Sharks as Storm Sensors: Tagged Sharks Could Improve Hurricane Intensity Forecasts

Researchers at the University of Delaware are equipping sharks with small electronic CTD tags to collect near-real-time ocean data that can improve forecasts of hurricane intensity along the U.S. East Coast. The tags record electrical conductivity (a proxy for salinity), temperature and depth as sharks swim and surface, then transmit observations to satellites when the animal reaches the surface.

How the Program Works

The research team targets species and individuals that frequently surface so tags can send data to orbiting satellites. Earlier analyses identified promising North Atlantic candidates, including shortfin mako, blue sharks, smooth hammerheads and juvenile great white sharks. Fieldwork begins in early May, when highly migratory sharks move closer to shore, and teams operate roughly 30–40 miles (50–65 km) offshore.

Devices and Data

CTD tags measure conductivity (closely related to salinity), temperature and depth. The researchers focus on the ocean's mixed layer — the warm upper layer that fuels hurricanes. "We are really most interested in the heat content of the top layer of the ocean, which is known as the mixed layer," said Aaron Carlisle, principal investigator and professor in the School of Marine Science and Policy. "This is the part of the water column that really drives hurricane intensity — warmer mixed layer equals stronger hurricane — as it holds the heat that feeds hurricanes."

Tagging Process And Animal Care

Teams set baited lines from a research vessel and typically wait two to three hours for a shark to take the bait. Tags are attached to the dorsal fin and transmit each time the shark surfaces. Carlisle described the operation as run "like a pit crew" — the tagging usually takes under five minutes. The work follows institutional animal care protocols: tags are fastened with materials designed to corrode and drop off, and each shark receives a health check to avoid biasing behavior with stressed or injured animals.

Caroline Wiernicki, a doctoral candidate, offered a lighthearted contrast to dramatic media portrayals: "It's more like Bob from Accounting, clocking in with the day's temperature profiles before he heads back out."

Why This Matters

If successful, shark-borne observations can fill gaps in ocean sampling where ships and buoys are sparse, improving model input for oceanographic, atmospheric and climate forecasts. More accurate information about mixed-layer heat content could help forecasters better predict hurricane intensification, giving coastal communities from North Carolina to Massachusetts more reliable data to prepare for approaching storms.

"Most people will never encounter a shark in the wild," Carlisle added, "but in reality they are amazing animals perfectly adapted to the ocean, and we can learn a huge amount from them. If we can show that sharks can help people, it's a win-win situation."

Reporting by Marta Serafinko in Gdansk; Editing by Will Dunham.