Sharks recruited as hurricane hunters off the US East Coast

Researchers at the University of Delaware have begun deploying sharks as living data buoys off the US East Coast, attaching sensors that beam ocean temperature, salinity and depth readings to satellites every time the animals surface. The project aims to fill a stubborn gap in hurricane forecasting: knowing exactly how much heat sits in the upper ocean layer that powers a storm's rapid intensification.

Principal investigator Aaron Carlisle, a professor in the School of Marine Science and Policy, said the team targets highly migratory species, shortfin mako, blue, smooth hammerhead and juvenile great white sharks, that frequent the North Atlantic in spring and summer. Unlike elephant seals, which have long carried similar instruments in polar waters, these sharks are abundant, wide-ranging and easier to handle without special permits.

Tagging trips start in early May, when the sharks move inshore from their winter grounds. Aboard a research vessel 50 to 65 kilometres offshore, the crew sets baited lines and typically waits two to three hours for a bite. The tagging itself is run "like a pit crew" and takes under five minutes: a CTD (conductivity, temperature, depth) package is bolted to the dorsal fin using corrodible hardware designed to fall off after months, and the animal receives a quick health check before release.

"We are really most interested in the heat content of the top layer of the ocean, which is known as the mixed layer. This is the part of the water column that really drives hurricane intensity, warmer mixed layer equals stronger hurricane."

Caroline Wiernicki, a doctoral candidate leading the fieldwork, contrasted the reality with pop-culture caricatures. "It's more like Bob from Accounting, clocking in with the day's temperature profiles before he heads back out," she said. The data stream could sharpen intensity forecasts for communities from North Carolina to Massachusetts, giving emergency managers a clearer picture of whether an approaching storm will weaken or explode before landfall.

Why sharks beat buoys

Fixed buoys and Argo floats provide valuable snapshots but cannot chase the warm eddies and currents that sharks naturally follow. By piggybacking on the animals' movements, the team hopes to capture the fine-scale ocean structure that models currently miss. If the pilot succeeds, the approach could be expanded to other basins and species, turning apex predators into a global ocean-observing fleet.

Next steps

The first tags are already transmitting. Over the coming months researchers will validate the shark-borne data against glider and satellite measurements, then feed it into operational hurricane models. Carlisle framed the payoff simply: "If we can show that sharks can help people, it's a win-win situation."