries Management Council’s Plan Development Team. Following their technical review, LRAUV data was incorporated into annual sea scallop abundance estimates to support management decisions.
That winter, we successfully deployed the LRAUV from a 25-foot boat in Buzzards Bay, Massachusetts. It completed research tracks within and around the South Fork Wind Farm, about 35 miles east of Montauk, New York. It collected data that would otherwise not be possible to get.
Our use of the LRAUV has grown steadily: In 2024, we operated the LRAUV as part of the HabCam Survey aboard the R/V Sharp and R/V Bigelow. In 2025, we built a second camera system and deployed two LRAUVs from a small boat during the HabCam Survey season to fill data gaps off of Long Island, New York. By 2026, we were using two LRAUVs to collect additional data independent of our HabCam Survey. The LRAUVs expand our survey coverage and validate our initial sea scallop abundance estimates.
“Our valuable partnership with WHOI made it possible to integrate LRAUV technology into the Atlantic sea scallop stock assessment,” explained Dr. Conor McManus, lead for the science center’s Marine Development and Advanced Technology Program. “The project team’s diverse expertise, co-development of the camera technology, and shared commitment to LRAUV mission operations and data acquisition have resulted in a successful collaboration."
Sampling in Challenging Sea Conditions
The LRAUV is built for energy efficiency and has a longer endurance than a typical AUV. The vehicle’s electrical system is able to turn off high-power sensors when they aren't actively collecting data to conserve battery life.
We typically program the vehicle to surface every 6 hours during a mission, but LRAUV technology allows us to delay surfacing if weather conditions aren’t amendable. When a LRAUV surfaces, it uses satellites to communicate with our scientists on shore. The LRAUV gives us its geographic coordinates and a status update.
“We have had a LRAUV out conducting a mission in 20–30 foot seas—conditions that a research vessel could not handle. The sea state is only an issue when the vehicle comes to the surface for communication or recovery,” explained Fairclough. “We schedule the recovery when we have a safe weather window to go out on a boat and recover the vehicle. If we need to delay because of bad weather, we can ‘park’ the LRAUV on the seafloor to sleep and conserve battery life until it’s safe to wake it up and recover it.”
What’s Next for This Small But Mighty Underwater Robot?
We expect to receive our own LRAUV, built by Saab, next year. This will allow us to continue improving sea scallop survey operations by:
- Enhancing sampling flexibility
- Expanding coverage
- Ensuring sampling continues in areas where we can no longer sample with traditional survey platforms
The LRAUV will also enhance sampling capabilities across our research areas. Future missions for the LRAUV in the Northeast may include:
- Studying plankton community dynamics
- Tracking whale foraging behavior with passive acoustics
- Using active acoustics to study fish populations
- Collecting water samples for environmental DNA analysis
We plan to test and develop these applications through continued partnership with WHOI. Other organizations have already used the LRAUVs to track harmful algal blooms and detect oil spills under Arctic ice, showing the remarkable potential of this small but mighty underwater robot.
“The modular nature of the LRAUV allows the platform to contribute to many of the Northeast Fisheries Science Center’s missions,” said Dr. McManus. “We look forward to building on the success of the optical scallop LRAUV work with our partners to address other stock and ecosystem research needs in the near future.”
