How can underwater gliders transform the way we study the ocean?
NOAA Fisheries scientists are eager to explore this question during a unique glider challenge in Hawaiʻi this month.
They are leading a rigorous assessment of gliders equipped with passive acoustic sensors to record underwater sounds.
The gliders, and their pilots, will complete a series of missions to demonstrate their capabilities in studying marine mammals and their ecosystems.
Industry and academic partners joining the 2-week challenge include:
- Cornell University
- Oregon State University
- ALSEAMAR
- Hefring Engineering
- JASCO Applied Sciences
- Teledyne Marine
“It’s a really important event for us,” said Erin Oleson, Pacific Islands Fisheries Science Center Protected Species Division director. “By advancing the use of innovative and cost-effective uncrewed vessels, like gliders, we can more precisely support marine species and ecosystems, which in turn supports a strong and sustainable ocean economy.”
How We Study Marine Mammals
For decades, we have conducted ship-based surveys for large-scale monitoring of whales, dolphins, and porpoises. The data allows us to estimate population size, location, and trends to support conservation and sustainable fisheries.
These ship-based surveys are considered the “gold standard” for monitoring marine mammals. They provide critical data through visual observations, acoustic recordings, tissue sampling, and satellite tagging.
However, ship-based surveys have limitations. They require extensive planning and can be costly and resource intensive, so they typically occur every few years. That means teams may not get a precise count of whales and dolphins that move through the region outside of the survey periods, leaving critical gaps in understanding.
The Glider Opportunity
Passive acoustic-equipped gliders offer a powerful complement to shipboard surveys—filling data gaps and expanding coverage opportunities.
“We know that passive acoustic monitoring is a really exceptional, proven method for detecting marine mammals underwater,” Oleson said. “Gliders give us a way to move passive acoustic monitoring technology around the ocean in a way that replicates and enhances our ship surveys. It’s exciting.”
In contrast to the ship-based surveys, gliders offer rapidly advancing capabilities and a cost-effective way to survey more frequently and across more areas. This additional glider data would help ensure federal protections are right-sized for marine mammals and sustainable fisheries.
Gliders also offer the potential to support real-time responses in the future—like locating a dolphin pod scientists need to tag, or alerting fishermen to whales near a fishing spot.
Engineering Trade-Offs: Finding the Right Tool
No single glider is the best at everything. One underwater glider system might excel at gathering data across a large area, while another may be quieter and better able to listen for whales and dolphins.
“We need to know what the gliders can do well, and where they might be limited.” Shannon Rankin, passive acoustic ecologist with the Southwest Fisheries Science Center. “These insights will help us determine the best way to collect data for various management needs.”
During the challenge, each pilot and glider will complete four types of mission:
- Maximum Survey Coverage: Assessing how much area the glider can cover
- Low Noise: Prioritizing the clearest possible acoustic recordings
- Balanced: Striking a middle ground between maximum coverage and low noise
- Drifting: Floating without pumps or motors to capture the most quiet performance
The team of scientists will evaluate how each glider system performed using several key criteria:
- Piloting: How user-friendly is each model, and how easily can pilots adjust a mission once the glider is underway?
- Navigation: Which designs stay on course most effectively given changing conditions, such as ocean currents and underwater hazards?
- Endurance: Which setups offer the longest battery life and data storage, or memory, during various mission modes?
- Noise: Does the glider’s “self-noise”—such as mechanical sounds, electronic interference, and water flow over the glider—interfere with the ability to identify and record ocean sounds?
National Impacts on the Future of Ocean Monitoring
This Hawaiʻi glider challenge, while based in the Pacific, is part of a larger effort with broader implications.
The findings will help NOAA, academia, and industry accelerate glider development and use in marine mammal and ecosystems research nationwide.
“Our goal is to transition to using passive acoustic gliders to augment our shipboard surveys to better support our management needs,” Rankin said. By identifying the strengths of each underwater glider system, scientists aim to operationalize technologies that are best suited for monitoring whales, dolphins, and the ecosystems on which they—and we—depend.
This is just the start of how these tools can be used, Oleson added.
These gliders, with a variety of data collection packages, could be used beyond marine mammal monitoring. They could help us track fish spawning and distribution, predict red tides or algal blooms, measure marine food web changes, and more. They will be foundational tools for the future of NOAA Fisheries surveys.
Next Mission: Comparing Glider and Ship-Based Surveys in Hawaiʻi
After this challenge ends, some of the gliders will begin another research mission around the main Hawaiian Islands. They will survey the same area as our winter Hawaiian Islands Cetacean and Ecosystem Assessment Survey.
Learn more about whale and dolphin surveys in the Pacific
The concurrent surveys will provide scientists an opportunity to directly compare the results from traditional survey methods with the results from the gliders. This is a key step in implementing uncrewed systems.
Follow Along
Meet the glider pilot professionals for this underwater challenge in our newest “Sound Bytes” blog. Follow the blog—and our social media—for an insider look at the future of our marine mammal research.
