Somewhere off the Northwest Atlantic, a blue shark (Prionace glauca) glides through shifting layers of water, diving hundreds of feet below the surface before rising again. It is hunting, navigating, living its (best) life. And yet, every movement it makes allows for a piece of technology on its fin to record temperature, depth and location. A trail of data that, until recently, was used mostly to understand the shark itself. Now, however, that same data is helping scientists better predict the future of our planet.
I previously reported on Dr. Camille M. L. S. Pagniello’s study where salmon sharks (Lamna ditropis) were being fitted with a new custom-built tag, called a CTD-SRDL, “allowing researchers to track temperature and salinity profiles while following the shark’s natural movements.” The data collected from the tagged shark was then compared with measurements from Argo floats in the same region and while both datasets offered valuable insights, the shark’s data revealed much finer detail in certain areas, particularly in dynamic zones shaped by eddies and coastal interactions. Marine predators like sharks are actively seeking out dynamic ocean features such as fronts and eddies, areas where different water masses collide and mix. These regions are biologically rich and physically complex, and are where traditional observing systems struggle to keep up. While satellites can tell us a lot about the ocean surface, they cannot see very far below it. And while buoys and research vessels provide detailed data, they, too, are limited in coverage and expensive to maintain. The ocean is vast, and much of it remains under-sampled. Sharks, on the other hand, are already there.
This new study published in npj Climate and Atmospheric Science led by Woods Hole Oceanographic Institution scientist Dr. Laura H. McDonnell builds on Pagniello’s idea. In her study, the team tagged 18 blue sharks and one shortfin mako shark (Isurus oxyrinchus), equipping them with satellite-linked devices capable of recording temperature and depth alongside location data. As these animals moved through the ocean, they transmitted more than 8,200 temperature-depth profiles, reaching depths of nearly 6,562 feet (2,000 meters). The research team then took a subset of this data and fed it into a seasonal climate model, one that is part of a broader forecasting system used by scientists to predict ocean and atmospheric conditions. They compared forecasts generated with and without the shark-derived data and were able to significantly improve the accuracy of ocean forecasts thanks to the sharks, particularly in coastal and shelf regions where conditions can change rapidly and where accurate predictions are especially important for ecosystems and human activities. In fact, by integrating the data collected by these mobile ocean sensors into climate models, some forecast errors at the ocean surface dropped by as much as 40 percent!
So while scientists shouldn’t worry about sharks outright taking their oceanographer jobs, they may have them as “colleagues” in a sort of sense. Because if 19 sharks can make a measurable difference, what could hundreds or thousands do? What about other marine animals that travel different routes or occupy different depths? There is already a growing field of research exploring animal-borne sensors, from seals measuring polar conditions to turtles tracking coastal environments. Sharks now add another layer to that picture, particularly in regions where they naturally aggregate around ocean features that matter most for climate dynamics. “Tagged sharks won’t replace conventional observing systems,” said McDonnell in a press release. “What the preliminary results do show is that tagged marine predators can provide complementary in-situ observations at the surface and at depth.” But even as a complementary tool, the potential is compelling. Better ocean forecasts can improve fisheries management, helping to ensure that seafood supply chains remain stable and sustainable. They can support marine operations by providing more accurate information about conditions at sea. They can also deepen our understanding of how climate variability affects coastal communities, many of which are already facing increasing uncertainty.
Sharks are frequently portrayed as threats, reduced to headlines and the “bloodthirsty killer” stereotype. Yet here they are, contributing to one of the most complex scientific challenges of our time. It makes you wonder how many other overlooked connections are out there, waiting to be recognized. If a shark can help improve a forecast, what else might be possible when we start looking at the natural world not just as something to study, but as something to learn from in entirely new ways?
