A recent issue of the scientific journal Communication Earth & Environment notes that nautical charts across many regions only provide rough depth estimates and often miss entire seamounts or submarine canyons. To tackle this gap, researchers turned to a surprising ally: seals.
In a collaborative effort, teams attached GPS tracking devices to elephant seals and Weddell seals. For years, scientists have relied on these marine mammals around Antarctica to gather essential data on ocean temperature and salinity, turning the seals into living data collectors as they move through the Southern Ocean.
For the current study, researchers compared the seals’ location and depth readings with the available, less detailed seafloor maps. The comparison revealed instances where the seals’ dives penetrated depths deeper than those suggested by existing charts, indicating that many depth estimates remain inaccurate and that parts of the seafloor have yet to be properly charted.
In Vincennes Bay, eastern Antarctica, the seals helped identify a substantial hidden submarine canyon plunging more than 1.5 kilometers below the surface. A research ship from Australia, RSV Nuyina, subsequently mapped the canyon with sonar, and the researchers proposed naming the feature Mirunga-Nuyina Canyon to honor both the Mirounga elephant seals involved in the expedition and the vessel that confirmed the discovery.
Clive McMahon, an Integrated Marine Observing System researcher in Australia and a co‑author of the study published in Communications Earth & Environment, commented that the seals pointed the way while the ship provided the precise measurements that cemented the finding.
While seals offer valuable data, they cannot completely chart the ocean floor. The trackers used in the study could determine a seal’s geographic position within about 3 kilometers, which supplies useful context but falls short of high-precision bathymetry. Moreover, since seals do not always dive to the actual seafloor, their data indicate only where the bottom is deeper than current maps, not the maximum depth at every location.
McMahon notes that this data quality could improve with more accurate GPS devices and by analyzing the seals’ diving patterns to distinguish dives that reach the seafloor from those that stay within the water column before resurfacing. In other words, better sensors paired with smarter interpretation of dive behavior could yield more reliable bathymetric insights from these marine mammals.
As a result, the approach of using seals for depth assessment could be refined and expanded, contributing to a more complete picture of the seafloor. The study underscores the potential of integrating animal-borne sensors with traditional mapping methods to fill gaps in global bathymetry and to inform safe navigation, climate research, and marine biology alike.
In the broader context, the method aligns with growing efforts to crowd in novel data sources for ocean science. Advances in miniaturized, robust tracking technology, plus sophisticated data fusion techniques, are enabling researchers to extract meaningful, location-specific depth information from living partners of the sea. The ongoing work aims to reduce map gaps, improve the accuracy of depth estimates, and support more accurate models of ocean circulation and ecosystem dynamics.
Ultimately, researchers anticipate that continued collaboration between wildlife telemetry and high-resolution sonar surveys will yield richer, more reliable bathymetric maps, helping to illuminate the hidden topography of the world’s oceans and support the stewardship of marine environments by Canada, the United States, and global partners alike.